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Pal, Ujjwal, Ying-Chieh Liu, and Amaresh Chakrabarti. "Evaluating FuncSION: A software for automated synthesis of design solutions for stimulating ideation during mechanical conceptual design." Artificial Intelligence for Engineering Design, Analysis and Manufacturing 28, no. 3 (July 22, 2014): 209–26. http://dx.doi.org/10.1017/s0890060414000183.
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AbstractThe goal of the work reported in this paper is to use automated, combinatorial synthesis to generate alternative solutions to be used as stimuli by designers for ideation. FuncSION, a computational synthesis tool that can automatically synthesize solution concepts for mechanical devices by combining building blocks from a library, is used for this purpose. The objectives of FuncSION are to help generate a variety of functional requirements for a given problem and a variety of concepts to fulfill these functions. A distinctive feature of FuncSION is its focus on automated generation of spatial configurations, an aspect rarely addressed by other computational synthesis programs. This paper provides an overview of FuncSION in terms of representation of design problems, representation of building blocks, and rules with which building blocks are combined to generate concepts at three levels of abstraction: topological, spatial, and physical. The paper then provides a detailed account of evaluating FuncSION for its effectiveness in providing stimuli for enhanced ideation.
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Rojas, T. C., J. M. de la Fuente, A. G. Barrientos, S. Penadés, L. Ponsonnet, and A. Fernández. "Gold Glyconanoparticles as Building Blocks for Nanomaterials Design." Advanced Materials 14, no. 8 (April 18, 2002): 585. http://dx.doi.org/10.1002/1521-4095(20020418)14:8<585::aid-adma585>3.0.co;2-w.
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Neuendorf, Talika A., Niclas Weigel, Michelle Vigogne, and Julian Thiele. "Additive Soft Matter Design by UV-Induced Polymer Hydrogel Inter-Crosslinking." Gels 8, no. 2 (February 14, 2022): 117. http://dx.doi.org/10.3390/gels8020117.
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In recent years, stimuli-responsive hydrogels have gained tremendous interest in designing complex smart 4D materials for applications ranging from biomedicine to soft electronics that can change their properties on demand over time. However, at present, a hydrogel’s response is often induced by merely a single stimulus, restricting its broader applicability. The controlled hierarchical assembly of various hydrogel building blocks, each with a tailored set of mechanical and physicochemical properties as well as programmed stimulus response, may potentially enable the design and fabrication of multi-responsive polymer parts that process complex operations, like signal routing dependent on different stimuli. Since inter-connection stability of such building blocks directly accompanies the transmission of information across building blocks and is as important as the building property itself to create complex 4D materials, we provide a study on the utility of an inter-crosslinking mechanism based on UV-induced 2,3-dimethylmaleimide (DMMI) dimerization to inter-connect acrylamide-based and N-isopropylacrylamide-based millimeter-sized cubic building blocks, respectively. The resulting dual-crosslinked assemblies are freestanding and stable against contraction–expansion cycles in solution. In addition, the approach is also applicable for connecting microfluidically fabricated, micrometer-sized hydrogel spheres, with the resulting assemblies being processable and mechanical stable, likewise resisting contraction–expansion in different solvents, for instance.
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Ou, Feng-Ming, Hong-Sen Yan, and Ming-Feng Tang. "THE SYNTHESIS OF MECHANISM SYSTEMS USING A MECHANISM CONCEPT LIBRARY." Transactions of the Canadian Society for Mechanical Engineering 34, no. 1 (March 2010): 151–63. http://dx.doi.org/10.1139/tcsme-2010-0010.
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This paper presents an approach for synthesizing all possible mechanism systems of kinematic building blocks in a mechanism concept library. The kinematic building blocks are defined as SISO primitive mechanisms, and their serial and/or parallel combinations are expressed as corresponding out-trees based on graph representation. By representing the constructive building blocks as labeled vertices and their possible combination relationships as directed edges, the synthesis approach is developed by adopting graph enumeration theorem. An illustrative example of four kinematic building blocks, including two crank-rocker linkages and two slider-crank mechanisms, is provided to validate the presented approach. The result shows that all feasible mechanism systems can be obtained effectively by following the synthesis method and which provides more alternatives in the library during design or re-design of mechanisms.
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Kim, Charles J., Sridhar Kota, and Yong-Mo Moon. "An Instant Center Approach Toward the Conceptual Design of Compliant Mechanisms." Journal of Mechanical Design 128, no. 3 (July 29, 2005): 542–50. http://dx.doi.org/10.1115/1.2181992.
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As with conventional mechanisms, the conceptual design of compliant mechanisms is a blend of art and science. It is generally performed using one of two methods: topology optimization or the pseudo-rigid-body model. In this paper, we present a new conceptual design methodology which utilizes a building block approach for compliant mechanisms performing displacement amplification/attenuation. This approach provides an interactive, intuitive, and systematic methodology for generating initial compliant mechanism designs. The instant center is used as a tool to construct the building blocks. The compliant four-bar building block and the compliant dyad building block are presented as base mechanisms for the conceptual design. It is found that it is always possible to obtain a solution for the geometric advantage problem with an appropriate combination of these building blocks. In a building block synthesis, a problem is first evaluated to determine if any known building blocks can satisfy the design specifications. If there are none, the problem is decomposed to a number of sub-problems which may be solved with the building blocks. In this paper, the problem is decomposed by selecting a point in the design space where the output of the first building block coincides with the second building block. Two quantities are presented as tools to aid in the determination of the mechanism's geometry – (i) an index relating the geometric advantage of individual building blocks to the target geometric advantage and (ii) the error in the geometric advantage predicted by instant centers compared to the calculated value from FEA. These quantities guide the user in the selection of the location of nodes of the mechanism. Determination of specific cross-sectional size is reserved for subsequent optimization. An example problem is provided to demonstrate the methodology's capacity to obtain good initial designs in a straightforward manner. A size and geometry optimization is performed to demonstrate the viability of the design.
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Binti Katman, Herda Yati, Wong Jee Khai, Omrane Benjeddou, and Nuha Mashaan. "Experimental Investigation of a New Design of Insulation Gypsum Plaster Blocks." Buildings 12, no. 9 (August 24, 2022): 1297. http://dx.doi.org/10.3390/buildings12091297.
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Green building materials are an alternative to ordinary materialsoffering multiple environmental benefits. This study consists of an experimental investigation of a new design of gypsum plaster blocks. First, a mix design of gypsum plaster and water mixture was prepared. The optimal mix composition was determined according to the mechanical and physical properties, such as the water absorption, the temperature of hydration, the density, and the compressive strength of different gypsum plaster and water mixtures made by varying the water dosage. The second part of this investigation aims to study a new design of green blocks prepared from the optimal water and gypsum plaster mixture. The new blocks are perforated to lighten them and to reduce their thermal conductivity in order to make them moreinsulate. Experimental tests were conducted on the block prototype, such as the measurement of dimensional tolerances, compressive strength, density, flatness, water absorption, residual moisture, surface hardness, and thermal conductivity. Experimental test results show that the new blocks have very low density, and their compressive strength is sufficient for wall construction. In addition, the manufacturing process of the new blocks is very easy and very fast. Finally, the obtained physical and mechanical properties of the new gypsum plaster blocks give it the opportunity to be used for interior walls for building constructions.
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Caponetto, Rosa, Massimo Cuomo, Maurizio Detommaso, Giada Giuffrida, Antonio Lo Presti, and Francesco Nocera. "Performance Assessment of Giant Reed-Based Building Components." Sustainability 15, no. 3 (January 22, 2023): 2114. http://dx.doi.org/10.3390/su15032114.
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The growing concern for the reduction of energy needs and the environmental impact of the building sector has placed emphasis on the possibilities offered by natural materials. The adoption of agricultural by-products seems to be promising and in line with the circular economy paradigm. Materials such as hemp and straw have been extensively adopted in contemporary construction, but nevertheless, the potential use of giant reed has not been sufficiently investigated despite being a common infesting plant abundantly available all over the planet. This work focuses on the performances assessment of lime/cement–reeds mixtures as base materials to design a new line of building components (bricks, blocks, panels and loose insulation) that can be used both in new bio-based construction and in existing buildings for energy-efficiency retrofit. The main materials used in the experimental campaign are giant reed by-products, lime, cement and local and recycled aggregates. The evaluation of the physical, mechanical and thermal properties of lime–reed and cement–reed composites are presented. The results of thermal conductivities (between 0.245 and 0.191 W/m K) and mechanical properties (compressive strengths between 0.848 and 1.509 MPa, and flexural strengths between 0.483 and 0.829 MPa) allow meeting the requirements for non-bearing and thermal building blocks. The outcomes show how blocks made with the abovementioned lime–reed mixture have good mechanical performance and thermo-physical behavior when compared to conventional building materials such as hollow clay or hemp blocks with the same thickness.
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Jin, Eunji, In Seong Lee, Dongwook Kim, Hosoowi Lee, Woo-Dong Jang, Myung Soo Lah, Seung Kyu Min, and Wonyoung Choe. "Metal-organic framework based on hinged cube tessellation as transformable mechanical metamaterial." Science Advances 5, no. 5 (May 2019): eaav4119. http://dx.doi.org/10.1126/sciadv.aav4119.
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Mechanical metamaterials exhibit unusual properties, such as negative Poisson’s ratio, which are difficult to achieve in conventional materials. Rational design of mechanical metamaterials at the microscale is becoming popular partly because of the advance in three-dimensional printing technologies. However, incorporating movable building blocks inside solids, thereby enabling us to manipulate mechanical movement at the molecular scale, has been a difficult task. Here, we report a metal-organic framework, self-assembled from a porphyrin linker and a new type of Zn-based secondary building unit, serving as a joint in a hinged cube tessellation. Detailed structural analysis and theoretical calculation show that this material is a mechanical metamaterial exhibiting auxetic behavior. This work demonstrates that the topology of the framework and flexible hinges inside the structure are intimately related to the mechanical properties of the material, providing a guideline for the rational design of mechanically responsive metal-organic frameworks.
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Cestari, Sibele Piedade, Peter Martin, Paul Hanna, Mark Kearns, and Luis Claudio Mendes. "Rotational-Moulded Building Blocks for the Circular Economy." Materials Science Forum 1042 (August 10, 2021): 17–22. http://dx.doi.org/10.4028/www.scientific.net/msf.1042.17.
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Throughout the combination of unique approaches on innovative polymer composites and rotational moulding plastics processing technique, we developed a building block using a mix of recycled and virgin plastic. This block was a technical case study from a multidisciplinary approach - comprising materials science, polymers processing and design - to reinsert recycled plastics in the Circular Economy. The aim was to produce a three-dimensional interlockable block, combining unique design and unconventional materials to create an emblematic building element. We investigated the composition and availability of local plastic waste, as well as other waste-stream materials – concrete waste, red mud, hemp fibre, sugarcane bagasse. We prepared a range of composites and blends to test their prospective aspect and processability. To simulate the end-result of a rotationally-moulded part, we prepared samples of the blends in an oven. The thermal analysis showed that all materials were thermally stable at the processing temperature of the virgin polymer in rotomoulding, around 200 °C. There were an evident LLDPE continuous-phase and a recyclate dispersed-phase. We also explored the aesthetic effect of scattering particles of colour in the mixes. The impact test showed better results for the polyethylene-based recyclates if compared to polypropylene and poly (ethylene terephthalate) ones. We concluded that waste materials could be revalued into something practical and reproducible, produced by rotational moulding plastics processing. And we developed a viable and innovative potential product for the Circular Economy, requiring minimal fixing and no further external finishing.
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Ling, Bowen, and Ilenia Battiato. "Module-Fluidics: Building Blocks for Spatio-Temporal Microenvironment Control." Micromachines 13, no. 5 (May 14, 2022): 774. http://dx.doi.org/10.3390/mi13050774.
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Generating the desired solute concentration signal in micro-environments is vital to many applications ranging from micromixing to analyzing cellular response to a dynamic microenvironment. We propose a new modular design to generate targeted temporally varying concentration signals in microfluidic systems while minimizing perturbations to the flow field. The modularized design, here referred to as module-fluidics, similar in principle to interlocking toy bricks, is constructed from a combination of two building blocks and allows one to achieve versatility and flexibility in dynamically controlling input concentration. The building blocks are an oscillator and an integrator, and their combination enables the creation of controlled and complex concentration signals, with different user-defined time-scales. We show two basic connection patterns, in-series and in-parallel, to test the generation, integration, sampling and superposition of temporally-varying signals. All such signals can be fully characterized by analytic functions, in analogy with electric circuits, and allow one to perform design and optimization before fabrication. Such modularization offers a versatile and promising platform that allows one to create highly customizable time-dependent concentration inputs which can be targeted to the specific application of interest.
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Caruso, Marco, Nicola Cefis, Giovanni Dotelli, Chiara Moletti, and Sergio Sabbadini. "Triaxial Tests on Hempcrete for Prefabricated Blocks Production." Key Engineering Materials 919 (May 11, 2022): 15–20. http://dx.doi.org/10.4028/p-lnca1j.
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Nature-based solutions are sustainable building materials produced recovering and enhancing agricultural biomasses which are by-products or waste of crops as, for example, rice, flax or hemp. Specifically, this research investigates the properties of hempcrete which is produced mixing lime, which acts as binder, and hemp shives, as vegetal aggregate. Hempcrete is characterized by breathability and excellent insulating properties, moreover it is a sustainable material due to the introduction of vegetal material and due to the carbonation of lime which gives further carbon dioxide sequestration. The mechanical properties of the material are largely variable and, in this research, triaxial tests have been performed to evaluate this experimental methodology as a technique applicable to evaluate the mechanical behavior of this material. The tests have been performed on samples produced with the same mix design developed by an Italian manufacturer for the production of prefabricated hempcrete blocks. These building components are used as non-loadbearing blocks, they are introduced in building envelopes or in indoor partition walls as insulating elements.
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Egan, I., J. M. Ritchie, and P. D. Gardiner. "Measuring performance change in the mechanical design process arena." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 219, no. 12 (December 1, 2005): 851–63. http://dx.doi.org/10.1243/095440505x32724.
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Measurement of the design process is an issue facing business and academic practitioners alike. This paper outlines an approach used to formalize design process measurement within a large electromechanical original equipment manufacturer (OEM) by applying a derivation of the Carnegie-Mellon/Software Engineering Institute systems engineering capability maturity model(R) (SE-CMM(R)), entitled the process capability model-mechanical design (PCM-MD). This new model was created using a similar structure and format of questions as the SE-CMM(R), with modifications to suit mechanical engineering terminology. This was then applied to the mechanical engineering design department of the partner company where it was successfully piloted and then reapplied to produce a picture of how the effectiveness or otherwise of the processes associated with their multidisciplinary mechanical design function altered over time. This work provided the building blocks for further detailed studies to be carried out at other sites in the same company and within the mechanical engineering departments of other firms.
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GUO, QIAOHANG, HUANG ZHENG, WENZHE CHEN, and ZI CHEN. "FINITE ELEMENT SIMULATIONS ON MECHANICAL SELF-ASSEMBLY OF BIOMIMETIC HELICAL STRUCTURES." Journal of Mechanics in Medicine and Biology 13, no. 06 (December 2013): 1340018. http://dx.doi.org/10.1142/s0219519413400186.
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Helices are ubiquitous building blocks in natural systems, and have since become major sources of inspiration for engineering design of helical devices with a range of applications in sensors, transducers, transistors and micro-robotics devices. In this work, we illustrate the mechanical self-assembly principle in spontaneous helical structures, and perform finite element simulations to model such large deformation of thin structures in three dimensions. Our work can facilitate designs of tunable helical structures at both macroscopic and microscopic scales with desirable geometric parameters for engineering applications such as in nanoelectromechanical systems (NEMS), drug delivery, sensors, acturators, optoelectronics and microbotics.
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Zhao, Xiaolin, Zhongli Hu, Yining Li, Youwei Wang, Erhong Song, Li Zhang, and Jianjun Liu. "Assembling organic–inorganic building blocks for high-capacity electrode design." Materials Horizons 8, no. 6 (2021): 1825–34. http://dx.doi.org/10.1039/d1mh00128k.
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Rzhevutskaya, V. A., and Yu G. Moskalkova. "Analysis of the functional efficiency of enclosing structures made of expanded clay concrete." Vesnik of Yanka Kupala State University of Grodno. Series 6. Engineering Science 12, no. 2 (November 24, 2022): 78–90. http://dx.doi.org/10.52275/2223-5396-2022-12-2-78-90.
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The introduction discusses the main advantages and disadvantages of the use of structural and structural insulated lightweight concrete in the manufacture of load-bearing structures of buildings based on an analytical review of the work of various researchers. It is demonstrated that in the Republic of Belarus there is a sufficient production base for the mass production of expanded clay and expanded clay concrete products. For the special case of designing load-bearing walls made of expanded clay concrete blocks considered in the article, the features of their design are given (for example, reinforced concrete belt, reinforcement of masonry with grids). In the main part, on the example of the design of load-bearing external walls of a warehouse building, the achieved economic effect is demonstrated by the calculation method based on variant design. The results of the practical calculation performed within the framework of the variant design of the enclosing load-bearing walls of the building are presented. Two options are considered: the traditional solution is a masonry of silicate bricks with a thickness of 380 mm, an alternative option is a masonry of expanded clay concrete blocks with a thickness of 300 mm. It is established that the economic effect of the use of expanded clay concrete blocks is 9.3 % per 1 cubic meter. walls compared to the masonry of silicate bricks without taking into account the positive effect in the selection of foundation blocks and slabs, which is achieved as a result of reducing the own weight of the walls. The ways to improve the physical and mechanical characteristics of expanded clay concrete are proposed: the use of expanded clay gravel as a coarse aggregate, increase the strength of expanded clay gravel at the stage of its production, the use of expanded clay fraction up to 10 mm, and fiber reinforcement by polypropylene fiber. In conclusion, it is stated that the use of expanded clay concrete products made of structural and heat-insulating concrete can improve the indicators of the functional efficiency of building structures.
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Fogarasy, A. A., and M. R. Smith. "A New Simplified Approach to the Kinematic Analysis and Design of Epicyclic Gearboxes." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 209, no. 1 (January 1995): 49–53. http://dx.doi.org/10.1243/pime_proc_1995_209_121_02.
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The present paper introduces a much simplified method for the kinematic analysis of epicyclic gear drives. It is based on the concept of the existence of only two basic building blocks and their kinematic constraint equations. These can easily be found by inspection of the relevant kinematic structural diagram. A new type of notation is used which is simpler and more versatile than those of previous methods and is adaptable to depicting the kinematic alternatives of any particular drive without the need for drawing structural diagrams.
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Moniruzzaman, Md, Christopher O'Neal, Ariful Bhuiyan, and Paul F. Egan. "Design and Mechanical Testing of 3D Printed Hierarchical Lattices Using Biocompatible Stereolithography." Designs 4, no. 3 (July 6, 2020): 22. http://dx.doi.org/10.3390/designs4030022.
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Emerging 3D printing technologies are enabling the rapid fabrication of complex designs with favorable properties such as mechanically efficient lattices for biomedical applications. However, there is a lack of biocompatible materials suitable for printing complex lattices constructed from beam-based unit cells. Here, we investigate the design and mechanics of biocompatible lattices fabricated with cost-effective stereolithography. Mechanical testing experiments include material characterization, lattices rescaled with differing unit cell numbers, topology alterations, and hierarchy. Lattices were consistently printed with 5% to 10% lower porosity than intended. Elastic moduli for 70% porous body-centered cube topologies ranged from 360 MPa to 135 MPa, with lattices having decreased elastic moduli as unit cell number increased. Elastic moduli ranged from 101 MPa to 260 MPa based on unit cell topology, with increased elastic moduli when a greater proportion of beams were aligned with the loading direction. Hierarchy provided large pores for improved nutrient transport and minimally decreased lattice elastic moduli for a fabricated tissue scaffold lattice with 7.72 kN/mm stiffness that is suitable for bone fusion. Results demonstrate the mechanical feasibility of biocompatible stereolithography and provide a basis for future investigations of lattice building blocks for diverse 3D printed designs.
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Zach, Jiri, Martin Sedlmajer, and Jitka Hroudová. "Development of Building Elements with Thermal Insulation Filler Based on Secondary Raw Materials." Advanced Materials Research 649 (January 2013): 147–50. http://dx.doi.org/10.4028/www.scientific.net/amr.649.147.
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With increasing requirements for properties of envelope design in respect of thermal protection of buildings also requirements for building material properties have been growing. In case of ceramic shaped pieces for peripheral structures the way to further improvement of its thermal insulation properties is quite difficult. Generally thickness of interior groins can be reduced and its geometrical layout changed or the ceramics blocks dimensions increased and thus width of the masonry construction. Use of insulation filler integrated in block cavities is the alternative technology of production of insulation special shapes of high insulation properties. In these cases the ceramic fragment ensures the mechanical stability of the block and integrated insulation layer in smaller or bigger part (depending on its part) the thermal properties and eventually also the acoustic and insulation ones. The paper describes application possibilities of insulation materials based upon waste textile fibres as integrated layer in current masonry ceramic blocks of high utility properties.
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Jiang, Wei, Hua Ma, Mingde Feng, Leilei Yan, Jiafu Wang, Jun Wang, and Shaobo Qu. "Origami-inspired building block and parametric design for mechanical metamaterials." Journal of Physics D: Applied Physics 49, no. 31 (July 19, 2016): 315302. http://dx.doi.org/10.1088/0022-3727/49/31/315302.
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Raorane, Paras, Bhagyesh Rathod, Shubham Raut, Sahil Sankpal, and Nilesh Shinde. "Automated Engine Design using Machine Learning." International Journal for Research in Applied Science and Engineering Technology 11, no. 4 (April 30, 2023): 2845–51. http://dx.doi.org/10.22214/ijraset.2023.50788.
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Abstract: Machine Learning has been widely used in solving complex problems across various fields for the past decade, and computers have become more powerful than ever before. Mechanical engineers have a responsibility to use these groundbreaking discoveries to improve existing instruments and methodologies for better efficiency in production. Technologies like Machine Learning, Deep Learning, and Computer Vision can automate complex design procedures and can be integrated with existing technologies to create the building blocks for the 5th industrial revolution. Computerized programs can be helpful in situations where resources like time and skilled labor are scarce. The project aims to use Machine Learning and other Python-based frameworks to develop an interactive interface for designing complex models, specifically a combustion engine.
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Papadopoulos, E., and Ahmed Abu-Abed. "A DESIGN METHODOLOGY FOR ZERO REACTION ROBOTS." Transactions of the Canadian Society for Mechanical Engineering 19, no. 3 (September 1995): 197–211. http://dx.doi.org/10.1139/tcsme-1995-0009.
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In many applications of advanced robotic systems, reaction forces and moments transmitted by a manipulator to its base are highly undesirable. Such reactions reduce the accuracy of high-speed manipulators, destroy zero-g environments in space, require the use of thruster fuel to stabilize free-flying space robots, or excite suspension modes in mobile robotic systems. In this paper, we analyze the problem of force and torque transmission in robotic systems, and propose design and planning methods that can reduce it, or eliminate it. It is shown that designing a force-balanced manipulator with an invariant mass matrix, and employing appropriate trajectory planning, can result in reactionless motions. Two redundant planar manipulator designs, that can be used as building blocks of more complicated systems, demonstrate the usefulness of the proposed methods. An important advantage of these methods is that if reactionless behavior is not needed, system redundancy can be recovered.
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Ruan, Xiao Li, Jie Jie Li, Xiao Ke Song, Hong Jian Zhou, Wei Xing Yuan, Wen Wang Wu, and Re Xia. "Mechanical Design of Antichiral-Reentrant Hybrid Intravascular Stent." International Journal of Applied Mechanics 10, no. 10 (December 2018): 1850105. http://dx.doi.org/10.1142/s1758825118501053.
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Chiral and reentrant metastructures with auxetic deformation abilities can serve as the building blocks in many industrial applications because of their light weight, high specific strength, energy absorption properties. In this paper, we report an innovative tubular-like structure by a combined mechanical effect of antichiral and reentrant. 2D antichiral-reentrant hybrid structures consisting of circular nodes and tangentially-connected ligaments are predesigned and fabricated using laser cutting technology with high-resolution. The elastic properties and auxeticity of the plane structure are analyzed and compared based on finite element analysis (FEA) and experimental results. For the first time, the antichiral-reentrant hybrid intravascular stents with the auxetic feature are proposed and parametric models are devised with good geometrical structure demonstrated. A series of large-scale stents are manufactured with stereolithography apparatus (SLA) additive manufacturing technique, and their mechanical behaviors are investigated in both experimental tests and FEA. As the selected antichiral-reentrant hybrid stents with tailored expansion ability are subjected to radial loading by the dilation of the balloon, stents undergo identifiable deformation mechanism due to the beam-like ligaments and circular node elements in the varied geometrical design, resulting in the distinct stress outcomes in plaque. It is also demonstrated that the antichiral-reentrant hybrid stents with tunable auxeticity possess robust mechanical properties through implantation inside the obstructed lesion.
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Ludford, Paul, Fikret Aydin, and Meenakshi Dutt. "Design and Characterization of Nanostructured Biomaterials via the Self-assembly of Lipids." MRS Proceedings 1498 (2013): 233–38. http://dx.doi.org/10.1557/opl.2013.342.
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ABSTRACTWe are interested in designing nanostructured biomaterials using nanoscopic building blocks such as functionalized nanotubes and lipid molecules. In our earlier work, we summarized the multiple control parameters which direct the equilibrium morphology of a specific class of nanostructured biomaterials. Individual lipid molecules were composed of a hydrophilic head group and two hydrophobic tails. A bare nanotube encompassed an ABA architecture, with a hydrophobic shaft (B) and two hydrophilic ends (A). We introduced hydrophilic hairs at one end of the tube to enable selective transport through the channel. The dimensions of the nanotube were set to minimize its hydrophobic mismatch with the lipid bilayer. We used a Molecular Dynamics-based mesoscopic simulation technique called Dissipative Particle Dynamics which simultaneously resolves the structure and dynamics of the nanoscopic building blocks and the hybrid aggregate. The amphiphilic lipids and functionalized nanotubes self-assembled into a stable hybrid vesicle or a bicelle in the presence of a hydrophilic solvent. We showed that the morphology of the hybrid structures was directed by factors such as the temperature, the rigidity of the lipid molecules, and the concentration of the nanotubes. Another type of hybrid nanostructured biomaterial could be multi-component lipid bilayers. In this paper, we present approaches to design hybrid nanostructured materials using multiple lipid species with different chemistries and molecular chain stiffness.
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Xu, Zhenyu, Yongsen Zhou, Baoping Zhang, Chao Zhang, Jianfeng Wang, and Zuankai Wang. "Recent Progress on Plant-Inspired Soft Robotics with Hydrogel Building Blocks: Fabrication, Actuation and Application." Micromachines 12, no. 6 (May 24, 2021): 608. http://dx.doi.org/10.3390/mi12060608.
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Millions of years’ evolution has imparted life on earth with excellent environment adaptability. Of particular interest to scientists are some plants capable of macroscopically and reversibly altering their morphological and mechanical properties in response to external stimuli from the surrounding environment. These intriguing natural phenomena and underlying actuation mechanisms have provided important design guidance and principles for man-made soft robotic systems. Constructing bio-inspired soft robotic systems with effective actuation requires the efficient supply of mechanical energy generated from external inputs, such as temperature, light, and electricity. By combining bio-inspired designs with stimuli-responsive materials, various intelligent soft robotic systems that demonstrate promising and exciting results have been developed. As one of the building materials for soft robotics, hydrogels are gaining increasing attention owing to their advantageous properties, such as ultra-tunable modulus, high compliance, varying stimuli-responsiveness, good biocompatibility, and high transparency. In this review article, we summarize the recent progress on plant-inspired soft robotics assembled by stimuli-responsive hydrogels with a particular focus on their actuation mechanisms, fabrication, and application. Meanwhile, some critical challenges and problems associated with current hydrogel-based soft robotics are briefly introduced, and possible solutions are proposed. We expect that this review would provide elementary tutorial guidelines to audiences who are interested in the study on nature-inspired soft robotics, especially hydrogel-based intelligent soft robotic systems.
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Padilla, Moises, Manuel Servin, Guillermo Garnica, and Gonzalo Paez. "Design of robust phase-shifting algorithms using N-step formulas as building blocks." Optics and Lasers in Engineering 121 (October 2019): 346–51. http://dx.doi.org/10.1016/j.optlaseng.2019.04.025.
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Kota, Sridhar, and Shean-Juinn Chiou. "Conceptual design of mechanisms based on computational synthesis and simulation of kinematic building blocks." Research in Engineering Design 4, no. 2 (June 1992): 75–87. http://dx.doi.org/10.1007/bf01580146.
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Pedroti, Leonardo Gonçalves, S. N. Monteiro, C. M. Vieira, and J. Alexandre. "Properties and Microstructure of Clay Ceramics with Granite Waste for Press-Molded Structural Block." Materials Science Forum 727-728 (August 2012): 809–14. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.809.
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Extrusion of a clay body is the most applied process in the ceramic industries for manufacturing structural blocks. Nowadays, the assembly of such blocks through a fitting system is gaining attention owing to the saving in material and reducing in the cost of the building construction. However, this fitting system requires a press-molding, rather than extrusion, to allow blocks to be fabricated with different shapes. In this work, the ideal composition of clay bodies incorporated with granite powder waste was investigated for the production of press-molded ceramic blocks. An experimental design was applied to determine the optimum properties and microstructures. Press load of 15 ton and temperatures from 850 to 1050°C were considered. The results indicated that mechanical strength of 30 MPa and water absorption of 15% could be attained with the incorporation of up to 17% of granite powder waste.
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Krishna, Gamidi, Ramesh Devarapalli, Garima Lal, and C. Reddy. "Design of Mechanically Flexible Organic Crystals: A Crystal Engineering Approach." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C648. http://dx.doi.org/10.1107/s2053273314093516.
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Utilization of organic single crystal materials is increasing day by day owing to their promising applications in organic light emitting diodes [1], organic solar cells, mechanochromic luminescence [2] and tablatability [3] of APIs etc. These desirable functions, especially mechanical properties, can be achieved by imparting soft nature in organic materials, however unfortunately there is no simple strategy to attain this. Till date all the findings are serendipitous discoveries, so a rational design strategy is necessary to accomplish such soft mechanical behavior in molecular crystals. Here we propose a design strategy to attain plastically deformable organic materials by introducing slip planes in the crystal structures. The high plasticity can be achieved by introducing hydrophobic groups, such as t-Bu, -OMe, -Me and multiple –Cl (or) –Br groups on -Ar building blocks, for example on naphthalene diimide (NDI), which leads to the formation of slip planes in the crystal structures (as shown in attached figure), hence facilitate the plastic (irreversible) bending [2].
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Hao, Guangbo, and Haiyang Li. "Conceptual designs of multi-degree of freedom compliant parallel manipulators composed of wire-beam based compliant mechanisms." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 3 (May 15, 2014): 538–55. http://dx.doi.org/10.1177/0954406214535925.
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This paper proposes conceptual designs of multi-degree(s) of freedom (DOF) compliant parallel manipulators (CPMs) including 3-DOF translational CPMs and 6-DOF CPMs using a building block based pseudo-rigid-body-model (PRBM) approach. The proposed multi-DOF CPMs are composed of wire-beam based compliant mechanisms (WBBCMs) as distributed-compliance compliant building blocks (CBBs). Firstly, a comprehensive literature review for the design approaches of compliant mechanisms is conducted, and a building block based PRBM is then presented, which replaces the traditional kinematic sub-chain with an appropriate multi-DOF CBB. In order to obtain the decoupled 3-DOF translational CPMs (XYZ CPMs), two classes of kinematically decoupled 3-PPPR (P: prismatic joint, R: revolute joint) translational parallel mechanisms (TPMs) and 3-PPPRR TPMs are identified based on the type synthesis of rigid-body parallel mechanisms, and WBBCMs as the associated CBBs are further designed. Via replacing the traditional actuated P joint and the traditional passive PPR/PPRR sub-chain in each leg of the 3-DOF TPM with the counterpart CBBs (i.e. WBBCMs), a number of decoupled XYZ CPMs are obtained by appropriate arrangements. In order to obtain the decoupled 6-DOF CPMs, an orthogonally-arranged decoupled 6-PSS (S: spherical joint) parallel mechanism is first identified, and then two example 6-DOF CPMs are proposed by the building block based PRBM method. It is shown that, among these designs, two types of monolithic XYZ CPM designs with extended life have been presented.
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Zhang, Z., and A. O. Krushynska. "Programmable shape-morphing of rose-shaped mechanical metamaterials." APL Materials 10, no. 8 (August 1, 2022): 080701. http://dx.doi.org/10.1063/5.0099323.
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Shape morphing is one of the most attractive functionalities of materials that are desired in many applications, including robotic grippers, medical stents, wearable electronics, and so on. Shape morphing can be implemented by using mechanical metamaterials that combine building blocks with properly designed mechanical or material properties. The design approaches are, however, mostly ad hoc or require materials with special properties. This work proposes two automated design strategies for programmable shape morphing and validates them on structures 3D-printed from a widely available commercial Stereolithography Durable resin. We proposed a so-called rose-shaped metamaterial with reduced stress concentration due to the absence of sharp corners and with a large range of tailorable Poisson’s ratios, from −0.5 to 0.9, governed by a single design parameter. We programmed the shape of the rose-shaped metamaterial sheets aiming at high shape comfortability or uniform effective stiffness. The shape-morphing performance is demonstrated in the linear (0.1% strain) and non-linear (20% strain) deformation regimes, and it agrees well with the tensile test results. Our findings show the potential to develop complex practical metamaterial structures at comparatively low costs.
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Robayo-Salazar, Rafael A., William Valencia-Saavedra, Sandra Ramírez-Benavides, Ruby Mejía de Gutiérrez, and Armando Orobio. "Eco-House Prototype Constructed with Alkali-Activated Blocks: Material Production, Characterization, Design, Construction, and Environmental Impact." Materials 14, no. 5 (March 8, 2021): 1275. http://dx.doi.org/10.3390/ma14051275.
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The interest of the construction industry in alkali-activated materials has increased to the extent that these materials are recognized as alternatives to ordinary Portland cement-based materials in the quest for sustainable construction. This article presents the design and construction of a prototype of an eco-friendly house built from concrete blocks produced using alkali activation technology or geopolymerization. The prototype meets the requirements of the current Colombian Regulations for Earthquake Resistant Buildings (NSR-10) and includes standards related to the performance of the materials, design, and construction method for earthquake-resistant confined masonry of one- or two-story buildings. The alkali-activated blocks were obtained from different precursors (aluminosilicates), including a natural volcanic pozzolan, ground granulated blast furnace slag, fly ash, construction and demolition waste (concrete, ceramic, brick, and mortar), and red clay brick waste. The physical-mechanical characterization of the alkali-activated blocks allowed their classification according to the structural specifications of the Colombian Technical Standard NTC 4026 (equivalent to ASTM C90). The global warming potential (GWP) or “carbon footprint” attributed to the raw materials of alkali-activated blocks was lower (25.4–54.7%) than that of the reference blocks (ordinary Portland cement concrete blocks). These results demonstrate the potential of alkali-activated materials for application in the construction of eco-friendly houses.
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Ciobanu, Marius, and Carmen-Simona Jordan. "Viologen capped by nucleobase—building blocks for functional materials: synthesis and structure–properties relationship." Journal of Materials Science 56, no. 35 (October 11, 2021): 19425–38. http://dx.doi.org/10.1007/s10853-021-06554-1.
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AbstractThe current study presents a new class of functional derivatives (1–3) consisting of a dicationic viologen (4,4’-bipyridinium unit) (V2+) capped by nucleobases thymine (NB1), adenine (NB2), thymine/adenine (NB1, NB2), and ion-paired with amphiphilic anion 3,4,5-tris(dodecyloxy)benzene sulfonate (DOBS−). The target of our work focuses on the design and synthesis of molecular building blocks in which three different functionalities are combined: chromophore (V2+ unit), molecular recognition (NB unit), and thermotropic liquid crystal (DOBS unit). The resulted materials exhibit liquid crystalline properties at ambient temperature with significant particularities-induced by nucleobases in the mesogen structure. Structure–properties relationship study focuses on providing knowledge about (1) how the thermotropic, redox properties, thermochromism, or ionic conductive properties are influenced by the presence of purinic or pyrimidinic nucleobases, and (2) how effective is their ability to self-assembly by hydrogen bonding in nonpolar solvents. The presence of nucleobases has been proved to have a substantial impact on electron transfer rate during the reduction of viologen moieties by intermolecular aggregation. Ionic conductivity and thermochromic properties of derivatives 1–3 were investigated and compared to a non-containing nucleobase analog methyl viologen with 3,4,5-tris(dodecyloxy)benzene sulfonate anion (MV) as reference. Graphical abstract
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Wang, Xudong. "Piezoelectric Nanogenerators for Mechanical Energy Harvesting." International Symposium on Microelectronics 2011, no. 1 (January 1, 2011): 000367–75. http://dx.doi.org/10.4071/isom-2011-tp5-paper3.
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Piezoelectric ZnO nanowires (NWs) have recently been demonstrated as a promising concept to harvest micro- and nano-scale mechanical energy from the surroundings. It is named nanogenerator. The operation principle relies on the bending of NWs by an external disturbance which creates piezoelectric potential along the deformed surfaces. The piezoelectric potential was predicted to be hundreds of milivolts per NW and the optimal power output per NW could reach a few nanowatts when it is under resonant oscillation. The first nanogenerator prototype was fabricated with vertically aligned ZnO NW arrays that were placed beneath a zigzag-shaped metal electrode with a small gap. In this design, all the NWs can be actuated simultaneously and continuously by ultrasonic waves, leading to the production of a continuous DC current. A textile fiber based nanogenerator has been developed for harvesting low-frequency vibration/friction energies. A piezoelectric thin film based nanogenerator was demonstrated to convert low-speed wind energy into electricity through the stimulated oscillation. These devices have the potential to fundamentally improve the mechanical energy harvesting capability with advanced nanostructure building blocks and compact designs, which might eventually lead to an effective power source for self-powered electronic systems with higher energy density, higher efficiency, longer life time, as well as lower cost.
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Zhou, Tiegang, Xin Wang, Ben Ma, Zaiyu Zhang, and Wei Tan. "Seismic performance of new adobe bricks masonry: Design and experiment." Advances in Structural Engineering 25, no. 2 (October 25, 2021): 277–89. http://dx.doi.org/10.1177/13694332211046349.
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At present, adobe houses with traditional characteristics are still widely used in rural areas in western China, but their seismic performance is relatively poor, and they often suffer serious damage under earthquake. To improve the seismic performance of traditional adobe buildings while retaining the characteristics of residential buildings, the mechanical properties of compressed earth blocks (CEB) were tested in this study, and the microstructure characteristics of CEB after failure were analyzed by electron microscope. On this basis, six adobe wall specimens were designed and tested by quasi-static loading to investigate the influence of core columns and different types of bricks on its seismic performance. The results show that the core column can improve the bearing capacity and shear capacity of hollow CEB, and it can also significantly increase the bearing capacity, energy dissipation capacity, and ductility of CEB wall. In general, the adobe wall with core columns shows excellent seismic performance, which can provide a new choice for improving the seismic performance of the adobe house.
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Sundaramurthy, Suresh, Shashi Bala, Anil Kumar Sharma, Jyoti Verma, Sasan Zahmatkesh, S. Arisutha, Sarika Verma, Mika Sillanpaa, Nagavinothini Ravichandran, and Balamurugan Panneerselvam. "Performance Evaluation of Environmentally Sustainable Precast Cement Concrete Paver Blocks Using Fly Ash and Polypropylene Fibre." Sustainability 14, no. 23 (November 25, 2022): 15699. http://dx.doi.org/10.3390/su142315699.
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Paver blocks are manufactured from zero-slump plain concrete, which is small element used for outdoor applications and flexible road surfaces. IS:15658 (2006) permits the use of 33- grade ordinary Portland cement (OPC) as the minimum for manufacturing paver blocks, but the usage of this type of cement is restricted in India nowadays. In this context, we have studied OPC 43-grade cement replaced by 30% Class F-grade fly ash and the addition of 0.0% and 0.5% polypropylene fibre (PPF) to evaluate the suitability of paver blocks in terms of the climatic conditions, movement of vehicles and road surfaces in India. The synergistic effect of the mechanical properties of paver blocks revealed that a 30% replacement of OPC with fly ash and 0.3% PPF is more suitable for the manufacturing of paver blocks. The obtained results from the reference mixes indicated that the mechanical properties of paver blocks have increased with respect to the age of the blocks. The present study is important for paver block manufacturers as it fulfils the mix design, strength and durability requirements for Indian roads associated with the utilization of waste materials such as fly ash. Additionally, the study will help the national economy increase by 20% in the future, along with the sustainability of virgin materials.
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Khan, Fahimullah, and Mohammad I. Younis. "RF MEMS electrostatically actuated tunable capacitors and their applications: a review." Journal of Micromechanics and Microengineering 32, no. 1 (December 8, 2021): 013002. http://dx.doi.org/10.1088/1361-6439/ac3cd5.
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Abstract This paper reviews the recent developments of micro-electromechanical system (MEMS) based electrostatically actuated tunable capacitors. MEMS based tunable capacitors (MBTCs) are important building blocks in advanced radio frequency communication systems and portable electronics. This is due to their excellent performance compared to solid state counterpart. Different designs, tuning mechanisms, and performance parameters of MBTCs are discussed, compared, and summarized. Several quantitative comparisons in terms of tuning range, quality factor (Q factor), and electrodes configurations are presented, which provide deep insight into different design studies, assists in selecting designs, and layouts that best suit various applications. We also highlight recent modern applications of tunable capacitors, such as mobile handsets, internet of things, communication sensors, and 5G antennas. Finally, the paper discusses different design approaches and proposes guidelines for performance improvement.
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Raposo, Patricia, André Furtado, António Arêde, Humberto Varum, and Hugo Rodrigues. "Mechanical characterization of concrete block used on infill masonry panels." International Journal of Structural Integrity 9, no. 3 (June 11, 2018): 281–95. http://dx.doi.org/10.1108/ijsi-05-2017-0030.
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Purpose The infill masonry walls in recent worldwide earthquakes have shown that it is necessary to conduct further studies to characterize the behavior of existing buildings and, in particular, of infill masonry walls under seismic activity. The lack of characterization studies of infill walls made by concrete blocks justifies the investigation reported herein, which includes experimental tests on sample sets to evaluate the mechanical properties of masonry components (units and mortar) and assemblages (wallets) made with masonry units from Faial. For the later, normal compressive, diagonal tensile/shear and out-of-plane flexural strengths were obtained according to standard procedures, the results of which are presented in the manuscript. The paper aims to discuss these issues. Design/methodology/approach One experimental campaign was conducted with the aim to mechanically characterize concrete blocks masonry samples. Several experimental tests were carried out in full-scale masonry concrete wallets according to the constructive methodology used. Findings Based on the data obtained from the mechanical characterization tests of the concrete masonry blocks, it can be seen that under simple compression, the masonry specimens’ average resistance is about 6 times superior than the average resistance to diagonal shear/tension, while the stiffness is almost doubled. In simple compression tests, it was observed that the masonry specimens cracked in areas of higher drilling of the blocks. In the tensile tests by diagonal compression, it was found that the test specimens were mainly fissured by the block/mortar joint interfaces, following the delineation of settlement and top joints. Originality/value There are no experimental results available in the literature for this type of bricks that can contribute to the development of numerical studies.
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Sagnelli, Domenico, Massimo Rippa, Amalia D’Avino, Ambra Vestri, Valentina Marchesano, and Lucia Petti. "Development of LCEs with 100% Azobenzene Moieties: Thermo-Mechanical Phenomena and Behaviors." Micromachines 13, no. 10 (October 3, 2022): 1665. http://dx.doi.org/10.3390/mi13101665.
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Azobenzene is one of the most investigated photo-responsive liquid crystalline molecules. It can isomerize between two different isoforms, trans (E) and cis (Z) configurations, when stimulated by light. It is used as a molecular engine in photo-mobile materials (PMPs). The use of liquid crystals (LCs) as building blocks enhances the mechanical properties of the PMPs. It is not easy to obtain PMPs with monodomain configurations when the LCs are 100% azobenzene. In this work, we studied three LC mixtures, describing the thermo/mechanical phenomena that regulate the actuation of such materials. The nematic temperature of the LC elastomers was measured and the PMPs carefully characterized for their bending and speed capability. Our finding suggests that the ratio between linear and cross-linker monomer greatly influences the nematic temperature of the mixture. Furthermore, 100% azobenzene materials polymerized using dicumyl peroxide can be useful to design polarization-selective switches.
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Dykstra, David M. J., Shahram Janbaz, and Corentin Coulais. "The extreme mechanics of viscoelastic metamaterials." APL Materials 10, no. 8 (August 1, 2022): 080702. http://dx.doi.org/10.1063/5.0094224.
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Mechanical metamaterials made of flexible building blocks can exhibit a plethora of extreme mechanical responses, such as negative elastic constants, shape-changes, programmability, and memory. To date, dissipation has largely remained overlooked for such flexible metamaterials. As a matter of fact, extensive care has often been devoted in the constitutive materials’ choice to avoid strong dissipative effects. However, in an increasing number of scenarios, where metamaterials are loaded dynamically, dissipation cannot be ignored. In this Research Update, we show that the interplay between mechanical instabilities and viscoelasticity can be crucial and that they can be harnessed to obtain new functionalities. We first show that this interplay is key to understanding the dynamical behavior of flexible dissipative metamaterials that use buckling and snapping as functional mechanisms. We further discuss the new opportunities that spatial patterning of viscoelastic properties offer for the design of mechanical metamaterials with properties that depend on the loading rate.
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Liu, Changxu, Ming Wu, Lijie Duan, Nan Yan, and Wei Jiang. "Hierarchical colloidosomes self-assembled from block copolymer micelles via emulsion interfacial confinement." Nanotechnology 33, no. 4 (November 3, 2021): 045603. http://dx.doi.org/10.1088/1361-6528/ac30f0.
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Abstract Hierarchical self-assembly of polymeric building blocks into high-level colloidosomes is desirable to not only design novel nanostructures but also fabricate the complex artificial materials across many length scales with multifunctionality. Although great progress has been made in the designing the hierarchical colloidosomes, the fabrication of polymeric colloidosomes self-assembled from block copolymer (BCP) colloidal nanoparticles still remains challenge. Here, we report the fabrication of the hierarchical polymeric colloidosomes with typical hollow internal structures self-assembled from the polystyrene-block-poly (2-vinyl pyridine) (PS-b-P2VP) BCP spherical micelles through the emulsion interfacial confinement, which is constructed through the water-in-1-butanol emulsion system. Moreover, the hierarchical colloidosomes can disassemble into the original uniform spherical micelles under the acid aqueous solution, indicating that the colloidosomes possess good pH stimuli-responsibility. Finally, the stability of the colloidosomes can be greatly improved by cross-linking the P2VP corona of original spherical micelles, offering the effective templates for construction of the multifunctional materials. This finding provides a simple yet effective method for the fabrication of the hierarchical colloidosomes from the BCP building blocks.
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Tiwari, Om Shanker, Sigal Rencus-Lazar, and Ehud Gazit. "Peptide- and Metabolite-Based Hydrogels: Minimalistic Approach for the Identification and Characterization of Gelating Building Blocks." International Journal of Molecular Sciences 24, no. 12 (June 19, 2023): 10330. http://dx.doi.org/10.3390/ijms241210330.
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Minimalistic peptide- and metabolite-based supramolecular hydrogels have great potential relative to traditional polymeric hydrogels in various biomedical and technological applications. Advantages such as remarkable biodegradability, high water content, favorable mechanical properties, biocompatibility, self-healing, synthetic feasibility, low cost, easy design, biological function, remarkable injectability, and multi-responsiveness to external stimuli make supramolecular hydrogels promising candidates for drug delivery, tissue engineering, tissue regeneration, and wound healing. Non-covalent interactions such as hydrogen bonding, hydrophobic interactions, electrostatic interactions, and π–π stacking interactions play key roles in the formation of peptide- and metabolite-containing low-molecular-weight hydrogels. Peptide- and metabolite-based hydrogels display shear-thinning and immediate recovery behavior due to the involvement of weak non-covalent interactions, making them supreme models for the delivery of drug molecules. In the areas of regenerative medicine, tissue engineering, pre-clinical evaluation, and numerous other biomedical applications, peptide- and metabolite-based hydrogelators with rationally designed architectures have intriguing uses. In this review, we summarize the recent advancements in the field of peptide- and metabolite-based hydrogels, including their modifications using a minimalistic building-blocks approach for various applications.
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Ye Wang, Jia, Ding Yuan Liu, Xiao Ming Chen, and T. C. Woo. "The Spanning Line Segments of a Polyhedron." Journal of Mechanical Design 118, no. 1 (March 1, 1996): 40–44. http://dx.doi.org/10.1115/1.2826854.
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In a polyhedron, it is observed that line segments arranged in a certain fashion preserve the intersection property: if intersection occurs with the polyhedron, the same also takes place with the line segments, and vice versa. Such line segments are said to be spanning the polyhedron which can be non-convex and non-simply connected. The properties of the spanning line segments in a polyhedron are introduced and an algorithm is presented based on “building blocks” with known solutions.
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Sharma, Tarun, Sandeep Singh, Shubham Sharma, Aman Sharma, Anand Kumar Shukla, Changhe Li, Yanbin Zhang, and Elsayed Mohamed Tag Eldin. "Studies on the Utilization of Marble Dust, Bagasse Ash, and Paddy Straw Wastes to Improve the Mechanical Characteristics of Unfired Soil Blocks." Sustainability 14, no. 21 (November 4, 2022): 14522. http://dx.doi.org/10.3390/su142114522.
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Earthen materials are the world’s oldest and cheapest construction materials. Compacted soil stabilised blocks are unfired admixed soil blocks made up of soil plus stabilisers such as binders, fibres, or a combination of both. The manufacturing and usage of cement and cement blocks raises a number of environmental and economic challenges. As a result, researchers are attempting to develop an alternative to cement blocks, and various tests on unfired admixed soil blocks have been performed. This investigation undertakes use of agricultural waste (i.e., paddy straw fiber and sugarcane bagasse ash) and industrial waste (i.e., marble dust) in manufacturing unfired admixed soil blocks. The applicability of unfired soil blocks admixed with marble dust, paddy straw fiber, and bagasse ash were studied. The marble dust level ranged from 25% to 35%, the bagasse ash content ranged from 7.5% to 12.5%, and the content of paddy straw fibre ranged from 0.8% to 1.2% by soil dry weight. Various tests were conducted on 81 mix designs of the prepared unfired admixed soil blocks to determine the mechanical properties of the blocks, followed by modeling and optimization. The characterization of the materials using XRD and XRF and of the specimens using SEM and EDS were performed for the mineral constituents and microstructural analysis. The findings demonstrate that the suggested method is a superior alternative to burned bricks for improving the mechanical properties of unfired admixed soil blocks.
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Chen, Si-Ming, Huai-Ling Gao, Yin-Bo Zhu, Hong-Bin Yao, Li-Bo Mao, Qi-Yun Song, Jun Xia, et al. "Biomimetic twisted plywood structural materials." National Science Review 5, no. 5 (July 30, 2018): 703–14. http://dx.doi.org/10.1093/nsr/nwy080.
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Abstract Biomimetic designs based on micro/nanoscale manipulation and scalable fabrication are expected to develop new-style strong, tough structural materials. Although the mimicking of nacre-like ‘brick-and-mortar’ structure is well studied, many highly ordered natural architectures comprising 1D micro/nanoscale building blocks still elude imitation owing to the scarcity of efficient manipulation techniques for micro/nanostructural control in practical bulk counterparts. Herein, inspired by natural twisted plywood structures with fascinating damage tolerance, biomimetic bulk materials that closely resemble natural hierarchical structures and toughening mechanisms are successfully fabricated through a programmed and scalable bottom-up assembly strategy. By accurately engineering the arrangement of 1D mineral micro/nanofibers in biopolymer matrix on the multiscale, the resultant composites display optimal mechanical performance, superior to many natural, biomimetic and engineering materials. The design strategy allows for precise micro/nanostructural control at the macroscopic 3D level and can be easily extended to other materials systems, opening up an avenue for many more micro/nanofiber-based biomimetic designs.
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Horst, Peter. "The significance of the interaction of stability and damage propagation in metallic and composite panels." International Journal of Structural Integrity 6, no. 6 (December 7, 2015): 737–58. http://dx.doi.org/10.1108/ijsi-11-2014-0065.
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Purpose – In general two main types of criteria are essential for the sizing of aircraft structural panels, namely, stability and damage tolerance. The way these criteria act and interact is very different for metallic and composite building blocks. While interaction of both types of criteria is relatively clear for composite parts, this is normally not the case for metallic ones. What is common for both is the fact that, if an interaction occurs, the impact is essential. The paper aims to discuss these issues. Design/methodology/approach – This is a survey paper. Findings – There is a strong mutual influence of buckling and damage in many cases. Originality/value – It shows the significance of both, buckling and damage as a combined phenomenon.
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M. Asyraf, M. R., Mohamad Ridzwan Ishak, S. M. Sapuan, N. Yidris, R. M. Shahroze, A. N. Johari, M. Rafidah, and R. A. Ilyas. "Creep test rig for cantilever beam: Fundamentals, prospects and present views." Journal of Mechanical Engineering and Sciences 14, no. 2 (June 23, 2020): 6869–87. http://dx.doi.org/10.15282/jmes.14.2.2020.26.0538.
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Cross arms in transmission tower are made up of Chengal wood, which degrade and collapse after a long period of service. This is due to creep deformation, and the rate of degradation is expedited due to exposure to extreme tropical climate. Hence, it is crucial to comprehend the early creep stage, which leads to structural failure. Apart from that, there are several research and industrial application gaps of these cross arms. For instance, creep life analysis of actual cross arms is still unexplored. In this study, the state-of-the-art is related to creep experiments and creep test rig designs, espacially on the creep test of a cantilever beam setup. The experimental methodologies implemented two vital approaches, conventional and accelerated techniques. The specific creep experiments on cantilever beam structure are emphasized and suggested in the manuscript as the building blocks for future design of cantilever creep test rig. This helps to guide future development design of cantilever beam creep test rig by fulfilling the specific criteria related to creep fundamentals, numerical modelling analysis, test operation for data evaluation, and development process. At the end, the challenges and improvements on the criteria existing design of test rigs are elaborated.
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Ludovico-Marques, Marco, and Carlos Chastre. "Prediction of Stress–Strain Curves Based on Hydric Non-Destructive Tests on Sandstones." Materials 12, no. 20 (October 15, 2019): 3366. http://dx.doi.org/10.3390/ma12203366.
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The study of the mechanical behavior of building stones is traditionally supported by destructive compression tests carried out on representative specimens. However, in order to respect the monuments’ integrity, the study of the mechanical behavior of stones can be based mostly on physical properties obtained from non-destructive tests (NDT). For this study, a simple and cheap NDT—water absorption under low pressure—was used to carry out fast surveys and to predict the most important design parameters of loadbearing masonry, among which are the compressive strength, strain at failure, and even elastic modulus on monument blocks. The paper presents the results of the experimental work conducted to obtain the physical properties and stress–strain curves of the sandstones tested. Supported by these results, it was possible to correlate the various parameters and develop an analytical model that predicts the stress–strain curve of the sandstones based on water absorption under low pressure tests. A good agreement is observed between the analytical model and the experimental tests.
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Wang, Siyi, Jiayang Wang, and Kyriakos Komvopoulos. "Mechanical Behavior of Bamboo-Like Structures under Transversal Compressive Loading." Biomimetics 8, no. 1 (March 5, 2023): 103. http://dx.doi.org/10.3390/biomimetics8010103.
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Inspired by many biological structures in nature, biomimetic structures demonstrate significantly better mechanical performance than traditional engineering structures. The exceptional mechanical properties of natural materials are attributed to the hierarchical architecture of their structure. Consequently, the implementation of biomimetic structures in the design of lightweight structures with tailored mechanical properties has been constantly increasing in many fields of science and engineering. The bamboo structure is of particular interest because it combines a light weight and excellent mechanical properties, often surpassing those of several engineering materials. The objective of this study was to evaluate the mechanical behavior of bamboo-inspired structures subjected to transversal compressive loading. Structures consisting of bamboo-like thin-walled hexagonal building blocks (unit cells) with different dimensions were fabricated by stereolithography 3D printing and their mechanical performance was evaluated by mechanical testing, high-speed camera video recordings, and finite element simulations. The results of the elastic modulus, yield strength, and strain energy density at fracture were interpreted in terms of characteristic dimensions of the unit cell structure. The failure process was elucidated in the light of images of the fractured structures and simulation strain maps. The results of this study demonstrate that ultralight bamboo-like structures with specific mechanical characteristics can be produced by optimizing the dimensions and number density of the hexagonal unit cell.
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Chillara, Venkata Siva C., Leon M. Headings, Ryohei Tsuruta, Eiji Itakura, Umesh Gandhi, and Marcelo J. Dapino. "Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts." Journal of Intelligent Material Systems and Structures 30, no. 3 (November 23, 2018): 479–94. http://dx.doi.org/10.1177/1045389x18812702.
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This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.
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Pisanty, Ben, Erdal Celal Oğuz, Cristiano Nisoli, and Yair Shokef. "Putting a spin on metamaterials: Mechanical incompatibility as magnetic frustration." SciPost Physics 10, no. 6 (June 8, 2021). http://dx.doi.org/10.21468/scipostphys.10.6.136.
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Mechanical metamaterials present a promising platform for seemingly impossible mechanics. They often require incompatibility of their elementary building blocks, yet a comprehensive understanding of its role remains elusive. Relying on an analogy to ferromagnetic and antiferromagnetic binary spin interactions, we present a general approach to identify and analyze topological mechanical defects for arbitrary building blocks. We underline differences between two- and three-dimensional metamaterials, and show how topological defects can steer stresses and strains in a controlled and non-trivial manner and can inspire the design of materials with hitherto unknown complex mechanical response.