Journal articles: 'Screws assembly'

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Suknikhom, Kampol, Pattaramon Jongpradist, Surachate Chutima, and Thoatsanope Kamnerdtong. "Effects of Screw Fastening Sequence to Top Cover Loosening in Hard Disk Drive Assembly." Applied Mechanics and Materials 110-116 (October 2011): 3534–40. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.3534.

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In hard disk drive assembly process, a number of small screws around the perimeter of the top cover are used to attach the top cover to the base. When one of the screws is fastened, screw loosening at the other screw heads can frequently be observed. . This research employs a three-dimensional finite element analysis to compare the effects of three different screw tightening sequences to top cover loosening in a 3.5-inch hard disk drive assembly. The top cover deformation and the contact forces at the screw heads of the three sequences are presented and discussed. Among the three sequences, the across pattern has shown to be the most appropriate sequence in which a minimum screw loosening occurs.

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Hermansson, Thomas O. "Quality assured tightening of screw joints." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 15 (August 9, 2016): 2588–94. http://dx.doi.org/10.1177/0954406215602038.

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Assembly of critical threaded connections such as safety belt and steering wheel screw joints must be quality assured to 100%. Not only the screw needs to be in position but the strength of the joint must also be guaranteed. To accomplish this, classical process surveillance is combined with angle monitoring and screws with special features. A plant system that keeps track on cars of various variants sends information to a screw joint controller that in turn sends a unique parameter set to the screw joint equipment. Together with so-called socket trays and balancing rules, the process arrangement can be made in such a way that the wrong screw can never be assembled without detection. To provide sufficient strength of joints, different kinds of angle monitoring are used. For example, entering/down running angle monitoring that are used to secure sufficient thread engagement with static high strength joints. Angle monitoring is also used to control that all parts are in position before the joint is tightened. For clamp load critical joints, final angle monitoring is used. Together with standard torques and standard assembly friction given by standard fasteners, sufficient clamping force can be guaranteed. With clamp load critical chassis joints, gradient-controlled yield point tightening has shown to be a successful assembly technique with the all new Volvo XC90. Furthermore, screws with special thread geometries are used to avoid cross threading, and in many cases hand entering can be taken away. Altogether, it can be concluded that the Volvo Cars assembly technology not only is very safe but also at a relatively low cost.

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Novotný, Lubomír W., Jiří Marek, and Tomáš Marek. "Issue of Rigidity of the Ball Screw Nut Exposed to Bending Stress during Bending Stress of the Ball Screw." Applied Mechanics and Materials 821 (January 2016): 372–77. http://dx.doi.org/10.4028/www.scientific.net/amm.821.372.

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Ball screws and nuts represent the inseparable part of machinetool building. The thread lead accuracy ranges in hundredths of millimetres per 1 m. In addition to the undesirable phenomena caused by heat (dilatability) and, e. g., torsional and transverse oscillations, the bending stress of the ball screw is considerably undesirable too. This stress and at the same time behaviour are transferred to the bending stress of the ball screw nut. This has a very harmful influence on setting of the ball screws, when the machine tool is assembled. Using the analysis by means of the FEM method, the paper conducts a survey of deformation issue of the arrangement "machine – ball screw – ball screw nut" during the assembly stage as well as a survey of compensation possibilities and other technical measures determined to limit the undesirable deformations and stress of the ball screw originating already in the manufacturing stage of the machine tool.

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Chien, Tsai-Po, Te-Hsin Yang, and Feng-Cheng Chang. "Flexural Performance of Built-Up Beams Made with Plantation Wood." Forests 10, no. 8 (August 1, 2019): 647. http://dx.doi.org/10.3390/f10080647.

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In this study, Japanese cedar (Cryptomeria japonica (L. f.) D. Don) harvested from a plantation in Taiwan was used to develop built-up beams using self-tapping screws as metal connectors and resorcinol formaldehyde resin as glue to assemble components based on various assembly configurations. Results showed that adding glue provided flexural rigidity, whereas assembly using self-tapping screws resulted in built-up beams with high ductility but relatively low flexural bearing capacity. Beams used glue exhibited approximately linear behavior, whereas those using only screws exhibited some undulating and stepwise responses, implying that shear force between the flanges and the web may cause buckling as well as the dislocation of the self-tapping screws. When using components of similar grades, adding another web can improve the performance. Furthermore, the grades of flanges can strongly influence the flexural load-bearing capacity. In addition, a smaller spacing between the screws can improve the flexural load-bearing performance, but also cause wooden components to crack. Typical bending failure modes were observed in the developed built-up beams, indicating tension failure of the bottom flange as well as slippage between flanges and the web due to horizontal shear, which also caused buckling deformations in the screws.

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Fabre, Agnès, Ivan Lillamand, Jean-Éric Masse, and Laurent Barrallier. "Neutron Evaluation of Stress in Industrial Screws." Materials Science Forum 490-491 (July 2005): 269–74. http://dx.doi.org/10.4028/www.scientific.net/msf.490-491.269.

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Neutron diffraction measurements were used in this study in order to determine the axial stress state in loaded screw from a specific assembly. The knowing of stress gradient is need to qualify a standard gauge used to calibrate the response of in-situ measurements using ultrasonic nondestructive technique. US is well adapted to perform measurements of the evolution of stress state on industrial screws during service life of the bolded assemblies.

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Xu, Fei, I. John Khan, Kenneth McGuinness, Avanish S. Parmar, Teresita Silva, N. Sanjeeva Murthy, and Vikas Nanda. "Self-Assembly of Left- and Right-Handed Molecular Screws." Journal of the American Chemical Society 135, no. 50 (December 3, 2013): 18762–65. http://dx.doi.org/10.1021/ja4106545.

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VCELAK, JOSEF, PETR TICHÝ, TOMÁŠ BOUDA, JIŘÍ CHOMIAK, and LADISLAV TÓTH. "PEDICLE SCREW CONVERGENCE IMPACT ON THE STABILITY OF TRANSPEDICULAR FIXATION SPINE MODEL IN CYCLIC LOADING: BIOMECHANICAL STUDY." Journal of Mechanics in Medicine and Biology 15, no. 05 (October 2015): 1550078. http://dx.doi.org/10.1142/s0219519415500785.

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The principle of this study is experimental measurement and description of behavior of transpedicular fixation during cyclic loading due to convergence of screw insertion. Investigations were made of three configurations of assemblies of posterior stabliization with converging screws at 0°, 20° and 40°. The experiment was inspired ASTM Standard F1717 and modified to minimize the effect of other parameters. The MTS 858.2 Mini Bionix testing system was used during the experiment, in conjunction with the Interface 1010ACK load cell. Data processing and analysis were carried out by Matlab R 20102b, MathWorks. The probed assemblies were cyclically loaded until structural failure occurred, always at the screwbone (or PUR block) interface, i.e., the "windshield wiper" effect. The measurement results show that while the rigidity of the assembly increases with increased convergence of transpedicular screws, they also indicate an increased initial rate of assembly damage accumulation, together with assembly failure during a reduced number of cyclic loading cycles. The mechanical behavioral study of transpedicular fixation is limited by the conditions of simplification of interpretation of complex movements and spinal pathophysiology in the attempt to minimize the effect of other parameters and exaggerated measurements.

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VIEIRA, FABIO ANTONIO, ANDRÉ SOUSA GARCIA, FERNANDO TADASHI SALVIONI UETA, DAVID DEL CURTO, RENATO HIROSHI SALVIONI UETA, and EDUARDO BARROS PUERTAS. "CORRELATION BETWEEN THE SCHANZ SCREW INSERTION ANGLE AND THE LOSS OF KYPHOSIS CORRECTION IN THORACOLUMBAR FRACTURES." Coluna/Columna 19, no. 3 (July 2020): 209–12. http://dx.doi.org/10.1590/s1808-185120201903179394.

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ABSTRACT Objective To compare the Schanz screw insertion angle and the loss of the regional kyphosis correction in thoracolumbar burst fractures following posterior short instrumentation surgery. Methods Patients with a thoracolumbar burst fracture between levels T11-L2 were divided into two groups (parallel and divergent) according to the angle formed between the Schanz screw and the vertebral plateau. Regional kyphosis was evaluated in preoperative, immediate postoperative and last follow-up radiographs. Results Of the 58 patients evaluated, 31 had a parallel assembly and 27 had a divergent assembly. When we analyzed the angle of kyphosis, no statistical difference was observed between the pre- and postoperative radiographs. However, a statistical difference in the last follow-up radiographs and in the final loss of the kyphosis correction was confirmed. Conclusion The insertion of Schanz screws with a divergent assembly presents better radiographic results with less loss of kyphosis correction angle when compared with the parallel assembly technique. Level of Evidence III; Retrospective cohort study.

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Zapłata, J. "Measurements of Temperature of CNC Machine Tool Ball Screw Utilising IR Method." International Journal of Applied Mechanics and Engineering 22, no. 3 (August 1, 2017): 769–77. http://dx.doi.org/10.1515/ijame-2017-0049.

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AbstractIn numerous papers it is proposed to use IR measurements of feed axis ball screw temperature distribution in order to compensate CNC machine tool thermal errors. The paper aims to validate reliability of the IR measurements in application to the feed axes ball screws. The identification of key factors influencing the accuracy of the IR measurements of ball screw temperature distribution has been conducted. A test-bench utilizing a ball screw assembly with built-in temperature sensors was introduced and the experimental data are presented along with conclusions.

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Lin, S. R., J. S. Yu, and C. S. Chang. "Stress analysis of screws in the fuel channel fastener assembly." International Journal of Pressure Vessels and Piping 117-118 (May 2014): 49–55. http://dx.doi.org/10.1016/j.ijpvp.2013.10.009.

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Sharke, Paul. "No Turn of the Screw." Mechanical Engineering 124, no. 12 (December 1, 2002): 42–45. http://dx.doi.org/10.1115/1.2002-dec-5.

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This article reviews about Torx fasteners that are not that easy to remove and needs better access for the removal. There had been no way to fit any other tool but a screwdriver through the hole by which he had originally tried to unscrew the fastener. Better access means that to remove the tilt wheel assembly, a job involving pressed pins and more special tools. Torx fasteners were originated in the late 1960s,when the Camcar division of Textron, developed their design to overcome some of the limitations of other screw styles. The Torx design resisted cam-out better than did Phillips screws. It also reduced the drive angle to 15° from the high 60° angle of hexagonal socket head screws or the still higher 90° angle of the square socket, or Robertson, screw. The new Textron design also relies on a vertical sidewall as a way of increasing a drive bit’s engagement.

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Li, Guoguang, Boqiang Shi, Ruiyue Liu, and Jie Gu. "Performance Analysis and Optimization of a 6-DOF Robotic Crusher." Journal of Robotics 2020 (November 4, 2020): 1–14. http://dx.doi.org/10.1155/2020/8812427.

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Considering the complexity of multidimension parameters and the mechanical performance of a 6-DOF robotic crusher, a multiobjective optimization function based on the transmission index and condition number is established. As an important operation in the screw theory, the reciprocal product between the transmission wrench screw of an actuator and the output twist screw of the mantle assembly is used to represent the instantaneous power. The expression of transmission index is derived according to the principle that constraint wrench screws apply no work to the mantle assembly. It can be used as a criterion to evaluate the transmission performance. Then, based on the Jacobian matrix, the equation of condition number is constructed which provides a criterion for evaluating kinematic accuracy. Finally, the workspace and singularity of the 6-DOF robotic crusher are analyzed to verify the rationality of the optimized variables. The results show that the optimized structure can completely crush the material in the workspace and effectively avoid singularity, which provides a basis for practical application.

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Studny, D., D. Rittel, and E. Zussman. "Impact Fracture of Screws for Disassembly." Journal of Manufacturing Science and Engineering 121, no. 1 (February 1, 1999): 118–26. http://dx.doi.org/10.1115/1.2830563.

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Environmental legislation urges manufacturers to develop effective technologies to cope with obsolete products. The goal is to optimize the disassembly procedure (cost, efficiency) with emphasis on potential recycling. In this work we adopt a destructive approach to product disassembly as an alternative to reverse assembly. Specifically we investigate unsupported screwed assemblies for which the screw head is protruding. Disassembly consist of breaking this head by applying side impact. The transient forces are measured by means of an instrumented bar. Experiments were conducted on various screw diameters and materials to assess the feasibility of this process. Typical design parameters (energy, time and forces) were measured. The fracture mechanism(s) was characterized by fractographic analysis. Results are presented and potential applications of this technique to efficient disassembly are discussed. The results are integrated into the preliminary design of robotic disassembler.

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Chumakov, Roman. "Optimal control of screwing speed in assembly with thread-forming screws." International Journal of Advanced Manufacturing Technology 36, no. 3-4 (November 22, 2006): 395–400. http://dx.doi.org/10.1007/s00170-006-0839-1.

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Althoefer, Kaspar, Bruno Lara, and Lakmal D. Seneviratne. "Monitoring of Self-Tapping Screw Fastenings Using Artificial Neural Networks." Journal of Manufacturing Science and Engineering 127, no. 1 (February 1, 2005): 236–43. http://dx.doi.org/10.1115/1.1831286.

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Screw fastenings account for a quarter of all assembly operations and automation of the process is highly desirable. This paper presents a novel strategy for monitoring this manufacturing process, focusing on the insertion of self-tapping screws. An artificial neural network (ANN), using “Torque-versus-Insertion-Depth” signature signals as input, is designed to distinguish between successful and failed insertions. The ANN is first tested using simulation data from an analytical model for screw insertions, and then validated using experimental torque signals obtained from an electric screwdriver. The results demonstrate that ANNs can effectively monitor the screw fastening process and cope with a wide range of insertion cases interpolating for unseen insertion signals.

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Toth-Tascau, Mirela, Flavia Bălănean, Mircea Krepelka, Lucian Rusu, and Cristian Toader-Pasti. "Computing Simulation of the Influence of Plate Design, Material, and Screw Positioning on Biomechanical Behavior of Ulna Bone Plates." Key Engineering Materials 583 (September 2013): 115–18. http://dx.doi.org/10.4028/www.scientific.net/kem.583.115.

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Throughout history, fractures have been treated by immobilization, traction, and internal fixation. Construction of a stabilization system composed of bone plate and screws combination depends on factors such as type of fracture, biomechanical behavior of stabilization system, and surgical preference. In this study, the influence of plate design, material properties, and screw placement was investigated through the use of Experimental Design and Finite Element simulation. A three dimensional model of the ulna bone was reconstructed from computer tomography images and a simple oblique fracture was simulated. The fracture was stabilized in different modes, using combinations of three different design plates with the material properties of stainless steel and titanium alloy fixed with three, four, and six screws. The biomechanical behavior was compared in terms of equivalent stress and total deformation. Results showed that the fixation mode and plate design have the largest influence on the biomechanical behavior of the bone-plate assembly.

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Matsukawa, Keitaro, Takashi Kato, Ralph Mobbs, Yoshiyuki Yato, and Takashi Asazuma. "Combination of sacral-alar-iliac screw and cortical bone trajectory screw techniques for lumbosacral fixation: technical note." Journal of Neurosurgery: Spine 33, no. 2 (August 2020): 186–91. http://dx.doi.org/10.3171/2020.1.spine191420.

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OBJECTIVELumbosacral fixation plays an important role in the management of devastating spinal pathologies, including osteoporosis, fracture, infection, tumor resection, and spinal deformities, which require long-segment fusion constructs to the sacrum. The sacral-alar-iliac (SAI) screw technique has been developed as a promising solution to facilitate both minimal invasiveness and strong fixation. The rationale for SAI screw insertion is a medialized entry point away from the ilium and in line with cranial screws. The divergent screw path of the cortical bone trajectory (CBT) provides a higher amount of cortical bone purchase and strong screw fixation and has the potential to harmoniously align with SAI screws due to its medial starting point. However, there has been no report on the combination of these two techniques. The objective of this study was to assess the feasibility of this combination technique.METHODSThe subjects consisted of 17 consecutive patients with a mean age of 74.2 ± 4.7 years who underwent posterior lumbosacral fixation for degenerative spinal pathologies using the combination of SAI and CBT fixation techniques. There were 8 patients with degenerative scoliosis, 7 with degenerative kyphosis, 1 with an osteoporotic vertebral fracture at L5, and 1 with vertebral metastasis at L5. Fusion zones included T10–sacrum in 13 patients, L2–sacrum in 2, and L4–sacrum in 2.RESULTSNo patients required complicated rod bending or the use of a connector for rod assembly in the lumbosacral region. Postoperative CT performed within a week after surgery showed that all lumbosacral screws were in correct positions and there was no incidence of neurovascular injuries. The lumbosacral bone fusion was confirmed in 81.8% of patients at 1-year follow-up based on fine-cut CT scanning. No patient showed a significant loss of spinal alignment or rod fracture in the lumbosacral transitional region.CONCLUSIONSThis is the first paper on the feasibility of a combination technique using SAI and CBT screws. This technique could be a valid option for lumbosacral fixation due to the ease of rod placement with potential reductions in operative time and blood loss.

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Koh, Seung Kee. "Stress Corrosion Cracking Life Estimation of Hold-Down Spring Screw for Nuclear Fuel Assembly." Key Engineering Materials 297-300 (November 2005): 1834–39. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.1834.

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Hold-down spring screw fractures due to primary water stress corrosion cracking were observed in nuclear fuel assemblies. The screw fastens hold-down springs that are required to maintain the nuclear fuel assembly in contact with upper core plate and permit thermal and irradiation-induced length changes. In order to investigate the primary causes of the screw fractures, the finite element stress analysis and fracture mechanics analysis were performed on the hold-down spring assembly. The elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded the yield strength of the screw material, resulting in local plastic deformation. Preloading on the screw applied for tightening had beneficial effects on the screw strength by reducing the stress level at the critical regions, compared to the screw without preload. Calculated deflections and strains at the hold-down springs using the finite element analysis were in very close agreements with the experimentally measured deflections and strains. Primary water stress corrosion cracking (PWSCC) life of the Inconel 600 screw was predicted by integrating the Scott’s model and resulted in a life of 1.42years, which was fairly close to the field experience. Cracks were expected to originate at the threaded region of the screw and propagated to the opposite side of the spring, which was confirmed by the fractographic analysis of the fractured screws.

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RAMAKRISHNA, K., I. SRIDHAR, S. SIVASHANKER, V. K. GANESH, and D. N. GHISTA. "ANALYSIS OF AN INTERNAL FIXATION OF A LONG BONE FRACTURE." Journal of Mechanics in Medicine and Biology 05, no. 01 (March 2005): 89–103. http://dx.doi.org/10.1142/s0219519405001333.

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A major concern when a fractured bone is fastened by stiff-plates to the bone on its tensile surface is excessive stress shielding of the bone. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays bone healing. Likewise, the tensile stress shielding of the healed bone underneath the plate also does not enable it to recover its tensile strength. Initially, the effect of a uniaxial load and a bending moment on the assembly of bone and plate is investigated analytically. The calculations showed that the screws near the fracture site transfers more load than the screws away from the fracture site in axial loading and it is found that less force is required when the screw is placed near to fracture site than the screw placed away from the fracture site to make the bone and plate bend with same radius of curvature when subjected to bending moment. Finally, the viability of using a stiffness graded bone-plate as a fixator is studied using finite element analysis (FEA): the stiffness-graded plate cause less stress-shielding than stainless steel plate.

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De Agostinis, M., S. Fini, and G. Olmi. "The influence of lubrication on the frictional characteristics of threaded joints for planetary gearboxes." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 15 (August 9, 2016): 2553–63. http://dx.doi.org/10.1177/0954406215605863.

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Planetary gearboxes generally consist of a ring gear, or gear body, connected with the input and output flanges by means of several screws, equally spaced along the diameter. The ring gear is manufactured with steel, whereas the flanges are usually made of cast iron. These screws must provide axial preload between the parts, allowing the assembly withstanding the breakaway torque given by the difference between the output and input torque applied to the gearbox. For a given screw geometry, the axial preload can be calculated, provided that the friction coefficients in the thread and in the underhead are known. Most often, the tightening torque is the only parameter being controlled during assembly and service operations. Hence, it is mandatory to know the friction coefficients of the joint. These depend, among others, on the hardness, roughness and texture of the mating surfaces, as well as on the lubrication state of the joint. In fact, the addition of a lubricant modifies the tribological behavior of the joint, thus the wearing evolution of the surfaces across repeated tightening operations. The present work tackles the following two aspects: (i) the characterization of the preloading force–tightening torque relationship on the actual component by means of a dedicated specimen, (ii) the evaluation of the influence of lubrication on the evolution of the frictional characteristics of the joint across several re-tightening operations. The present work has been carried out by means of both numerical finite element analyses and experimental stress analysis techniques.

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Baker, J. E. "Using the Single Reciprocal Screw to Confirm Mobility of a Six-Revolute Linkage." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 10 (April 22, 2010): 2247–55. http://dx.doi.org/10.1243/09544062jmes2062.

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Overconstrained kinematic chains have been discovered mostly by analytical or geometrical means or through a synthesizing procedure. In a few instances they have succumbed to computer-aided methods, and those solutions can, in effect, be reduced to a single one. This loop, of six revolutes, is described by parametric conditions that provide little information about its physical make-up. The existence of a lone screw reciprocal to the system defined by the loop's joint screws is the basis here for demonstrating analytically the linkage's mobility and determining its mode of assembly. In addition, it is shown that seven new linkages can be developed from this solution as isomeric variants.

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Alpatov, Vadim, and Alexey Soloviev. "Thin-walled profiles and their joint assembly units built with screws: numerical studies of load bearing capacity." MATEC Web of Conferences 196 (2018): 01008. http://dx.doi.org/10.1051/matecconf/201819601008.

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There is a tendency to reduce weight of load-bearing metal structures being developed and successfully realized in modern building construction. This idea serves as a basis for a whole scientific direction, named Development and application of light steel thin-walled structures (LSTS). Among them, LTST built with pop-rivets and thread-cutting screws are most widespread due to their simplicity and relative cheapness This paper presents numerical studies of LSTS joint assembly units built with screws and their load bearing capacity. The peculiarity of these units consists in misalignment of joint elements. The calculation was performed in the SolidWorks Simulation System. The modeled node is a three-dimensional assembly consisting of solid components. The results of the study are as follows: 1) thin-walled profiles have a significant sensitivity to eccentricity; 2) it is unacceptable to disregard eccentricities for thin-walled profiles and their joint connections; 3) eccentricities should be compensated by measures to improve reliability in joint connections design.

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Zhang, Weifang, Yuanxing Huang, Wei Dai, Xiaoshuai Jin, and Chang Yin. "A Fracture Analysis of Ti-10Mo-8V-1Fe-3.5Al Alloy Screws during Assembly." Materials 9, no. 10 (October 19, 2016): 852. http://dx.doi.org/10.3390/ma9100852.

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Saalfrank, Rolf W., Bernhard Demleitner, Sabine Kareth, Norbert Löw, and Stefan Trummer. "Towards New Materials Via Self-Assembly Cage Compounds, Coordination Polymers, Discs, and Screws." Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 356, no. 1 (February 1, 2001): 71–90. http://dx.doi.org/10.1080/10587250108023688.

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Purcar, Carmen, Mircea Bădescu, and Marinela Inţă. "Studies on wheel mounting options on shafts." MATEC Web of Conferences 290 (2019): 01016. http://dx.doi.org/10.1051/matecconf/201929001016.

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The paper presents a general description of chains and chain transmissions, their advantages and disadvantages. A triple chain wheel is then projected into the CATIA V5 program. A static analysis of some wheel mounting variants on a camshaft with the Generative Structural Analysis module in the CATIA V5 program is then made. The orientation-fastening variants with a wedge, two feathers or three screws positioned equidistant at 120 degrees on a diameter are analysed. As a result of the finite element analysis, the conclusion is that the three-screw variant is the most appropriate. Material stresses and deformations are smaller, simpler processability, fewer types of components are present overall, maintenance is simpler, and the excentricity of the assembly is lower, with lower vibrations in operation.

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Chumakov, Roman. "An artificial neural network for fault detection in the assembly of thread-forming screws." Journal of Intelligent Manufacturing 19, no. 3 (April 13, 2008): 327–33. http://dx.doi.org/10.1007/s10845-008-0085-5.

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Magonski, Zbigniew, Barbara Dziurdzia, Henryk Jankowski, Jan Koprowski, Teresa Kenig, Dorota Szwagierczak, and Jan Kulawik. "Stack of Planar Double-Sided Solid Oxide Fuel Cells." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000281–87. http://dx.doi.org/10.4071/cicmt-2012-wa13.

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A new design of a small power SOFC battery is presented. The battery consists of an array of flat double-sided fuel cells assembled with only two screws. Fuel cells are made with the application of commercially available HTCC green tapes. Eight layers of 180μm thick anode tape (YSZ+NiO) constitute the anode base structure of the double-sided fuel cell. Within the anode base structure, the separate areas serve as: the functional anode, the anode current collector, and the support for the anode functional layer. Also a network of fine micro channels is embedded within the anode base structure. The individual double-sided fuel cell is completed by deposition of the following layers, which constitute the electrolyte, the cathode, and the cathode current collector These layers are deposited on both sides of the anode base structure by means of screen-printing. Each double-sided fuel cell is provided with the own separate fuel distributor and combustion product collector. That beneficial feature enables completing the tests, separately for each cell, prior assembly into battery.

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Sherrill, John T., David B. Bumpass, and Erin M. Mannen. "22370 Mechanical Analysis of Posterior Spinal Fusion Assemblies Intended to Cross the Cervicothoracic Junction." Journal of Clinical and Translational Science 5, s1 (March 2021): 65–66. http://dx.doi.org/10.1017/cts.2021.571.

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ABSTRACT IMPACT: A comparative evaluation of the mechanical properties of commonly used posterior spinal fusion assemblies will allow surgeons to choose an assembly based on desired properties. The results will better inform surgical decision making and may lead to improved patient outcomes. OBJECTIVES/GOALS: The objective of this study is to evaluate and compare the mechanical properties of three posterior spinal fusion assemblies commonly used to cross the cervicothoracic junction. Fusion success depends on immobilization of vertebrae. The results will better inform surgical decision making and may improve patient outcomes. METHODS/STUDY POPULATION: Three titanium alloy posterior spinal fusion assemblies intended to cross the cervicothoracic junction underwent static compressive bending, tensile bending, and torsion as described in ASTM F1717 to a torque of 2.5 Nm: 3.5mm rods (Assembly A), 3.5mm to 5.5mm dilating rods (Assembly B), and two 3.5mm rods connected to two 5.5mm rods (Assembly C). Five samples of each assembly were attached to ultrahigh molecular weight polyethylene blocks via multiaxial screws for testing. The distance from the axis of rotation to the point of attachment of the rod and cervical screw was used as the lever arm to calculate the force required to create the desired torque for each test: lever arm of 37mm, requiring 67.6N of force to generate 2.5Nm of torque. Force and displacement were recorded, and stiffness of each construct calculated. RESULTS/ANTICIPATED RESULTS: An ANOVA was performed and resulted in p-values all p<0.005, indicating the test groups were significantly different. Therefore, pairwise t-tests with Bonferroni corrections (p<0.017) were used to determine pairs that were significantly different. Assembly A (3.5mm rods only) was found to be significantly less stiff than Assembly B (dilating rods) and Assembly C (3.5mm-connector-5.5mm rods) in each mode of bending: compression bending, tension bending, and torsion. Assembly A had a significantly greater range of motion in compression bending and torsion, but not tension bending, when compared to Assembly B and Assembly C. The only significant difference between Assembly B and Assembly C was found in the stiffness value of compression bending. DISCUSSION/SIGNIFICANCE OF FINDINGS: The results of this study indicate that incorporating a 5.5mm rod in a fusion assembly adds significant stiffness to the posterior spinal fusion construct. When stability of a fusion is of heightened concern, as demonstrated by the ASTM F1717 vertebectomy (worst case scenario) model, including 5.5mm rods increases the likelihood of fusion success.

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Saalfrank, Rolf W., Bernhard Demleitner, Sabine Kareth, Norbert Low, and Stefan Trummer. "ChemInform Abstract: Towards New Materials via Self-Assembly Cage Compounds, Coordination Polymers, Discs, and Screws." ChemInform 32, no. 38 (May 24, 2010): no. http://dx.doi.org/10.1002/chin.200138276.

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Li, Xin, Geng Liu, Chunyu Song, Xiaojun Fu, Shangjun Ma, and Qi Wan. "Rigid-Body Dynamic Analysis of Multi-Stage Planetary Roller Screw Mechanism." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 5 (October 2020): 1001–9. http://dx.doi.org/10.1051/jnwpu/20203851001.

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Based on the structural characteristics of the multi-stage Planetary Roller Screw Mechanism (PRSM), the motion and force among the different stages are analyzed. In terms of the Newton's second law, the rigid-body motion equations of the multi-stage PRSM without considering the manufacturing and assembly errors are derived. Then, the method for solving the motion equations is given. The forces acting on the parts in the multi-stage PRSM and the motion of the mechanism can be obtained from the present rigid-body dynamic model. The influence of the friction coefficients among the different stages on the dynamic characteristics of the multi-stage PRSM is discussed. The results show that the forces acting on the first-stage PRSM are larger than that acting on the second-stage PRSM, although the nominal radius of the screw in the first-stage PRSM is smaller. The friction coefficient between the nut and the screw in the different stages has the great influence on the efficiency of multi-stages PRSM with small helix angles, while that among the screws in the different stages has the slight effect on the efficiency.

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Kowal, Michał. "Sensorless compensation system for thermal deformations of ball screws in machine tools drives." Archives of Mechanical Technology and Materials 36, no. 1 (December 1, 2016): 1–6. http://dx.doi.org/10.1515/amtm-2016-0001.

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Abstract The article presents constructional, technological and operational issues associated with the compensation of thermal deformations of ball screw drives. Further, it demonstrates the analysis of a new sensorless compensation method relying on coordinated computation of data fed directly from the drive and the control system in combination with the information pertaining to the operational history of the servo drive, retrieved with the use of an artificial neural networks (ANN)-based learning system. Preliminary ANN-based models, developed to simulate energy dissipation resulting from the friction in the screw-cap assembly and convection of heat are expounded upon, as are the processes of data selection and ANN learning. In conclusion, the article presents the results of simulation studies and preliminary experimental evidence confirming the applicability of the proposed method, efficiently compensating for the thermal elongation of the ball screw in machine tool drives.

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Židek, Kamil, Peter Lazorík, Ján Piteľ, and Alexander Hošovský. "An Automated Training of Deep Learning Networks by 3D Virtual Models for Object Recognition." Symmetry 11, no. 4 (April 5, 2019): 496. http://dx.doi.org/10.3390/sym11040496.

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Small series production with a high level of variability is not suitable for full automation. So, a manual assembly process must be used, which can be improved by cooperative robots and assisted by augmented reality devices. The assisted assembly process needs reliable object recognition implementation. Currently used technologies with markers do not work reliably with objects without distinctive texture, for example, screws, nuts, and washers (single colored parts). The methodology presented in the paper introduces a new approach to object detection using deep learning networks trained remotely by 3D virtual models. Remote web application generates training input datasets from virtual 3D models. This new approach was evaluated by two different neural network models (Faster RCNN Inception v2 with SSD, MobileNet V2 with SSD). The main advantage of this approach is the very fast preparation of the 2D sample training dataset from virtual 3D models. The whole process can run in Cloud. The experiments were conducted with standard parts (nuts, screws, washers) and the recognition precision achieved was comparable with training by real samples. The learned models were tested by two different embedded devices with an Android operating system: Virtual Reality (VR) glasses, Cardboard (Samsung S7), and Augmented Reality (AR) smart glasses (Epson Moverio M350). The recognition processing delays of the learned models running in embedded devices based on an ARM processor and standard x86 processing unit were also tested for performance comparison.

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Otsuki, Bungo, Mitsuru Takemoto, Shunsuke Fujibayashi, Hiroaki Kimura, Kazutaka Masamoto, and Shuichi Matsuda. "Utility of a custom screw insertion guide and a full-scale, color-coded 3D plaster model for guiding safe surgical exposure and screw insertion during spine revision surgery." Journal of Neurosurgery: Spine 25, no. 1 (July 2016): 94–102. http://dx.doi.org/10.3171/2015.12.spine15678.

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Several articles have described the use of screw insertion guides during primary spine surgery; however, the use of such a guide during revision surgeries has not been described. The purpose of this study is to describe the utility of a custom screw insertion (CSI) guide assembled using a novel method and a full-scale, color-coded 3D plaster (FCTP) model for safe and accurate revision surgery. The authors applied the CSI guide and the FCTP model in 3 cases. In the first case, a patient with multiple failed cervical spine surgeries underwent occipitocervicothoracic fusion. After a successful result for this patient, the authors applied the CSI guide in 2 other patients who underwent revision lumbar fusion surgeries to confirm the accuracy and the efficacy of the CSI guides in such cases. The models and guides were fabricated using rapid prototyping technology. The effectiveness of these methods was examined. The FCTP model was designed using CT data. During model assembly, implants inserted during previous surgery were removed virtually, and for the cervical spine, vertebral arteries were colored red for planning. The CSI guide was designed with 5 or 6 arms to fit the bone surface precisely after removing artifacts. Surgery was performed by referring to the FCTP model. Because the actual structure of the bone surface was almost identical to that of the FCTP model, surgical exposure around the complex bone shape proceeded smoothly. The CSI guides were positioned accurately to aid the successful insertion of a pedicle screw into the C-2 vertebra in the case of cervical revision surgery, and 4 pedicle screws for lumbar vertebrae in the 2 other patients. Postoperative CT scans showed that all screw positions closely matched those predicted during the preoperative planning. In conclusion, the FCTP models and the novel CSI guides were effective for safe and accurate revision surgery of the spine.

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Armentia, Mikel, Mikel Abasolo, Ibai Coria, and Abdel-Hakim Bouzid. "On the Use of a Simplified Slip Limit Equation to Predict Screw Self-Loosening of Dental Implants Subjected to External Cycling Loading." Applied Sciences 10, no. 19 (September 26, 2020): 6748. http://dx.doi.org/10.3390/app10196748.

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Self-loosening of the prosthetic screws is a major mechanical problem affecting roughly 10% of dental implants, according to the literature. This phenomenon may lead to micro-movements that produce crestal bone loss, peri-implantitis, or structural failure of the implant assembly. In this paper, a simple and effective tool to predict self-loosening under masticatory loads is presented. The loads acting on the screw are obtained from a simple finite element (FE) model, and introduced in a mathematical formula that calculates the torque needed to loosen the screw; self-loosening will occur when this torque becomes zero. In this sense, all the parameters involved in self-loosening phenomenon can be easily identified, and their effect quantified. For validating purposes, 90 experimental tests were performed in a direct stress test bench. As a result, a powerful tool with a maximum experimental error of 7.6% is presented, allowing dental implant manufacturers to predict eventual occurrence of self-loosening in their developed dental implant products and take corrective actions at preliminary design stage. Furthermore, the following clinical implications can be directly derived from the methodology: a higher screw preload, that is a higher tightening torque, improves self-loosening response of the dental implant and, similarly, for a given preload force, higher friction coefficient and screw metric, as well as lower pitch and thread angle values, are also found to be beneficial.

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Laksanasittiphan, Somchai, Karuna Tuchinda, Anchalee Manonukul, and Surasak Suranuntchai. "Use of Deep Cryogenic Treatment to Reduce Particle Contamination Induced Problem in Hard Disk Drive." Key Engineering Materials 730 (February 2017): 265–71. http://dx.doi.org/10.4028/www.scientific.net/kem.730.265.

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In this study, the effect of deep cryogenic treatment on the generation of stainless steel particles in screw tightening process in hard disc drive assembly was investigated. During the cryogenic treatment, the specimens of both stainless steel screw and contacting tool (called as “bit”) material were quenched in a chamber containing liquid nitrogen at-196 oC with the soaking times of 33 hr. The specimens were then subjected to sliding wear tests under normal loading conditions. The experiments used for simulating dry sliding wear mechanisms were carried out by TriboGear machine. The machine consists of a stationary bit loaded against the plate containing screw. The screws used were made of martensitic 410 stainless steel and the bit was made of S2 tool steel. The experiments were carried out under both under single and multiple loading cycles under the normal load corresponding to the effective stresses higher and lower than the yield strength of screw material. The results showed that the deep cryogenic treatment led to more homogeneous distribution of fine size carbide particles in both martensitic 410 stainless steel and S2 tool steel. This lead to different failure mechanism of the stainless steel resulting in smaller and slender stainless steel particles generated. This was expected due to the effect of the change in the dimension of carbide, the stress distribution in the material and the crack propagation path.

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Desrochers, Alain, Walid Ghie, and Luc Laperrie`re. "Application of a Unified Jacobian—Torsor Model for Tolerance Analysis." Journal of Computing and Information Science in Engineering 3, no. 1 (March 1, 2003): 2–14. http://dx.doi.org/10.1115/1.1573235.

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Because of uncertainties in manufacturing processes, a mechanical part always shows variations in its geometrical characteristics (ex. form, dimension, orientation and position). Quality then often reflect how well tolerances and hence, functional requirements, are being achieved by the manufacturing processes in the final product. From a design perspective, efficient methods must be made available to compute, from the tolerances on individual parts, the value of the functional requirement on the final assembly. This is known as tolerance analysis. To that end, existing methods, often based on modeling of the open kinematic chains in robotics, are classified as deterministic or statistical. These methods suppose that the assembled parts are not perfect with regard to the nominal geometry and are rigid. The rigidity of the parts implies that the places of contacts are regarded as points. The validation or the determination of a tolerance zone is therefore accomplished by a series of simulation in specific points subjected to assembly constraints. To overcome the limitations and difficulties of point based approaches, the paper proposes the unification of two existing models: the Jacobian’s matrix model, based on the infinitesimal modeling of open kinematic chains in robotics, and the tolerance zone representation model, using small displacement screws and constraints to establish the extreme limits between which points and surfaces can vary. The approach also uses interval algebra as a novel method to take tolerance boundaries into account in tolerance analysis. The approach has been illustrated on a simple two parts assembly, nevertheless demonstrating the capability of the method to handle three-dimensional geometry. The results are then validated geometrically, showing the overall soundness of the approach.

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Fox, Steven R., and Reinhold M. Schuster. "Strength of wind load bearing wall stud-to-track connections." Canadian Journal of Civil Engineering 29, no. 5 (October 1, 2002): 777–86. http://dx.doi.org/10.1139/l02-074.

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Cold-formed steel structural members are often used in building construction, with a common application being wind load bearing steel studs. The studs frame into horizontal steel track members at the top and bottom of the wall assembly, with the stud-to-track connection typically being made with self-drilling screws or welds. The design of the wall stud must include a check of the web crippling capacity at the end reactions. The type of end bearing that exists in these stud-to-track connections is not explicitly addressed by the current North American cold-formed steel design documents. Reported in this paper are the results and analysis of a collection of end-one-flange web crippling tests of common stud-to-track connections. The tests show that there are two failure modes: web crippling of the stud, and punch-through of the track flange. Design expressions are proposed to predict the capacity of the connection based on these two modes of failure. The effects of increasing the gap between the stud and the track and the effects of missing screws in the stud-to-track connection are also discussed.Key words: cold-formed steel, steel studs, structural design, connections, web crippling.

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Cunningham, Bryan W., Paul D. Sponseller, Ashley A. Murgatroyd, Jun Kikkawa, and P. Justin Tortolani. "A comprehensive biomechanical analysis of sacral alar iliac fixation: an in vitro human cadaveric model." Journal of Neurosurgery: Spine 30, no. 3 (March 2019): 367–75. http://dx.doi.org/10.3171/2018.8.spine18328.

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OBJECTIVEThe objective of the current study was to quantify and compare the multidirectional flexibility properties of sacral alar iliac fixation with conventional methods of sacral and sacroiliac fixation by using nondestructive and destructive investigative methods.METHODSTwenty-one cadaveric lumbopelvic spines were randomized into 3 groups based on reconstruction conditions: 1) S1–2 sacral screws; 2) sacral alar iliac screws; and 3) S1–iliac screws tested under unilateral and bilateral fixation. Nondestructive multidirectional flexibility testing was performed using a 6-degree-of-freedom spine simulator with moments of ± 12.5 Nm. Flexion-extension fatigue loading was then performed for 10,000 cycles, and the multidirectional flexibility analysis was repeated. Final destructive testing included an anterior flexural load to construct failure. Quantification of the lumbosacral and sacroiliac joint range of motion was normalized to the intact spine (100%), and flexural failure loads were reported in Newton-meters.RESULTSNormalized value comparisons between the intact spine and the 3 reconstruction groups demonstrated significant reductions in segmental flexion-extension, lateral bending, and axial rotation motion at L4–5 and L5–S1 (p < 0.05). The S1–2 sacral reconstruction group demonstrated significantly greater flexion-extension motion at the sacroiliac junction than the intact and comparative reconstruction groups (p < 0.05), whereas the sacral alar iliac group demonstrated significantly less motion at the sacroiliac joint in axial rotation (p < 0.05). Absolute value comparisons demonstrated similar findings. Under destructive anterior flexural loading, the S1–2 sacral group failed at 105 ± 23 Nm, and the sacral alar iliac and S1–iliac groups failed at 119 ± 39 Nm and 120 ± 28 Nm, respectively (p > 0.05).CONCLUSIONSAlong with difficult anatomy and weak bone, the large lumbosacral loads with cantilever pullout forces in this region are primary reasons for construct failure. All reconstructions significantly reduced flexibility at the L5–S1 junctions, as expected. Conventional S1–2 sacral fixation significantly increased sacroiliac motion under all loading modalities and demonstrated significantly higher flexion-extension motion than all other groups, and sacral alar iliac fixation reduced motion in axial rotation at the sacroiliac joint. Based on comprehensive multidirectional flexibility testing, the sacral alar iliac fixation technique reduced segmental motion under some loading modalities compared to S1–iliac screws and offers potential advantages of lower instrumentation profile and ease of assembly compared to conventional sacroiliac instrumentation techniques.

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Cerrolaza, M., W. Carrero, J. Cedeño, and L. Valencia. "FINITE ELEMENT ANALYSIS OF A DEVICE FOR ALVEOLAR OSTEOGENIC DISTRACTION IN HUMAN MANDIBLE." Biomedical Engineering: Applications, Basis and Communications 27, no. 04 (August 2015): 1550034. http://dx.doi.org/10.4015/s1016237215500349.

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Distractor devices are implanted temporarily in the bony structure in order to regenerate the bone tissue required and then be removed from the distraction site at the end of the consolidation period of callus. In this research, an osteogenic alveolar distractor (OAD) to deal with jaw bone deficiency in the alveolar area is proposed and described in this study. It addresses the FEM analysis of the proposed model of an OAD under physiological loading after the implantation. A finite element model subjected to physiological load exerted by the voluntary protrusion of the tongue on the alveolar distractor was analyzed and developed. The applied biological loads were the forces generated by the involuntary movement of the tongue against the distal end of the assembly. Both of them act on the head of the distractor screw, in the same direction but in opposite directions. The distraction device has been simulated on the alveolar bone, taking into account the most critical conditions that may occur during the distraction osteogenesis. The alveolar distractor proposed has a geometry that allows, by using only two intra-cortical screws, the attachment of the base plate to the alveolar bone without sacrificing a large periosteum area of the periosteum, which is primarily responsible for blood supply and nutrient source to the bone segment being distracted. The resulting stresses were lower than those corresponding to the resistance threshold in the bone.

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Armentia, Mikel, Mikel Abasolo, Ibai Coria, and Joseba Albizuri. "Fatigue Design of Dental Implant Assemblies: A Nominal Stress Approach." Metals 10, no. 6 (June 3, 2020): 744. http://dx.doi.org/10.3390/met10060744.

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Fatigue is the most common mechanical failure type in dental implants. ISO 14801 standardizes fatigue testing of dental implants, providing the load-life curve which is most useful for comparing the fatigue behavior of different dental implant designs. Based on it, many works were published in the dental implant literature, comparing different materials, component geometries, connection types, surface treatments, etc. These works are useful for clinicians in order to identify the best options available in the market. The present work is intended not for clinicians but for dental implant manufacturers, developing a design tool that combines Finite Element Analysis, fatigue formulation and ISO 14801 experimental tests. For that purpose, 46 experimental tests were performed on BTI INTERNA® IIPSCA4513 implants joined with INPPTU44 abutments by means of INTTUH prosthetic screws under three different tightening torque magnitudes. Then, the load case was reproduced in a FE model from where the nominal stress state in the fatigue critical section was worked out. Finally, Walker criterion was used to represent accurately the effects of mean stress and predict fatigue life of the studied dental implant assembly, which can be extended to most of the products of BTI manufacturer. By means of this tool, dental implant manufacturers will be able to identify the critical design and assembly parameters in terms of fatigue behavior, evaluate their influence in preliminary design stages and consequently design dental implants with significantly better fatigue response which in turn will reduce future clinical incidences.

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Salah A. Youssef, Rami Mohammed Galal, Ghada E. Hamza, Ghith Fayez Saeed Aldhahri, Ahmad Ramzi Abdu Alzaylaei, Mohammed Saleh Mohammed Alamoudi, Abdullah Abdulrahman Ahmad Benjabi, et al. "Finite Element Analysis on All on Four Implant Screw Retained Mandibular Fixed Prosthesis. (Material Selection Role)." International Journal of Innovative Research in Medical Science 5, no. 12 (December 28, 2020): 650–55. http://dx.doi.org/10.23958/ijirms/vol05-i12/1027.

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Aim: to indicate the importance of adequate selection of all on four-fixed implant supported hybrid mandibular prosthesis material to reduce bone stresses. Materials and methods: one three-dimensional simplified geometric model, for bone and fixed prosthesis, was created by using engineering CAD/CAM software. On the other hand, implant system manufacturer data gave sufficient geometrical data to model it exactly. The modelled part was transferred to ANSYS for assembly, meshing, and analysis. Three overlying materials were tested; Acrylic, Polycarbonate, and Zirconia above the cobalt chromium bar. The lowest area of the cortical bone was set to be fixed in place as boundary condition. While unilaterally load of 250N was applied vertically on central fossa of first and second molars as two loading cases. Results: changing overlying material resulted in, cortical bone and implant complex receiving Von Mises stress in sequence with material rigidity. The more rigid the overlying material the less bone stresses with first molar loading, while, opposite trend (sequence) appeared with second molar loading. On the other hand, bar, coping, screws, mucosa, and spongy bone deformations and stresses decreased with increasing overlying material rigidity. Where, all the model components showed stresses and deformations within the physiological limits. Conclusions: More rigid overlying material is recommended to reduce stresses on bar, coping, screws, mucosa, and spongy bone. Overlying material selection for cortical bone and implant complex is extremely tricky. That it showed same behaviour as other soft tissues with applying load close to the bar (short cantilever arm), then inverted behaviour with shifting the applied load away from first to second molar (increasing cantilever arm).

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Vasilescu, Marius, Iulian Antoniac, Dan Ioan Stoia, Dan Laptoiu, Andreea Stoia, Cosmina Vigaru, and Sebastian Gradinaru. "Using Stainless Steel and Titanium Alloy in Charcot Foot Reconstruction. FEA Simulation and Clinical Case." Revista de Chimie 71, no. 4 (May 5, 2020): 235–47. http://dx.doi.org/10.37358/rc.20.4.8062.

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The aim of the study was to simulate a clinical case of Charcot foot reconstruction, using finite element analysis (FEA). Our work starts from a clinical failure case of Charcot arthrodesis, were one stainless steel Midfoot Fusion Bolt (MBF) prematurely failed. Starting from CT images a 3D model of the foot was reconstructed and together with the intramedullary bolts a virtual assembly was build. In addition, a second 3D model containing 3 MBF screws and one titanium locking compression plate (LCP) was constructed. The loading conditions used in FEA were extracted based on foot biomechanics according to the gait phases. The results are showing the critical sections of the bolts and also the stress shielding effect that appears on the bolts when the plate is used as supplementary fixation element. By comparing the stress values on bolts and plate with the yield strength of stainless steel and titanium alloy that are regularly used for manufacturing these implants, a valid reconstruction solution was found. This result can help surgeons in establishing the proper bolt insertion and plate positioning for minimizing the implant failure risk.

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Cucos, Marius Marian, Ionut Madalin Pista, and Marius Ionut Ripanu. "Product engineering design enhancing by parameterizing the 3D solid model." MATEC Web of Conferences 178 (2018): 05011. http://dx.doi.org/10.1051/matecconf/201817805011.

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The research approach and the case study presented in the paper are oriented towards the convergent use of a parametric modelling algorithm and of an advanced integrated CAD/CAE solution for the optimization of the product engineering design, for reducing the product life cycle environmental impact and for providing sustainability in product development. First of all, a conceptual model for the research framework is proposed, where the use of mathematical models (equations/mathematical relations, etc.) integrated into advanced CAD/CAE design solutions leads to parameterizing of the product structure and obtaining of some product component families (gears, shafts, screws, nuts, bushings, etc.). The presented case study refers to the application of the above outlined solutions for enhancing the design effectiveness and efficiency of 3D product assembly and part models (hereby exemplified for component parts like shafts and gears) for a particular construction of a technological device, using the powerful tools of the integrated product family Creo Parametric (Pro/Engineer) as mechanical design software. Some suitable conclusions are finally presented and some directions of further researches are also included.

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Suhariyanto, Tatbita, Dzuraidah Wahab, and Mohd Rahman. "Product Design Evaluation Using Life Cycle Assessment and Design for Assembly: A Case Study of a Water Leakage Alarm." Sustainability 10, no. 8 (August 9, 2018): 2821. http://dx.doi.org/10.3390/su10082821.

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This study proposed the use of an LCA supported by a design efficiency evaluation based on Design for Assembly principles to reduce the environmental impact of a product. To illustrate the methodology, a water leakage alarm (WLA) was selected as the object for a case study. Based on the identification and evaluation of the LCA results, it was inferred that the stage with the highest environmental impact was the manufacturing stage (75.35%), followed by the use stage (23.88%), the disposal of the WLA (0.64%), and finally, the disposal of the batteries (0.14%). For the manufacturing stage, the most interrelated categories were the hazardous waste and human toxicity, while the use stage was the main contributor to ozone depletion and acidification. Moreover, the disposal of the WLA and batteries contributed to the bulk waste. Furthermore, from the assembly evaluation, the design efficiency of the product was 14%. Two recommendations for improving the design of the WLA were: (1) to reduce the number of screws from three units to one unit, and (2) to eliminate the use of a cable and to replace it with a wireless component. By implementing both the proposed recommendations, the design efficiency was improved by as much as 34%. From the environmental perspective, there is not much difference between the wired alarm and wireless alarm. The wired alarm was considered to be more environmentally friendly in terms of product manufacturing but the wireless alarm has an advantage in terms of design and energy efficiency. By combining LCA and DFA design evaluation, a more comprehensive perspective of the product life cycle can be achieved.

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Otoni, C. C., O. C. M. Pereira-Júnior, A. L. L. Blum, L. C. Vulcano, and C. Rahal. "Synthesis Pengo System plates for the treatment of long-bone diaphyseal fractures in dogs." Veterinary and Comparative Orthopaedics and Traumatology 21, no. 01 (2008): 59–63. http://dx.doi.org/10.3415/vcot-07-05-0049.

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SummaryA Brazilian orthopaedic company designed a stainless steel plate called Synthesis Pengo System (S.P.S.), which has one fixed and one changeable extremity. According to the assembly of the changeable extremity, it is possible to obtain dynamization or neutralization of the fracture site. Since the S.P.S. plate was developed for use in human patients, the aim of this study was to evaluate this system in long-bone diaphyseal fractures in dogs. Eight dogs with closed diaphyseal fractures of the femur (n= 1), radius and ulna (n=5), and tibia (n=2) were used. Patients were aged seven months to three years and weighed 18 to 31.2 kg. The S.P.S. plate was assembled with one fixed extremity and one changeable extremity in dynamization mode. The trail bar was positioned for synthesis modules with holes for cortical screws. The modules were positioned close to one another in two fractures and far away from the fracture site in the others. The bone healing occurred by external callus. Since motion at the fracture site determines the amount of callus required, the secondary bone healing that was observed in all of the cases indicated less rigid fixation of this system. A potential benefit of this system was a lesser interface contact with the bone since it was only done by trail bar. The major disadvantage was the prominence of the implant. It was possible to conclude that the S.P.S. plate appears to be a suitable method for the treatment of diaphyseal fractures in dogs.

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Pyatikrestovsky, Konstantin P., Vladimir I. Travush, Alexander A. Pogoreltsev, and Alexander A. Klyukin. "DEVELOPMENT OF STRUCTURES FROM SOLID WOOD FOR OBJECTS OF INFRASTRUCTURE." International Journal for Computational Civil and Structural Engineering 14, no. 1 (March 30, 2018): 145–54. http://dx.doi.org/10.22337/2587-9618-2018-14-1-145-154.

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New prefabricated lightweight structures made of solid wood with connections for joining and building metal screws for wood are proposed. Manufacture and assembly of basic elements-bars with a cross-section of 15x15 cm can be carried out in line conditions on the simplest woodworking equipment. The use of local tim-ber material has a number of advantages (ecological, economic and operational). The description of structures with manufacturing process, examples of buildings with vaulted and hipped roofing, connection arrangement, preparation of experimental samples with the use of new equipment of the National Research Moscow State University of Civil Engineering are given. The method of analysis with allowance for plastic deformations is under consideration. It provides additional economic advantages. The analysis is carried out by the method of integral estimates developed by Prof. V.M. Bondarenko for reinforced concrete structures and adapted to wooden structures by Prof. K.P. Pyatikrestovsky. Special strength criteria are used for the analysis of decks working together with the ribs (in a combined stressed state). It is planned to build buildings for various purposes in the ar-eas of development of the Far North of Russia.

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Casanova Garcia, Fernando, Andres Carrera Pinzon, Arlex Leyton, Andres Machado Caicedo, and Jose Jaime GarcIa Alvarez. "Development of an easy-to-assemble external fixation system for bone transport." DYNA 86, no. 208 (January 1, 2019): 53–59. http://dx.doi.org/10.15446/dyna.v86n208.68012.

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We developed a monolateral external fixation system for bone elongation easier to assemble than commercial systems since the clamps can be laterally assembled to the rail in contrast to the commercial systems where the clamps can only be assembled from the ends. The system is formed by clamps, screws, and a rail. The rail is composed of two carbon fiber circular rods of ½” diameter and 42-cm length. The clamps can slide with respect to the rail to allow bone distraction or may be fixed to the rail by using a wedge and a screw. The prototype was mechanically evaluated under the ASTM F1541 standard. The stiffness in axial, Medio Lateral bending (ML), Antero Posterior bending (AP), and flexo-torsional load were 117 N/mm, 46 N/mm, 8.7 N/mm, and 5.8 N-mm/°, respectively, which are on the range of stiffness of commercial systems.

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Jiang, Jing, Guang Chao Liu, Chao Feng Li, Lei Wang, Shu Ying Liu, and Bang Chun Wen. "Application of Visualized Design Method on the Designing of Articulatory Vibrating Screen." Applied Mechanics and Materials 121-126 (October 2011): 4396–404. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.4396.

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Articulatory vibrating screen is composed of multi-section screen with articulatory vibrating. The principle of even-thickness screening is referenced on its layout, with linear vibrating screen as the discharge end, with round vibrating screens as the feeding end, and also the intermediate screen. In accordance with the structural features of articulatory vibrating screen and under the condition of assembly module in Pro/E, mechanical components of articulatory vibrating screen are assembled in the light of the arrangement, the sequence, the restrictions and the modifications of installation. With the visualized research on the operational process, the three-dimensional illustrations of assembly model are established to ensure the correct design on every mechanical component of articulatory vibrating screen. The finite element model of vibrating screen is set up by its analysis software to carry out the analysis of finite element calculation and modal according to two operating modes of the regular work and the machine halt beyond resonance region. The analysis result indicates that the intensity and the rigidity of the vibrating screen are safe; the machine operation is stable; and no resonance phenomenon would happen. This study provides the theoretical reference for the design of similar machinery. It is of practical importance and economic value to apply the visualized design method into the design of articulatory vibrating screen.

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Dong, Peng, Shengdun Zhao, Yongqiang Zhao, Peng Zhang, and Yongfei Wang. "Design and experimental analysis of end face profile of tri-screw pump." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 4 (August 20, 2019): 481–89. http://dx.doi.org/10.1177/0957650919870373.

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This study proposes a new type of tri-screw pump, which has a 1:2:3 ratio of the active diameter of the screw, the diameter of the pitch circle, and the top diameter of the active screw. Fixed width correction method of the driven screw is also proposed to avoid wear of tooth top. The mathematical model of active and driven screws is established. To avoid the wear of the tooth top arc, several transition patterns are proposed, and the transition curve in the form of a circular arc is deduced. The designed screw curve is grinded, and the tri-screw pump is assembled. The hydraulic pump test bench is tested using the overflow valve to perform pressure loading of 3–5 MPa on the outlet of the screw pump. The outlet flow rate and pressure are tested, and results indicate that the output flow of the pump conforms to the designed flow rate. This study establishes the detailed equation of the end face profile of the tri-screw pump (active and driven screws) and corrects the arc profile of the line angle.

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Kromoser, Benjamin, and Thomas Pachner. "Optiknot 3D—Free-Formed Frameworks out of Wood with Mass Customized Knots Produced by FFF Additive Manufactured Polymers: Experimental Investigations, Design Approach and Construction of a Prototype." Polymers 12, no. 4 (April 21, 2020): 965. http://dx.doi.org/10.3390/polym12040965.

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Free-formed frameworks are architecturally appealing constructions. They allow for maximum creative freedom as well as for a structural optimization of the support structure. The design and construction of these kind of structures is complex however, and therefore challenging, with each frame member having an individual length, each cladding plate an individual dimension and especially each knot having an individual geometry. The result is that geometry optimization and production technology become the most important processes when striving for an economic and ecological construction. The goals of the authors are the automation of the design process by applying a parametric model and the collection of the complete complexity in the knots as well as the production of these knots without material wastage by additive manufacturing. The development process was split into three different phases: (1) Preliminary experiments determining the tension, compression and bending load-bearing behavior of the knots produced by additive manufacturing, using different polymer-based materials: ABS, ASA, PA-CF, PA6CT, PCX, PETG and a mixture of PLA and ABS. (2) Development of an automated digital workflow for the design and production of these structures by the use of a parametric approach. (3) Design, production and assembly of a full-scale prototype in the form of a free-formed shell structure spanning an area of 20 m2. The prototype was made from fumed oak wood members in combination with white stained plywood panels connected by knots produced by Fused Filament Fabrication (FFF) additive manufacturing, using polymer-based materials and screws. At the end of the contribution, a summary and an outlook on further research is given.

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Journal articles on the topic 'Screws assembly'

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