Academic literature on the topic 'Force based design (FBD)'
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Journal articles on the topic "Force based design (FBD)"
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Puspita, Annisaa Dina, and Anis Rosyidah. "Force Based Design and Direct Displacement Based Design for Dual System Structure." Logic : Jurnal Rancang Bangun dan Teknologi 19, no. 3 (2019): 162. http://dx.doi.org/10.31940/logic.v19i3.1454.
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The Force Based Design (FBD) and the Direct Displacement-Based Design (DDBD) are methods for designing seismic-resistant buildings. Building structures designed, are expected to be suitable with the purpose and usefulness of a building. For this reason, this study compares the performance of dual system structures using the DDBD and FBD methods that aim to prove better performance with consideration of safety against users during an earthquake. This research method uses design analysis method to compare the value of the base shear force, reinforcement ratio, and performance level using software for static nonlinear pushover analysis. The results showed the value of the base shear force x direction of the DDBD method was 17.57% smaller than the FBD method, whereas for the y direction the DDBD value was greater than 9.38% of the FBD. The value of the reinforcement ratio of the beam, column and shear wall results is greater DDBD than FBD. The actual drift of the DDBD and FBD methods is slightly different. So that both are at the same level of performance, namely damage control. The performance level has not reached the performance target of life safety design in DDBD, but the structure has met the level performance requirements for offices.
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Zhang, Qi, M. Shahria Alam, Saqib Khan, and Jianping Jiang. "Seismic performance comparison between force-based and performance-based design as per Canadian Highway Bridge Design Code (CHBDC) 2014." Canadian Journal of Civil Engineering 43, no. 8 (2016): 741–48. http://dx.doi.org/10.1139/cjce-2015-0419.
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Performance-based design (PBD) was first introduced in Canadian Highway Bridge Design Code (CHBDC) in 2014. Performance-based design is the design that meets multiple performance criteria under different earthquake hazards. To investigate the impact of changes in CHBDC 2014, a four-span concrete highway bridge is designed and evaluated using force-based design (FBD) and PBD methods as per CHBDC 2014, and FBD method as per CHBDC 2006. By incorporating soil–structure interaction (using p–y curves) nonlinear pushover and dynamic time history analyses are conducted to assess the seismic performance of these bridges. Maximum strains of concrete and reinforcing steel are compared among the three designs to determine their performance levels. It is concluded that PBD (CHBDC 2014) is highly conservative compared to FBD (for both CHBDC 2014 and 2006). For the three-level PBD approach, the design is governed by the criterion of reinforcing steel not yielding under the design earthquake (with 475 years return period).
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MEENA, A. BHAGAT, and KAKDE SHUBHANGI. "STUDY ON PERFORMANCE ON FORCE BASED DESIGN VS DISPLACEMENT BASED DESIGN IN EVALUATING SEISMIC DEMAND ON REGULAR RCC STRUCTURE." JournalNX - a Multidisciplinary Peer Reviewed Journal 3, no. 6 (2017): 65–68. https://doi.org/10.5281/zenodo.1421037.
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Recently many research projects related to the design of earthquake resistant structures and various robust construction methods are expected to be earthquakes and the study explains two major methods of Force Based Design (FBD) and Direct Displacement Based Design(DDBD) in which the first is a Conventional method, while later one is an approach to design performance. Design and analysis were in bare-frame dimensions of four, eight and twelve stories based on the following IS 456, IS 1893 codes: 2000, ETABSA and two design approaches should be studied.
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Fox, Matthew J., Timothy J. Sullivan, and Katrin Beyer. "Comparison of Force-Based and Displacement-Based Design approaches for RC coupled walls in New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 47, no. 3 (2014): 190–205. http://dx.doi.org/10.5459/bnzsee.47.3.190-205.
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Reinforced concrete coupled walls are a common lateral load resisting system used in multi-storey buildings. The effect of the coupling beams can improve seismic performance, but at the same time adds complexity to the design procedure. A case study coupled wall building is designed using Force-Based Design (FBD) and Direct Displacement-Based Design (DDBD) and in the case of the latter a step by step design example is provided. Distributed plasticity fibre-section beam element numerical models of the coupled walls are developed in which coupling beams are represented by diagonal truss elements and experimental results are used to confirm that this approach can provide a good representation of hysteretic behaviour. The accuracy of the two different design methods is then assessed by comparing the design predictions to the results of non-linear time-history analyses. It is shown that the DDBD approach gives an accurate prediction of inter-storey drift response. The FBD approach, in accordance with NZS1170.5 and NZS3101, is shown to include an impractical procedure for the assignment of coupling beam strengths and code equations for the calculation of coupling beam characteristics appear to include errors. Finally, the work highlights differences between the P-delta considerations that are made in FBD and DDBD, and shows that the code results are very sensitive to the way in which P-delta effects are accounted for.
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Reza, Samy M., M. Shahria Alam, and Solomon Tesfamariam. "Seismic performance comparison between direct displacement-based and force-based design of a multi-span continuous reinforced concrete bridge with irregular column heights." Canadian Journal of Civil Engineering 41, no. 5 (2014): 440–49. http://dx.doi.org/10.1139/cjce-2012-0278.
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North American bridge design codes, e.g., Canadian Highway Bridge Design Code and AASHTO 2007, follow force-based design (FBD) method, which is focused at the target force resistance capacity of the structure. Displacement-based design (DBD) method, on the other hand, aims to ensure a target maximum displacement of the bridge during earthquakes in a specific zone. In this study, bridges with irregular column heights have been designed according to DBD and FBD (as per Canadian standards and AASHTO 2007) considering seismic loading. Subsequently, seismic performances of the bridges designed with the two different methods have been compared by conducting nonlinear dynamic analyses in the longitudinal direction. Maximum and residual displacements and energy dissipation capacity are used as performance indicators. This study outlines the necessity of possible modification in the current Canadian seismic design standards as well as DBD for bridges with irregular column heights.
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Parisi, Fulvio. "Seismic Design of Box-Type Unreinforced Masonry Buildings Through Direct Displacement-Based Approach." Open Construction and Building Technology Journal 10, no. 1 (2016): 293–311. http://dx.doi.org/10.2174/1874836801610010293.
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In the last decade, displacement-based seismic design procedures have been recognised to be effective alternatives to force-based design (FBD) methods. Indeed, displacement based design (DBD) may allow the structural engineer to get more realistic predictions of local and global deformations of the structure, and hence damage, under design earthquakes. This facilitates the achievement of performance objectives and loss mitigation in the lifetime of the structure. Nonetheless, DBD needs further investigation for some structural types such as masonry buildings. In this paper, a direct displacement based design (DDBD) procedure for unreinforced masonry (URM) buildings is presented and critically compared to FBD. The procedure is proposed for box-type URM buildings with reinforced concrete slabs, bond beams and lintels above openings, which have shown acceptable seismic performance in severe earthquakes preventing out-of-plane failure modes. Seismic design of a three storey brick masonry building in a high seismicity region is discussed as a case study. The effects of ordinary and near-field design earthquakes, as well as load combinations and accidental eccentricity prescribed by current codes, were investigated. Finally, design solutions provided by FBD and DDBD were optimised and their construction costs were estimated. It was found that, particularly at small epicentral distances, neglecting the combination of horizontal seismic actions and accidental eccentricity may induce significant underestimation and an ideally more uniform distribution of strength demands on URM walls. In addition, construction costs resulting from DDBD may be significantly lower than those related to code based FBD procedures.
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Pudjisuryadi, Pamuda, William Sumargo, Alvin Kho, and Benjamin Lumantarna. "Performance Evaluation of Simple Regular Buildings using FBD and DDBD Methods with a Consistent Target Drift." Civil Engineering Dimension 27, no. 1 (2025): 59–72. https://doi.org/10.9744/ced.27.1.59-72.
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The Direct Displacement Based Design (DDBD) method, proposed by Priestley, is an alternative to the traditional Force-Based Design (FBD) method for earthquake-resistant design. This study compares the performance of 4-story and 12-story buildings designed using both FBD and DDBD with the same target drift of 2%. The differences in base shear used for the design of the two approaches are discussed. To evaluate the buildings' performance, Nonlinear Dynamic Procedure (NDP) analysis, or nonlinear time history analysis, was conducted considering 500 and 2500 years return period earthquakes. The results indicate that the actual drift of both designs deviates from the target drift; however, the observed drifts remain within the maximum limits set by FEMA 356. Moreover, plastic damages were observed in unexpected areas of the columns, suggesting that the strong-column weak-beam design concept, as stipulated by building codes, does not entirely prevent damage to columns.
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Palsanawala, T. N., K. M. Gondaliya, and S. A. Vasanwala. "Seismic fragility comparison of FBD and DDBD designed RC frame using incremental dynamic analysis." IOP Conference Series: Earth and Environmental Science 1326, no. 1 (2024): 012006. http://dx.doi.org/10.1088/1755-1315/1326/1/012006.
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Abstract Direct displacement-based design (DDBD) is a design approach in which structures are designed for predefined displacements to withstand earthquakes within specified performance criteria. In order to defeat the drawbacks of force-based design (FBD), which is based on stiffness assumptions, the DDBD method evaluated the displacement constraint in which structure response must remain within the predetermined displacement. The fragility assessment reveals the structure’s probability of future collapse from the nonlinear analysis will help to detect the structure’s performance. In this study, Incremental dynamic analysis (IDA) is performed on a four-story reinforced concrete (RC) frame structure designed using DDBD and FBD approach to predict nonlinear structural behavior in earthquake-prone regions. The RC frame is designed to satisfy the immediate occupancy (IO) performance limit of 1% drift while taking into account the DDBD method. Sixteen ground motions with two horizontal directions mounted to various intensity levels represented by peak ground acceleration (PGA) are used to perform IDA. Fragility curves are generated from logarithms of intensity measures (IM) computed from the IDA. As a result, earthquake damage in terms of the probability of collapse and inter-storey drift ratio are compared for both approaches and using the DDBD approach, four times less PGA occurrence is observed for the IO performance limit compared to FBD.
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Falcão Moreira, Rodrigo, Humberto Varum, and José Miguel Castro. "On the Applicability of Conventional Seismic Design Methodologies to Hybrid RC-Steel Systems." Buildings 12, no. 10 (2022): 1558. http://dx.doi.org/10.3390/buildings12101558.
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This paper addresses the application of conventional (force-based) seismic design methodologies to hybrid RC-steel systems. The q-factor-based EC8-3 seismic assessment procedure is first reviewed. A case-study application follows, analyzing and discussing the difficulties a practitioner will face when assessing the efficiency of a steel-brace retrofitting system designed within the framework of EC8-1. Afterward, the performance of the obtained retrofitted structure is evaluated using nonlinear analysis. The obtained results are discussed in light of the EC8-3 performance requirements, and conclusions are drawn about the adequacy of the force-based design (FBD) methodology (and associated q-factors) for such situations. The study shows that the process does not ensure the adequate seismic behavior of the retrofitted structures. It thus calls for the development of an effective performance-based design methodology that explicitly considers the interaction between the two structural systems (RC structure and steel braces), namely the influence of the steel braces’ resistance on the deformation capacity of RC members.
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Hilmi, Zihan Ramdan, Bayzoni Bayzoni, and Hasti Riakara Husni. "Evaluation of Stucture Performance the Building a Regional Police Headquarters of Lampung using Direct Displacement Based Design Method of Base Shear Forces." Jurnal Rekayasa Sipil dan Desain 8, no. 4 (2021): 667–80. https://doi.org/10.23960/jrsdd.v8i4.1519.
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Direct Displacement Based Design (DDBD) is a new method in computing the loading of earthquakes resistant building structures with displacement as a performance target, which is considered to be more efficient than the method often used previously, namely the Force Based Design (FBD). The purpose of this research is evaluate the performance of the Lampung Regional Police Headquarters building based on the ATC-40 and FEMA 440, where the dimensions of the structure used from shop drawings and can be change if the dimensions not meet requirements. The loads used are gravity loads and base shear force designed using DDBD, where the design performance target is life safety. In the evaluation process of this research, there is one type of main beam that must be changes in dimensions, and the result of structure performance evaluation is immediate occupancy, based on ATC-40 and FEMA 440. Keywords: Displacement, DDBD, Evaluation of Performance.
Dissertations / Theses on the topic "Force based design (FBD)"
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Gunzel, Charles A. "FSR based force torque transducer design." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA271337.
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Manafpour, Alireza. "Force and displacement-based seismic design of RC buildings." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398834.
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ZERBIN, Matteo. "Force-Based Seismic Design of Dual System RC Structures." Doctoral thesis, Università degli studi di Ferrara, 2017. http://hdl.handle.net/11392/2488041.
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Seismic design of standard structures is typically based on a force-based design approach. Over the years, this approach has proven to be robust and easy to apply by design engineers and – in combination with capacity design principles – it provided a good protection against premature structural failures. However, it is also known that the force-based design approach as it is implemented in the current generation of seismic design codes suffers from some shortcomings. One of these relates to the fact that the base shear is computed using a pre-defined force reduction factor, which is constant for a certain type of structural system. As a result of this, for the same design input, structures of the same type but different geometry are subjected to different ductility demands and show therefore a different performance during an earthquake. The objective of this research is to present an approach for computing force reduction factors using simple analytical models. These analytical models describe the deformed shape at yield and ultimate displacement of the structure and only require input data that are available when starting the design process, such as geometry and general material properties. The displacement profiles are obtained from section dimensions and section ductility capacities that can be estimated at the beginning of the design process. The so computed displacement ductility is taken as proxy of the force reduction factor. Such analytical models allow to link global to local ductility demands and therefore to compute an estimate of the force ductility reduction factors for wall and frame structures. Finally, this research develops an approach for frame-wall structures as combination of results obtained for wall and frame systems. The proposed method is applied to a set of frame-wall structures and validated by means of nonlinear time history analyses. Obtained results show that the proposed method yields a more accurate seismic performance than the current code design approach. The presented work therefore contributes to the development of revised force-based design guidelines for the next generation of seismic design codes.<br>La progettazione sismica di strutture è tipicamente basato su un approccio progettuale basato sulle forze. Nel corso degli anni, questo approccio ha dimostrato di essere robusto e facile da applicare dai progettisti e, in combinazione con il principio di gerarchia delle resistenze, fornisce una buona protezione contro i meccanismi di collasso fragili. Tuttavia, è anche noto che l'approccio di progettazione in forze così come attuato nell’odierna generazione di normative soffre di alcune carenze. Uno di questi riguarda il fatto che il tagliante alla base è calcolato utilizzando un fattore di struttura predefinito, cioè costante per tipo di sistema strutturale. Di conseguenza, per lo stesso input di progettazione, strutture dello stesso tipo ma diversa geometria sono sottoposti ad una diversa domanda di duttilità e mostrano quindi una diversa prestazione durante un evento sismico. L'obiettivo di questo studio è quello di presentare un approccio per il calcolo fattori di struttura utilizzando modelli analitici semplici. Questi modelli analitici descrivono la deformata a snervamento e spostamento ultimo della struttura e richiedono solo dati di input disponibili all’inizio del processo di progettazione, quali dati geometrici e proprietà dei materiali. La deformata della struttura ottenuta dalle dimensioni delle sezioni e la capacità in termini di duttilità sezionale possono essere stimati all'inizio della progettazione. La duttilità è alla base della formulazione del fattore di struttura come proposto dai modelli analitici presentati. Tali modelli analitici permettono di collegare le duttilità sezionali alla duttilità strutturale e quindi calcolare una stima del fattore di struttura per struttura a pareti e a telaio. Infine, si sviluppa un approccio per strutture duali di tipo telaio-parete come combinazione di risultati ottenuti per i sistemi singoli. Il metodo proposto è applicato ad un insieme di strutture duali e validato con analisi dinamiche non lineari. Si dimostra che il metodo proposto produce una più accurata prestazione sismica rispetto all'approccio progettuale delle normative odierne. Il lavoro presentato contribuisce pertanto allo sviluppo di nuove linee guida per la progettazione sismica nella prossima generazione di normative.
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West, Jerry. "Orthoplanar Spring Based Compliant Force/Torque Sensor for Robot Force Control." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6637.
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A compliant force/torque sensor for robot force control has been developed. This thesis presents methods of designing, testing, and implementing the sensor on a robotic system. The sensor uses an orthoplanar spring equipped with Hall-effect sensors to measure one component of force and two moment components. Its unique design allows for simple and cost effective manufacturing, high reliability, and compactness. The device may be used in applications where a robot must control contact forces with its environment, such as in surface cleaning tasks, manipulating doors, and removing threaded fasteners. The compliant design of the sensor improves force control performance and reduces impact forces.
Sensor design considerations are discussed, followed by a discussion of the proposed design concept. Theoretical compliance and stress analysis of the orthoplanar spring is presented that allows for rapid design calculations; these calculations are validated via finite element analysis. A mechanical design method is given which uses the results of the compliance and stress analysis. Transducer design is then addressed by developing a model of the sensor. The design methods are used to design a prototype sensor which is tested to determine its instrument uncertainty. Finally, the sensor is implemented on a robotic platform to test its performance in force control.
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Li, Min 1977 Apr 2. "Continuum design sensitivity analysis based force calculation in EM devices." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111523.
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The continuum design sensitivity analysis (CDSA) has been applied to the magnetostatic and electrostatic force calculation. This method allows the computation of the net loading force on a body as well as the force distribution on the surface of the body. An algorithm for force calculation combined with a standard field analysis software package is presented. The efficiency and accuracy of the method is proved through the numerical implementation applied to a set of test examples. In addition, the new approach has several advantages over the traditional methods based on the Maxwell Stress Tensor, such as no air gap or artificial interference with the original model is required. Particularly, the performance analysis of a MEMS micro-mirror using CDSA torque calculation is conducted for the first time.
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Otero, Richard Edward. "Problem decomposition by mutual information and force-based clustering." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43641.
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The scale of engineering problems has sharply increased over the last twenty years. Larger coupled systems, increasing complexity, and limited resources create a need for methods that automatically decompose problems into manageable sub-problems by discovering and leveraging problem structure. The ability to learn the coupling (inter-dependence) structure and reorganize the original problem could lead to large reductions in the time to analyze complex problems. Such decomposition methods could also provide engineering insight on the fundamental physics driving problem solution.
This work forwards the current state of the art in engineering decomposition through the application of techniques originally developed within computer science and information theory. The work describes the current state of automatic problem decomposition in engineering and utilizes several promising ideas to advance the state of the practice.
Mutual information is a novel metric for data dependence and works on both continuous and discrete data. Mutual information can measure both the linear and non-linear dependence between variables without the limitations of linear dependence measured through covariance. Mutual information is also able to handle data that does not have derivative information, unlike other metrics that require it. The value of mutual information to engineering design work is demonstrated on a planetary entry problem. This study utilizes a novel tool developed in this work for planetary entry system synthesis.
A graphical method, force-based clustering, is used to discover related sub-graph structure as a function of problem structure and links ranked by their mutual information. This method does not require the stochastic use of neural networks and could be used with any link ranking method currently utilized in the field. Application of this method is demonstrated on a large, coupled low-thrust trajectory problem.
Mutual information also serves as the basis for an alternative global optimizer, called MIMIC, which is unrelated to Genetic Algorithms. Advancement to the current practice demonstrates the use of MIMIC as a global method that explicitly models problem structure with mutual information, providing an alternate method for globally searching multi-modal domains. By leveraging discovered problem inter-dependencies, MIMIC may be appropriate for highly coupled problems or those with large function evaluation cost. This work introduces a useful addition to the MIMIC algorithm that enables its use on continuous input variables. By leveraging automatic decision tree generation methods from Machine Learning and a set of randomly generated test problems, decision trees for which method to apply are also created, quantifying decomposition performance over a large region of the design space.
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Meaders, John Christian. "An Optimization-Based Framework for Designing Robust Cam-Based Constant-Force Compliant Mechanisms." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1423.
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Constant-force mechanisms are mechanical devices that provide a near-constant output force over a prescribed deflection range. This thesis develops various optimization-based methods for designing robust constant-force mechanisms. The configuration of the mechanisms that are the focus of this research comprises a cam and a compliant spring fixed at one end while making contact with the cam at the other end. This configuration has proven to be an innovative solution in several applications because of its simplicity in manufacturing and operation. In this work, several methods are introduced to design these mechanisms, and reduce the sensitivity of these mechanisms to manufacturing uncertainties and frictional effects. The mechanism's sensitivity to these factors is critical in small scale applications where manufacturing variations can be large relative to overall dimensions, and frictional forces can be large relative to the output force. The methods in this work are demonstrated on a small scale electrical contact on the order of millimeters in size. The method identifies a design whose output force is 98.20% constant over its operational deflection range. When this design is analyzed using a Monte Carlo simulation the standard deviation in constant force performance is 0.76%. When compared to a benchmark design from earlier research, this represents a 34% increase in constant-force performance, and a reduction from 1.68% in the standard deviation of performance. When this new optimal design is evaluated to reduce frictional effects a design is identifed that shows a 36% reduction in frictional energy loss while giving up, however, 18.63% in constant force.
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Flemmer, Henrik. "Control Design and Performance Analysis of force Reflective Teleoperators - A Passivity Based Approach." Doctoral thesis, KTH, Machine Design, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3795.
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<p>In this thesis, the problem of controlling a surgical masterand slave system with force reflection is studied. The problemof stiff contacts between the slave and the environment isgiven specific attention. The work has been carried out at KTHbased on an initial cooperation with Karolinska Sjukhuset. Theaim of the over all project is to study the possibilities forintroduction of a force reflective teleoperator in neurologicalskullbase operations for the particular task of bone millingand thereby, hopefully, increase patient safety, decreasesurgeon workload and cost forthe society.</p><p>The main contributions of this thesis are:</p><p>Derivation of a dynamical model of the master andoperators finger system and, experimental identificationof ranges on model parameter values. Based on this model, theinteraction channel controllers optimized for transparency arederived and modified to avoid the influence of the uncertainmodel parameters. This results in a three channel structure. Todecrease the influence of the uncertain parameters locally atthe master, a control loop is designed such that the frequencyresponse of the reflected force is relatively unaffected by theuncertainties, a result also confirmed in a transparencyanalysis based on the H-matrix. The developed teleoperatorcontrol structure is tested in experiments where the operatorcould alter the contact force without facing any problems aslong as the slave is in contact with the environment.</p><p>As a result of the severe difficulties for the teleoperatorto move from free space motion to in-contact manipulationwithout oscillative behaviour, a new detection algorithm basedon passivity theory is developed. The algorithm is able todetect the non-passive behaviour of the actual teleoperatorinduced by the discrete change in system dynamics occurring atthe contact instant. A stabilization controller to be activatedby the detection algorithm is designed and implemented on themaster side of the teleoperator. The detection algorithm andthe stabilization controller are shown highly effective in realexperiments.</p><p>All major research results presented in the thesis have beenverified experimentally.</p><p><b>Keywords</b>Teleoperator, Force Feedback, Passivity, StiffContacts, Control, Robustness, Transparency, Bone Milling,Uncertainty</p>
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Dragana, Vasiljević. "Design, fabrication and characterisation of humidity and force sensors based on carbon nanomaterials." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107609&source=NDLTD&language=en.
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Detection and control of humidity is very important in our everyday life.Humidity sensors are used in many areas, such as meteorology,environmental protection, medicine, food industry, agriculture, etc.Various transduction techniques, such as capacitive, resistive, acoustic,optical and mechanical, have been adopted for the design of humiditysensors.In the last two decades, carbon nanomaterials materials,especially graphene, are taking their place in the production of humiditysensors. In addition to graphene, graphene oxide (Graphene-oxide-GO)is involved in many areas from electronics to sensors. Printed electronicsincreasingly becomes the leading technology in the fabrication ofsensors. In addition to inexpensive manufacturing and additive processeswith reduced infrastructure, the benefits of printed technology are lowpowercomponents, flexible, transparent, thin, components that can beembedded in/on clothes, as well as the production of a large number ofcomponents. In the last few years, robots are more involved in human’slife, which has led to the need for advanced research in the field ofrobotics. People communicate with the environment using four senses:touch, hearing, sight and taste. The sense of touch allows people to grabvarious objects, lift them, perform various tasks, etc. For this reason, it isvery important to develop touch sensors, that is, the sensors that will beincorporated into robotic fingers. As one type of such sensor, ForceSensing Resistors (FSR) are used. In these sensors, there is a change inresistance if the sensor is affected by a certain force.<br>Детекција и контрола влажности су од суштинског значаја у нашемсвакодневном животу. Сензори влаге се користе у многим областима,као што су метеорологија, заштита животне средине, медицина,прехрамбена индустрија, пољопривреда, итд. За дизајн сензора влагеуглавном се користе капацитивне, резистивне, акустичне, механичкеили оптичке структуре. У посљедње двије деценије све више се користенаноструктурни угљенични материјали, посебно графен. Поред графенавелику пажњу у многим областима од електронике до сензора јепривукао графен-оксид (Graphene-oxide - GO). Штампана електроникасве више постаје водећа технологија у изради сензора. Поред јефтинеизраде и адитивних процеса са смањеном инфраструктуром, предностиштампане технологије су компоненте мале масе, савитљиве,транспарентне, танке, компоненте које се могу уградити у/на гардеробуи носити, као и производња великог броја компоненти. У последњихнеколико година роботи се све више укључују у људски живот, што једовело до потребе за усавршавањем у области роботике. Људи саокружењем комуницирају помоћу четири чула: додира, слуха, вида иукуса. Чуло додира људима омогућава да дохвате различите предмете,подигну их, обављају различите задатке, итд. Из тог разлога је развојсензора додира, односно сензора који би се уградили у роботске прсте,од веома великог значаја. Као једна врста таквих сензора су отпорничкисензори силе (Force Sensing Resistors - FSR). Код ових сензора долазидо промјене отпорности уколико се на сенсор дјелује одређеном силом.<br>Detekcija i kontrola vlažnosti su od suštinskog značaja u našemsvakodnevnom životu. Senzori vlage se koriste u mnogim oblastima,kao što su meteorologija, zaštita životne sredine, medicina,prehrambena industrija, poljoprivreda, itd. Za dizajn senzora vlageuglavnom se koriste kapacitivne, rezistivne, akustične, mehaničkeili optičke strukture. U posljednje dvije decenije sve više se koristenanostrukturni ugljenični materijali, posebno grafen. Pored grafenaveliku pažnju u mnogim oblastima od elektronike do senzora jeprivukao grafen-oksid (Graphene-oxide - GO). Štampana elektronikasve više postaje vodeća tehnologija u izradi senzora. Pored jeftineizrade i aditivnih procesa sa smanjenom infrastrukturom, prednostištampane tehnologije su komponente male mase, savitljive,transparentne, tanke, komponente koje se mogu ugraditi u/na garderobui nositi, kao i proizvodnja velikog broja komponenti. U poslednjihnekoliko godina roboti se sve više uključuju u ljudski život, što jedovelo do potrebe za usavršavanjem u oblasti robotike. LJudi saokruženjem komuniciraju pomoću četiri čula: dodira, sluha, vida iukusa. Čulo dodira ljudima omogućava da dohvate različite predmete,podignu ih, obavljaju različite zadatke, itd. Iz tog razloga je razvojsenzora dodira, odnosno senzora koji bi se ugradili u robotske prste,od veoma velikog značaja. Kao jedna vrsta takvih senzora su otporničkisenzori sile (Force Sensing Resistors - FSR). Kod ovih senzora dolazido promjene otpornosti ukoliko se na sensor djeluje određenom silom.
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Sharma, Manoj Kumar. "Design and Fabrication of Intention Based Upper-Limb Exoskeleton." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1462290841.
Full textBooks on the topic "Force based design (FBD)"
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Gunzel, Charles A. FSR based force torque transducer design. Naval Postgraduate School, 1993.
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Chikurov, Nikolay, and Nikolay Levizi. Construction of discrete-logical control systems for electroautomatics. INFRA-M Academic Publishing LLC., 2023. http://dx.doi.org/10.12737/1852441.
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The textbook discusses engineering methods of analysis and synthesis of discrete logic control systems of industrial mechanisms based on the apparatus of logic algebra and cyclograms of the operation of these mechanisms. New methods have been developed that make it possible to synthesize complex control systems on various element bases fairly quickly. Examples of designing control systems for machine-tool electrical automation devices are given. Students master the methodology of programming logic controllers in the instrumental programming environment of the ISaGRAF 6.5 ASP version using the FBD functional block language.
 Meets the requirements of the federal state educational standards of higher education of the latest generation.
 For students of mechanical engineering specialties, researchers, as well as specialists involved in the design of discrete logic control systems for various industrial mechanisms.
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Tang, Man-Chung. The Story of the Koror Bridge. International Association for Bridge and Structural Engineering (IABSE), 2014. http://dx.doi.org/10.2749/cs001.
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<p>Koror Babeldaob Bridge, also called Koror Babelthuap Bridge or simply Koror Bridge, connects the islands of Koror and Babeldaob in the Republic of Palau. The design of the bridge began in 1974 and was based on the prevailing AASHO Standard Specifications at that time and was supplemented by ACI and CEB-FIP design recommendations on an as-needed basis. When the Koror Bridge was opened to traffic in April 1977, it was the world's longest concrete girder span. A few years later, the bridge began to deflect more than had been anticipated. The owner commissioned a Japanese engineering firm in 1985 and then a US engineering firm in 1993 to conduct in-depth investigations of the structure. Both firms came to the same conclusion that the bridge was structurally safe and that the excessive deflection was an unexplainable phenomenon. Nevertheless, in order to improve the driving quality of the bridge deck, the owner decided to repair the bridge. The repair scheme made changes to the structural system and added a large amount of post-tensioning force to the bridge. Unfortunately, less than three months after the repair, late in the afternoon on 26 September, 1996,nineteen and a half years after it was opened to traffic, the bridge collapsed. Thereafter, most of the documents were sealed as a result of litigation between the various parties and the debris was cleared. For a long time, it was impossible to study the facts surrounding the bridge's collapse. Only recently, through continuous probing by a group of engineers, were these documents made accessible to researchers.</p>
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National Aeronautics and Space Administration (NASA) Staff. Design and Flight Evaluation of a New Force-Based Flow Angle Probe. Independently Published, 2018.
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Structured simulation-based training program for a digitized force: Approach, design, and functional requirements. U.S. Army Research Institute for the Behavioral and Social Sciences, 1999.
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Structured simulation-based training program for a digitized force: Approach, design, and functional requirements. U.S. Army Research Institute for the Behavioral and Social Sciences, 1999.
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Bahadur, Issam Bait. Integration of resonant force sensors into a passive microgripper for robotic based three-dimensional microassembly: Design and modelling. 2006.
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Halliday, Daniel. Inheritance of Wealth. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198803355.001.0001.
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This book presents a philosophical analysis of inherited wealth: it examines both the moral foundations of the right to bequeath wealth and the case for restricting that right with an inheritance tax. The book seeks to approach inheritance as a challenge with much contemporary significance but draws on ideas from the history of political philosophy. The positive proposals that emerge count as a sort of hybrid between luck egalitarian and social egalitarian conceptions of justice, with some sensitivity to utilitarian and libertarian insights. Chapter 1 lays out the main arguments and motivations in brief. Chapters 2 and 3 survey a variety of arguments from the eighteenth to the early twentieth century, with a view to establishing which insights have enduring force. Chapters 4, 5, and 6 assemble an egalitarian case for restricting inherited wealth, though many particular egalitarian conceptions are rejected. The main positive point to emerge in these chapters is that unrestricted inheritance is unjust to the extent that it enables and enhances the intergenerational replication of inequality. Here, inequality is understood in a group-based sense: the unjust effects of inheritance are principally in its tendency to concentrate certain opportunities into certain groups. This results in economic segregation. Concern about this tendency represents a modification of a somewhat stronger but less precise concern about the role of inheritance in perpetuating class hierarchy. Chapters 7 and 8 engage, somewhat more piecemeal, with arguments from the libertarian tradition and with certain questions about the design of taxation schemes.
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Laurenson, Sarah. The Material Landscapes of Scotland’s Jewellery Craft, 1780–1914. Bloomsbury Publishing Plc, 2023. http://dx.doi.org/10.5040/9781501357978.
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Jewellery is used to adorn the human body, to mark wealth and status, and to build and mark personal and emotional ties between individuals. The role of goldsmiths and jewellers in manipulating materials to fuse symbolic and monetary value in precious and deeply meaningful objects has seen their skill command a high level of respect across time and place. Yet the making of jewellery during the modern era has received very little scholarly attention. The Material Landscapes of Scotland’s Jewellery Craft, 1780-1914 challenges the tired but persistent notion that industrialization, by replacing the human hand with the machine, destroyed skilled craftsmanship by exploring the neglected but rich area of Scotland’s jewellery craft during the long 19th century. It demonstrates that industrialization was, in fact, the driving force behind a deeper engagement with hand skill and nature that is more closely associated with goldsmiths of the early modern period. The book explores the material, visual and symbolic dimensions to jewellery through a craft-based reading that considers these sources by fusing social and cultural history methods with approaches drawn from art, design and dress history. The making and wearing of jewellery are considered as embodied cultural practices throughout, forging a new methodological approach that can be applied more widely to the study of material things. By placing producers and their skill in cultural context, the book reveals how attending to the materiality of even the smallest of objects can offer new and multifaceted insights into the wider transformations that marked British history during the long 19th century. With its focus on the relationship between materials, making processes and the social and cultural meanings of things, the book offers a novel approach to the history of material culture.
Book chapters on the topic "Force based design (FBD)"
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Li, Tianliang, Guanyi Wang, Xue Han, and Yuegang Tan. "An FBG-Based Clamping Force Sensor for Intervertebral Foraminoscopic Surgery." In Advances in Mechanical Design. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-0922-9_162.
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Prajapati, Shiv Kumar, Payal Kesharwani, Nishi Mody, Ankit Jain, and Swapnil Sharma. "Formulation by Design (FbD)." In Micro- and Nanotechnologies-Based Product Development. CRC Press, 2021. http://dx.doi.org/10.1201/9781003043164-2.
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Papagiannopoulos, George A., George D. Hatzigeorgiou, and Dimitri E. Beskos. "Force-Based Design of EC8." In Seismic Design Methods for Steel Building Structures. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-80687-3_3.
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Choudhury, Satyabrata. "Force-Based Design and its Limitations." In Performance-Based Seismic Design of Structures. CRC Press, 2024. http://dx.doi.org/10.1201/9781003441090-1.
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Menon, Devdas, A. Meher Prasad, and Jiji Anna Varughese. "Seismic Design Philosophy: From Force-Based to Displacement-Based Design." In Advances in Indian Earthquake Engineering and Seismology. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-76855-7_13.
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Baranyi, Péter. "Impedance Control for Force Reflecting Telemanipulation." In TP-Model Transformation-Based-Control Design Frameworks. Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-19605-3_16.
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Li, Hao, Weifeng Gao, Changhua Jiang, et al. "Modeling of Human Elbow Joint Force Based on MVT Test." In Cross-Cultural Design. Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-35946-0_36.
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Yao, Jiantao, Yulei Hou, Hang Wang, and Yongsheng Zhao. "Isotropic Design of Stewart Platform-Based Force Sensor." In Intelligent Robotics and Applications. Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-88518-4_78.
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Zhu, Hongyuan, Xiaoxiong Liu, YueHang Zhang, and Yu Li. "Design of Carrier-Based Aircraft Landing Control Law Based on Direct Force." In Lecture Notes in Electrical Engineering. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8155-7_96.
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Biradar, Bapugouda B., Anoop I. Shirkol, and Sitara U. Guled. "Seismic Evaluation of RC Frame Designed by Force-Based Design and Direct Displacement-Based Design Methods." In Proceedings of 17th Symposium on Earthquake Engineering (Vol. 2). Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1604-7_21.
Full textConference papers on the topic "Force based design (FBD)"
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He, Xiang, Yong Liu, Cheng Liu, and Sihan Cheng. "Based on FPGA 3D force sensor data acquisition system design." In Fifth International Conference on Computer Communication and Network Security (CCNS 2024), edited by Zhiyong Xiong and Zhaolong Ning. SPIE, 2024. http://dx.doi.org/10.1117/12.3038238.
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Shao, Jinggan, Hongtao Jiao, Yingsheng Ni, et al. "Design of Parallel Force Measurement Loading System Based on ANSYS." In 2024 International Conference on Intelligent Computing and Next Generation Networks (ICNGN). IEEE, 2024. https://doi.org/10.1109/icngn63705.2024.10871821.
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Murari, Krishna, Harvinder Singh, and Savleen Takkar. "Performance-based methodology for seismic assessment of code- conforming RC buildings." In IABSE Congress, Christchurch 2021: Resilient technologies for sustainable infrastructure. International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/christchurch.2021.1079.
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<p>The current Indian code for seismic design of structures is based on the force-based design (FBD) philosophy but the damage is more related to strain and displacement rather than strength. Also, structures can’t be designed for target design objectives by FBD method under a specified hazard level. Hence it became necessary to develop new codes and standards based on more robust design methodology to overcome the various shortcomings. The paper presents the results of a study conducted to evaluate the effect of provisions mandated by BIS design guidelines on the performance of a multi-storeyed building in event of a seismic activity. The performance of the building was evaluated on the parameters given in the FEMA guidelines. It was observed that the RC buildings designed as per Indian standard is found to be under-utilized and its overstrength ratio is observed to be of order two, leading to uneconomical design as compared to the building designed according to Performance based methodology for achieving a similar value of the performance level.</p>
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Zhu, Jiaxiang, Guangbo Hao, Tinghao Liu, and Haiyang Li. "Design and Nonlinear Analysis of an Overconstraint Based Constant Amplification Ratio Compliant Mechanism." In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-89555.
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Abstract Compliant mechanism based amplifiers have been extensively studied with particular attentions to achieving a high amplification ratio. However, a constant amplification ratio is less investigated, which is much desired for a simple and quick prediction of outputs. In this research, we aim to address this need. Thereby, we present an overconstraint based constant amplification ratio compliant mechanism (OCARCM) that alleviates the change of the amplification ratio. Comparative analysis is provided between the proposed OCARCM and the widely-used bridge-type compliant amplifier in terms of the ability to remain constant amplification ratio with and without payload. The free-body diagram (FBD) combined with the beam constraint model (BCM) method is employed to obtain the closed-form solutions that accurately and insightfully elaborate the nonlinearities in the force-displacement characteristics of the OCARCM. The closed-form results are verified by the nonlinear finite element results (FEA) with a maximum error of 1%. Both models reveal that the amplification ratio of the proposed OCARCM decreases by 1%, while the amplification ratio of the bridge-type amplifier decreases by approximately 14% under the same conditions. An experiment based on the 3D-printed prototype is conducted, which provides some insights into the characteristics of the design and the potential for future improvement.
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Jiang, Qi, Fangfang Gao, Yibin Li, Xuewen Rong, and Chengjin Zhang. "Design and research of wrist force sensor based on FBG." In 2013 IEEE International Conference on Information and Automation (ICIA). IEEE, 2013. http://dx.doi.org/10.1109/icinfa.2013.6720329.
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Song, Xin, Guannan Zheng, and Guowei Yang. "A Robust Aerodynamic Optimization Design for Airfoil Based on Interval Uncertainty Analysis Method." In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5426.
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Abstract Uncertainties will make aircraft deviate from the designed condition, resulting in the decrease in aerodynamic performance and even destruction. This paper presents a fast nonlinear interval analysis method considering geometric uncertainties. DFFD method is used to parameterize the airfoil shape, and the Kriging model for aerodynamic force and uncertainty variables is optimized by PSO algorithm to find the upper and lower bounds of the objective interval. The effects of geometric uncertainties on NACA0012 airfoil are analyzed using the above method. And then, a robust optimization design method is established based on the interval analysis method. FFD method is used to produce the deterministic design variables and the order relation of interval number is employed to transform the uncertain optimization to deterministic multi-objective optimization which is solved by MOPSO based on Pareto entropy. The robust optimization design is implemented for the symmetrical airfoil with the drag objective under geometric uncertainties and thickness constraint, and the results are compared with the deterministic optimization to validate the effectiveness of the developed method.
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Devaragudi, Sai Rajeev, and Bo Chen. "MPC-Based Control of Autonomous Vehicles With Localized Path Planning for Obstacle Avoidance Under Uncertainties." In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97712.
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Abstract This paper presents a Model Predictive Control (MPC) approach for longitudinal and lateral control of autonomous vehicles with a real-time local path planning algorithm. A heuristic graph search method (A* algorithm) combined with piecewise Bezier curve generation is implemented for obstacle avoidance in autonomous driving applications. Constant time headway control is implemented for a longitudinal motion to track lead vehicles and maintain a constant time gap. MPC is used to control the steering angle and the tractive force of the autonomous vehicle. Furthermore, a new method of developing Advanced Driver Assistance Systems (ADAS) algorithms and vehicle controllers using Model-In-the-Loop (MIL) testing is explored with the use of PreScan®. With PreScan®, various traffic scenarios are modeled and the sensor data are simulated by using physics-based sensor models, which are fed to the controller for data processing and motion planning. Obstacle detection and collision avoidance are demonstrated using the presented MPC controller.
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Miyanawala, Tharindu Pradeeptha, Yulong Li, Yun Zhi Law, and Harrif Santo. "Deep Learning Based Prediction of Hydrodynamic Forces on Offshore Platforms." In ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-104748.
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Abstract Irregular ocean waves cause fluctuating non-linear hydrodynamic forces on the body, which is an importance factor to account for in offshore and marine applications. While physical experimental and computational techniques provide valuable physics insight, they are generally time-consuming and expensive for design space exploration. We present an efficient Long Short Time Memory (LSTM) based deep-learning technique to predict unsteady hydrodynamic forces on slender bodies, where drag forces are more dominant than inertia forces. A leaky non-linear rectification is employed to approximate the mapping between surface elevation time series and hydrodynamic (drag) force time series. The deep neural network is fed with irregular waves based on JONSWAP spectrum as the input and the target data generated by the full-order Navier-Stokes computations using a generic offshore jack-up platform. The LSTM is trained using a stochastic gradient descent method to predict time series of the hydrodynamic forces on the jack-up and the results are compared with the full-order computations. Within the error threshold, the predictions based on our deep convolutional network have a speed-up of nearly 2 orders of magnitude compared to the full-order results and consume an insignificant fraction of computational resources. Overall, the proposed LSTM-based approximation procedure has the potential to be used for parametric design and digital twinning of jack-up platforms.
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Bandi, Punit, James P. Schmiedeler, and Andrés Tovar. "Design of Crashworthy Structures With Controlled Energy Absorption in the HCA Framework." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-71391.
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This work presents a novel method for designing crashworthy structures with controlled energy absorption based on the use of compliant mechanisms. This method helps in introducing flexibility at desired locations within the structure, which in turn reduces the peak force at the expense of a reasonable increase in intrusion. For this purpose, the given design domain is divided into two subdomains: flexible (FSD) and stiff (SSD) subdomains. The design in the flexible subdomain is governed by the compliant mechanism synthesis approach for which output ports are defined at the interface between the two subdomains. These output ports aid in defining potential load paths and help the user make better use of a given design space. The design in the stiff subdomain is governed by the principle of a fully-stressed design for which material is distributed to achieve uniform energy distribution within the design space. Together, FSD and SSD provide for a combination of flexibility and stiffness in the structure, which is desirable for most crash applications.
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Miyanawala, T. P., and Rajeev K. Jaiman. "A Novel Deep Learning Method for the Predictions of Current Forces on Bluff Bodies." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78338.
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Unsteady separated flow behind a bluff body causes fluctuating drag and transverse forces on the body, which is of great significance in many offshore and marine engineering applications. While physical experimental and computational techniques provide valuable physics insight, they are generally time-consuming and expensive for design space exploration and flow control of such practical scenarios. We present an efficient Convolutional Neural Network (CNN) based deep-learning technique to predict the unsteady fluid forces for different bluff body shapes. The discrete convolution process with a non-linear rectification is employed to approximate the mapping between the bluff-body shape and the fluid forces. The deep neural network is fed by the Euclidean distance function as the input and the target data generated by the full-order Navier-Stokes computations for primitive bluff body shapes. The convolutional networks are iteratively trained using a stochastic gradient descent method to predict the fluid force coefficients of different geometries and the results are compared with the full-order computations. We have extended this CNN-based technique to predict the variation of force coefficients with the Reynolds number as well. Within the error threshold, the predictions based on our deep convolutional network have a speed-up nearly three orders of magnitude compared to the full-order results and consumes an insignificant fraction of computational resources. The deep CNN-based model can predict the hydrodynamic coefficients required for the well-known Lighthill’s force decomposition in almost real time which is extremely advantageous for offshore applications. Overall, the proposed CNN-based approximation procedure has a profound impact on the parametric design of bluff bodies and the feedback control of separated flows.
Reports on the topic "Force based design (FBD)"
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Michel, Kenan. Performance Based Seismic Design of Lateral Force Resisting System. University of California, San Diego, 2020. http://dx.doi.org/10.25368/2020.126.
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Mohr. L52241 Strain-Based Design - Strain Concentration at Girth Welds. Pipeline Research Council International, Inc. (PRCI), 2006. http://dx.doi.org/10.55274/r0010386.
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Strain-based design is used for many situations for pipelines where the loadings from forces other than the internal pressure can be the largest generators of stress and strain in the pipe wall. Such loadings can be generated by soil subsidence, frost heave, thermal expansion and contraction, landslides, pipe reeling, pipe laying, and several other types of environmental loading. Designing based on strain for these cases has an advantage over designing based on stress because these loadings tend to apply a given displacement rather than a given force to the pipe. Standards are much better developed for stress-based design than for strain-based design. While several standards are available that have some coverage of strain-based design, there is a tendency to cover only limited types of loading, as in API RP 1111 for offshore pipe laying. This program aimed to improve guidelines for strain-based design of pipelines by studying cases with combinations of internal pressure and axial plastic strain in tension. Softened heat-affected zone (HAZ) regions have been observed to concentrate strain, particularly under internal pressure. HAZ softening has been observed for welds on X-70 and X-80 steels. Cases with little or no softening have also been observed for other welds in these same grades. This project extended these findings to X-100 steels, with cases of obvious softening and little or no softening observed. Higher heat inputs and larger weld volumes per pass associated with submerged arc welding (SAW) as compared to gas metal arc welding (GMAW) have been correlated with greater softening in each of these pipe grades.
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Fernandez, Ruben, Hernando Lugo, and Georfe Dulikravich. Aerodynamic Shape Multi-Objective Optimization for SAE Aero Design Competition Aircraft. Florida International University, 2021. http://dx.doi.org/10.25148/mmeurs.009778.
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The SAE Regular Class Aero Design Competition requires students to design a radio-controlled aircraft with limits to the aircraft power consumption, take-off distance, and wingspan, while maximizing the amount of payload it can carry. As a result, the aircraft should be designed subject to these simultaneous and contradicting objectives: 1) minimize the aerodynamic drag force, 2) minimize the aerodynamic pitching moment, and 3) maximize the aerodynamic lift force. In this study, we optimized the geometric design variables of a biplane configuration using 3D aerodynamic analysis using the ANSYS Fluent. Coefficients of lift, drag, and pitching moment were determined from the completed 3D CFD simulations. Extracted coefficients were used in modeFRONTIER multi-objective optimization software to find a set of non-dominated (Pareto-optimal or best trade-off) optimized 3D aircraft shapes from which the winner was selected based to the desired plane performance.
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Waisner, Scott, Victor Medina, Charles Ellison, et al. Design, construction, and testing of the PFAS Effluent Treatment System (PETS), a mobile ion exchange–based system for the treatment of per-, poly-fluorinated alkyl substances (PFAS) contaminated water. Engineer Research and Development Center (U.S.), 2022. http://dx.doi.org/10.21079/11681/43823.
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Poly-,Per-fluorinated alkyl substances (PFAS) are versatile chemicals that were incorporated in a wide range of products. One of their most important use was in aqueous film-forming foams for fighting liquid fuel fires. PFAS compounds have recently been identified as potential environmental contaminants. In the United States there are hundreds of potential military sites with PFAS contamination. The ERDC designed and constructed a mobile treatment system to address small sites (250,000 gallons or less) and as a platform to field test new adsorptive media. The PFAS Effluent Treatment System (PETS) has cartridge filters to remove sediments and a granular activated carbon (GAC) media filter to remove organic compounds that might compete with PFAS in the ion exchange process, although it may also remove PFAS too. The last process is an ion exchange resin specifically designed to remove PFAS to a target level of 70 ng/L or less (equivalent to the US Environmental Protection Agency (EPA) Drinking Water Health Advisory). The system was tested at Hurlburt Field, a US Air Force facility in Florida and at Naval Support Activity (NSA) Mid-South in Millington, TN.
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Warke. L51822 A Limit States and Reliability-Based Girth Weld Assessment Framework for Long Pipeline Segments. Pipeline Research Council International, Inc. (PRCI), 2000. http://dx.doi.org/10.55274/r0011242.
Full textAbstract:
This report describes the development of a graphical framework enabling probabilistic assessment of surface-breaking planar defects in pipeline girth welds, in terms of multivariate limit state functions incorporating weld strength mismatch effects. This is part of an ongoing effort by the Welding Research Supervisory Committee to align girth weld fitness-for-service assessment methods with recent advancements in limit states- and reliability-based design for pipelines. A previous three-year program (PR-185-9429) by the same investigators produced a database of partial safety factors (PSFs), calibrated against a broad range of reliability targets, for use with limit state functions based on existing stress intensity (crack driving force) and plastic collapse solutions. Several inherent limitations of these solutions, including their inability to account for strength mismatch in the behavior of weld metal and heat-affected zone (HAZ) flaws, motivated the development of new relationships in the present work. The PSF-based approach to probabilistic assessment also had its limitations, namely that it did not provide all of the necessary tools to address multi-weld pipeline segments, and that it was somewhat cumbersome to apply in practice. A more direct method was therefore desired.
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Nosenko, Yuliya H., Maiia V. Popel, and Mariya P. Shyshkina. The state of the art and perspectives of using adaptive cloud-based learning systems in higher education pedagogical institutions (the scope of Ukraine). [б. в.], 2019. http://dx.doi.org/10.31812/123456789/3246.
Full textAbstract:
The article deals with the problems of using adaptive cloud-based learning systems (ACLS) in the modern high-tech educational environment and expanding access to them as tools of educational and research activity at higher education pedagogical institutions in Ukraine. The conceptual apparatus of cloud-based adaptive learning systems application and design is considered; their main characteristics are revealed; the ways of their pedagogical application are described. The experience of Institute of Information Technologies and Learning Tools of NAES of Ukraine on designing and applying of the cloud-based learning and research environment is outlined. The results of the survey of 31 higher education pedagogical institutions on using ACLS are presented. It is established that in the near future ACLS will become the driving force behind the development of new pedagogy, new strategies for personalizing education, and expanding opportunities for active learning.
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Gunay, Selim, Fan Hu, Khalid Mosalam, et al. Blind Prediction of Shaking Table Tests of a New Bridge Bent Design. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, 2020. http://dx.doi.org/10.55461/svks9397.
Full textAbstract:
Considering the importance of the transportation network and bridge structures, the associated seismic design philosophy is shifting from the basic collapse prevention objective to maintaining functionality on the community scale in the aftermath of moderate to strong earthquakes (i.e., resiliency). In addition to performance, the associated construction philosophy is also being modernized, with the utilization of accelerated bridge construction (ABC) techniques to reduce impacts of construction work on traffic, society, economy, and on-site safety during construction. Recent years have seen several developments towards the design of low-damage bridges and ABC. According to the results of conducted tests, these systems have significant potential to achieve the intended community resiliency objectives. Taking advantage of such potential in the standard design and analysis processes requires proper modeling that adequately characterizes the behavior and response of these bridge systems. To evaluate the current practices and abilities of the structural engineering community to model this type of resiliency-oriented bridges, the Pacific Earthquake Engineering Research Center (PEER) organized a blind prediction contest of a two-column bridge bent consisting of columns with enhanced response characteristics achieved by a well-balanced contribution of self-centering, rocking, and energy dissipation. The parameters of this blind prediction competition are described in this report, and the predictions submitted by different teams are analyzed. In general, forces are predicted better than displacements. The post-tension bar forces and residual displacements are predicted with the best and least accuracy, respectively. Some of the predicted quantities are observed to have coefficient of variation (COV) values larger than 50%; however, in general, the scatter in the predictions amongst different teams is not significantly large. Applied ground motions (GM) in shaking table tests consisted of a series of naturally recorded earthquake acceleration signals, where GM1 is found to be the largest contributor to the displacement error for most of the teams, and GM7 is the largest contributor to the force (hence, the acceleration) error. The large contribution of GM1 to the displacement error is due to the elastic response in GM1 and the errors stemming from the incorrect estimation of the period and damping ratio. The contribution of GM7 to the force error is due to the errors in the estimation of the base-shear capacity. Several teams were able to predict forces and accelerations with only moderate bias. Displacements, however, were systematically underestimated by almost every team. This suggests that there is a general problem either in the assumptions made or the models used to simulate the response of this type of bridge bent with enhanced response characteristics. Predictions of the best-performing teams were consistently and substantially better than average in all response quantities. The engineering community would benefit from learning details of the approach of the best teams and the factors that caused the models of other teams to fail to produce similarly good results. Blind prediction contests provide: (1) very useful information regarding areas where current numerical models might be improved; and (2) quantitative data regarding the uncertainty of analytical models for use in performance-based earthquake engineering evaluations. Such blind prediction contests should be encouraged for other experimental research activities and are planned to be conducted annually by PEER.
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Zhou. L52284 Upheaval Buckling Limit State Function for Onshore Gas Pipelines. Pipeline Research Council International, Inc. (PRCI), 2008. http://dx.doi.org/10.55274/r0010669.
Full textAbstract:
For buried pipelines a well established problem has been that of upheaval buckling. This occurs because the fluid is usually pumped through the pipes at elevated temperatures causing the pipeline to experience thermal expansion which, if restrained, leads to an increase in the axial stress in the pipeline possibly resulting in a buckling failure. A secondary phenomenon that has also been identified, particularly in loose sands and silts, involves floatation of pipelines through the backfill material, usually shortly after burial. The upheaval buckling limit state function developed in this project employs the critical upheaval buckling force and applied compressive force due to temperature and pressure. It applies to pipe sections containing a hill-crest type of imperfection over which the pipeline is routed using a series of cold formed bends. The critical buckling force is calculated using an empirical equation developed by Boreas based on the results of parametric finite element analyses (FEA) on 252 design cases. The input parameters for the empirical equation are pipe diameter, diameter-over-wall-thickness (D/t) ratio, grade, pressure, soil download and imperfection angle. The development of the equation is described in a technical report prepared by Boreas.
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Aji, Muhammad Habibullah Galih Tri, Jing Zhang, Naoya Wada, Jian Pu, Kensuke Fukushi, and Gheeta Mohan. Safeguarding South-East Asia's Marine Ecosystems from Ocean Acidification Threats. United Nations University Institute for the Advanced Study of Sustainability, 2025. https://doi.org/10.53326/ywmh3810.
Full textAbstract:
The increasing carbon dioxide emissions from human activities are being absorbed by the oceans, leading to a decrease in seawater pH levels worldwide. South-East Asia is particularly vulnerable to this problem, as the projected trend of ocean acidification severely threatens marine life in the region, as well as marine industry productivity and food safety. Urgent action must be taken by the Association of Southeast Asian Nations (ASEAN) Secretariat and its Member States to sustain coastal populations’ livelihoods and economic prosperity. Recommendations: • Improve marine protected areas (MPAs) by applying science-based design and grass-roots community participation • Establish a regional task force and collaborative funding • Increase public awareness and implement marine educational programmes through curriculum integration
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Limtrakul, Sunun, and Wiwut Tanthapanichakoon. Modeling and simulation of flows in two-phase fluidized systems. The Thailand Research Fund, 1999. https://doi.org/10.58837/chula.res.1999.57.
Full textAbstract:
This present work aims to investigate the solids motion and fluid flow in a two phase fluidized bed via a discrete particle modeling and simulation. The motion of individual particle is based on the fluid force acting on the particle and the contact force between particles. The contact force is models by using the same analogy of spring, dash-pot and friction slider. In addition, the mixing and segregation in beds containing two types of particles with different densities and different size are also studies. Moreover, the effects of superficial gas velocity and bad geometry on the solids movements are also investigated. A solids circulation cell is found when the bed reaches at steady state. The solids ascend at the center with high velocity and descend with low velocity near the wall. The simulation solids flow pattern agrees well with the experimental result obtain by Moslemian (1987). The solids distributions in the bed containing the particles with the density ratios of 1.4 and 1.25 show good mixing. On the other hand the bed with the particle density ratio of 2.5 shows segregating behavior. Similarly, the beds containing the particles with the size ratios of 1.33 and 2.0 show mixing behavior and segregating behavior, respectively. These results obtained from simulation were found to follow the mixing/degregation criteria obtained experimentally by Tanaka et al. (1996). The solids mixing and segregation are not significantly dependent on the superficial gas velocity. The findings of the simulation i.e., solids movement and distribution will be information for understanding the hydrodynamics, mass and heat transfer leading to successfully design and operation of the system. The knowledge of this modeling and simulation is applicable to study the phenomena in the system concerned with granular materials such as multiphase flow reactor and dryer.