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1
Sapiee, Siti Fairuz, and Hieng Ho Lau. "Influence of Screw Spacing on the Strength of Self-Drilling Screw Connection for the High Strength Cold-Formed Steel." Advanced Materials Research 712-715 (June 2013): 1054–57. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.1054.
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Self-drilling screws are the primary means of fastening for cold-formed steel members in cold-formed thin-gauge steel residential construction because it can drill their own holes and form their own threads. The fabrication of connections is the most labour intensive aspect of the cold-formed thin-gauge steel construction process, thus a better understanding of the behaviour of screw connections could lead to optimum connection design and reducing the cost of the fabrication. The study carried out to investigate the behaviour of single-shear connections using self-drilling screws in the cold-formed steel construction. The focus of this study is on the influence of the number of screws and screw spacing on the strength of self-drilling screw connection. These parameters are varied to determine their influences on the connection strength. The failure load and failure modes were obtained and observed from the tests carried out in the laboratory. Bearing and tilting failures occurred during the testing of these specimens. The predicted connection strengths were calculated using American Iron and Steel Institute (AISI) design equations. A total of 24 specimens of single shear test showed that connection strength is linearly proportional to the number of screw in the connection. Results of the specimen with spacing more than 3d show better correlation with the calculated results as compared to specimens with screw spacing less than 3d.
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Shi, Gang, Jian Xing Zhang, Yuan Qing Wang, Hui Juan Huang, and Zheng Hong Zhang. "Cooperation Pullout Test of Double Self-Tapping Screws in Wood Structures." Advanced Materials Research 374-377 (October 2011): 2520–24. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.2520.
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In this paper, the experimental study on the self-tapping screw’s pullout resistance in the wood structure was conducted. Domestic ordinary screws were used together with imported or domestic wood to fabricate 6 screw connection specimens in wooden walls. Then monotonic loading tests were conducted and it can be concluded that, the common round screw connection strength mainly depends on the failure mode, the lack of cooperation effect significantly influences the strength of screw connections, and the dispersion of screw connection stiffness is high. So, to obtain formulae for the self-tapping screw connection strength and stiffness by further experimental study will be very necessary.
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Tokuhashi, Yasuaki, Masashi Oshima, Yasumitsu Ajiro, and Hiroshi Uei. "A Novel Pedicle Screw with Mobile Connection: A Pilot Study." BioMed Research International 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/841958.
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To prevent adjacent disc problems after spinal fusion, a pedicle screw with a mobile junction between the head and threaded shaft was newly developed. The threaded shaft of the screw has 10 degrees mobility in all directions, but its structure is to prevent abnormal translation and tilting. This screw was evaluated as follows: (1) endurance test: 106times rotational stress was applied; (2) biological reactions: novel screws with a mobile head and conventional screws with a fixed head were inserted into the bilateral pedicles of the L3, L4, and L5 in two mini pigs with combination. Eight months after surgery, vertebral units with the screw rod constructs were collected. After CT scan, the soft and bony tissues around the screws were examined grossly and histologically. As a result, none of the screws broke during the endurance test stressing. The mean amount of abrasion wear was 0.0338 g. In the resected mini pig section, though zygapophyseal joints between fixed-head screws showed bony union, the amount of callus in the zygapophyseal joints connected with mobile-head screws was small, and joint space was confirmed by CT. No metalloses were noted around any of the screws. Novel screws were suggested to be highly durable and histologically safe.
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Pournasrollah, Alireza, Ramin Negahdari, Vahedeh Gharekhani, Ali Torab, and Soheil Jannati Ataei. "Investigating the effect of abutment–implant connection type on abutment screw loosening in a dental implant system using finite element method." Journal of Dental Research, Dental Clinics, Dental Prospects 13, no. 4 (December 23, 2019): 289–97. http://dx.doi.org/10.15171/joddd.2019.044.
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Background. The most common problem associated with dental implants is the abutment screw loosening. This research aimed to investigate the effect of the type of connection on screw loosening, using a finite element method (FEM). Methods. Periosave system and different types of the implant–abutment connection were used for modeling. After being measured, CAD files were modeled using CATIA software and imported to the ANSYS analysis software, and the model was loaded. Results. A force of 100 N was applied at 0.1 second, and no force was applied at 0.42 second. The screw head deformation at 0.1 and 0.42 seconds was 8 and 3.8 μm, and 7.6 and 2.8 μm at morse taper and octagon dental implant connections, respectively. The displacement rate of the internal surface of the abutment at 0.1 and 0.42 seconds was 10.7 and 8.4 μm, and 5.7 and 5.6 µm in the octagon and morse taper dental implant connections, respectively. The displacement of the implant suprastructure–abutment interface from the screw head at 0.1 and 0.42 seconds was 9 and 7 μm, and 7 and 6 μm in the morse taper and octagon dental implant connections, respectively. At intervals of 0 to 0.1 seconds and 0.6 to 0.8 seconds, the octagon connection was separated at the maximum screw head displacement and the internal part of the abutment, but the morse taper connection did not exhibit any separation. In the above time intervals, the results were similar to the maximum state in case of the minimum displacement of the screw head and the internal part of the abutment. Conclusion. Screw loosening is less likely to occur in the morse hex connection compared to the octagon connection due to the lack of separation of the screw from the internal surface of the abutment.
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Ng, Adeline Ling Ying, and Zhi Yong Law. "Experimental Study of Cold-Formed Steel Moment Connections with Screw Fasteners." Materials Science Forum 950 (April 2019): 85–89. http://dx.doi.org/10.4028/www.scientific.net/msf.950.85.
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A series of connection with screw fasteners were tested to study the behavior of cold-formed steel moment connection. The test specimens included hot-rolled parallel flange channels, cold-formed lipped C-Channels, and self-drilling self-fastening screws. Two different lipped C-Channels and a various number of screws per connection were used in this study. The moment-rotation behavior, rotational rigidity, and the connection capacity differed with the number of screws. The connection behaved as a pinned connection when 4 screws were used. However, local buckling was observed in the cold-formed steel sections near the connection when 8, 10 and 14 screws were used. The connection test results were compared with theoretical results calculated in accordance to the Australian Standards. None of the connection tested could achieve the moment capacity of the section connected.
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Marx, Alexander, Thomas Hutsch, Patrick Schiebel, Dirk Feltin, Frank Hoffmeister, Andreas Babbel, Thomas Weißgärber, and Axel Herrmann. "Sintered Connection - A Steel/CFRP Connection Module." Key Engineering Materials 809 (June 2019): 203–9. http://dx.doi.org/10.4028/www.scientific.net/kem.809.203.
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Nowadays, carbon fiber reinforced plastics (CFRP) are present in a variety of applications. However, it is still possible to maximize the potential of CFRP by creating multi-material designs of CFRP and metal. The key to success for multi-material designs is the joining technology. In this work a metal/carbon fiber connection module was develop. Carbon fibers (CF) were integrated with stainless steel by using a powder metallurgy approach. After this, the created connection module was integrated in a fiber layup, which was infiltrated with epoxy resin by a Resin Transfer Molding (RTM) process. Leveraging from this technology, a M6 thread-forming screw was chosen and added in the sintered body. The screw press out test indicated that the strength between the screw and the sintered body was above 11 kN, which can be still enhanced for future by thread optimization. Microscopic cut images and computer tomography (CT) were used to characterize the CF in the sintered steel body and to examine the border area between the two materials.
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Kaczmarek, Jakub, Tomasz Bartkowiak, Piotr Paczos, Bartosz Gapinski, Hanna Jader, and Martin Unger. "How Do the Locking Screws Lock? A Micro-CT Study of 3.5-mm Locking Screw Mechanism." Veterinary and Comparative Orthopaedics and Traumatology 33, no. 05 (June 26, 2020): 316–26. http://dx.doi.org/10.1055/s-0040-1709728.
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Abstract Objective To quantify the amount of the screw head thread and the plate hole thread connection in two 3.5 mm locking plates: Locking Compression Plate (LCP) and Polyaxial Locking System (PLS). Materials and Methods A micro - CT scan of a screw head - plate hole connection was performed pre- and post destructive tests. Tests were performed on bone surrogates in a fracture gap model. The 3.5 LCP and 3.5 PLS plates, with 3 perpendicular screws per segment were used in a destructive static test. The 3.5 PLS plates with mono- and polyaxial screws were compared in a cyclic fatigue tests in two orthogonal directions. Pre - and post - test scan datasets were compared. Each dataset was converted into serial images depicting sections cut orthogonally to locking screw axis. The amount of engagement was detected through automated image postprocessing. Results The mean amount of the thread connection for the LCP was 28.85% before and 18.55% after destructive static test. The mean amount of the connection for the PLS was 16.20% before and 14.55% after destructive static test. When inserted monoaxially, the mean amount of the connection for the PLS screws was 14.4% before and 19.24% after destructive cyclic test. The mean amount of the connection for the polyaxial inserted PLS screws when loaded against plate thickness was 2.99% before and 2.08% after destructive cyclic test. The mean amount of the connection for the polyaxial inserted PLS screws when loaded against plate width was 3.36% before and 3.93% after destructive cyclic test. The 3D visualization of the thread connection showed that the initial interface points between screw head and plate hole are different for both LCP and PLS after the destructive testing. Depending on the type of applied force, there was either loss or increase of the contact. Clinical Relevance Micro-CT offers news possibilities in locking implant investigation. It might be helpful in better understanding the nature of locking mechanism and prediction of possible mode of failure in different systems.
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Oh, Ji-Hyeon, Young-Seong Kim, Joong Yeon Lim, and Byung-Ho Choi. "Stress Distribution on the Prosthetic Screws in the All-on-4 Concept: A Three-Dimensional Finite Element Analysis." Journal of Oral Implantology 46, no. 1 (February 1, 2020): 3–12. http://dx.doi.org/10.1563/aaid-joi-d-19-00090.
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The all-on-4 concept, which is used to rehabilitate edentulous patients, can present with mechanical complications such as screw loosening and fracture. The purpose of this study was to evaluate the stress patterns induced in the prosthetic screws by the different prosthetic screw and abutment designs in the all-on-4 concept using finite element analysis. Von Mises stress values on 6 groups of each screw type, including short and narrow screw, short abutment; short and wide screw, short abutment; long and wide screw, short abutment; short and narrow screw, long abutment; short and wide screw, long abutment; and long and wide screw, long abutment, were compared under a cantilever loading of 200 N that was applied on the farther posterior to the position of the connection between the distal implant and the metal framework. Posterior prosthetic screws showed higher stress values than anterior prosthetic screws. The stress values in posterior prosthetic screws decreased as the length and diameter increased. In conclusion, the long and wide screw design offers advantages in stress distribution when compared with the short and narrow design.
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Wusqo, Urwatul, Ali Awaludin, Angga Fajar Setiawan, and Inggar Septhia Irawati. "Study of Laminated Veneer Lumber (LVL) Sengon to Concrete Joint Using Two-Dimensional Numerical Simulation." Journal of the Civil Engineering Forum 5, no. 3 (September 18, 2019): 275. http://dx.doi.org/10.22146/jcef.47694.
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The connection system is a critical part of Timber – Concrete Composite (TCC) floor structures. The behaviour of the connection needs to be known to predict the behaviour of composite structure accurately. Screws are one kind of connector that mostly used in the composite structure due to its installation ease and high withdrawal strength. This study carried out a two-dimensional numerical simulation to examine the behaviour of LVL Sengon-concrete joint using OpenSees software. The lag screw used to connect LVL Sengon and concrete. In this simulation, the screw was assumed as a beam with hinges element that supported by a set of springs representing the strength of LVL Sengon and concrete. Some input parameters for this simulation were obtained from the material test and previous research. The effect of secondary axial force was considered into the load-displacement curve resulted from the numerical simulation. This study performed several simulations towards the variation of the screw diameter, penetration depth, and concrete compressive strength. The capacity of the connections resulted from the numerical simulation were overestimates the manual calculation using EYM theory and NDS 2018 equations. The capacity of the connection increased about 146% to 284% due to the addition of secondary axial forces. In addition, this simulation can adequately predict the shear force, bending moment, and deformation of the screw. There is a plastic hinge formed in the screw after the screw being deformed a quite large. It shows the same yield mode with the manual calculation using EYM theory and NDS 2018 equations. This simulation also can show the contribution of each spring elements to resist the load until its ultimate strength.
10
Guo, Xiong, Lv Long Zou, Bing Lu, Shi Liang Zhang, Xing Ren Su, and Hui Xu. "Research on the Connection Performance of Variable Pitch of Screw Threaded Casing Based on 3D Finite Element Simulation Model." Applied Mechanics and Materials 215-216 (November 2012): 1105–10. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.1105.
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The connection performance of the large taper, multi-thread, variable pitch of screw threaded casing is researched by 3D finite element simulation on ANSYS Workbench. The 3D finite element model is created precisely. The stress distribution on the teeth of three kind variable pitch of screw threaded structure is studied by using the static structure of the contact analysis module. Contrasting stress distribution of the variable pitch of screw with of the equal pitch of screw under the same working condition, it is validated that design principle for the variable pitch of screw connection is correct. The influence of changes in the amount of variable pitch of screw to the whole stress distribution on teeth is discussed. The results show that the force distribution on the teeth of the variable pitch of screw connection is more uniform than equal pitch of screw, and will improve the overall carrying capacity. This study has its practical value to improve the connective performance of the threaded casing and enhance the product quality of threaded casing.
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Song, YJ, and SZ Li. "Leak detection for galvanized steel pipes due to loosening of screw thread connections based on acoustic emission and neural networks." Journal of Vibration and Control 24, no. 18 (July 11, 2017): 4122–29. http://dx.doi.org/10.1177/1077546317720319.
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Galvanized steel pipes with screw thread connections are widely used in indoor gas transportation. In contrast with the failure of pipe tubes, leakage in this system is prone to occur in the screw thread connections. Aiming at this specific engineering application, a method based on acoustic emission (AE) and artificial neural networks (ANNs) is proposed to detect small gas leaks. Experiments are conducted on a specifically designed galvanized steel pipe system with the manipulated leak occurring in the screw thread connection to acquire the raw AE data. The features in the time and frequency domains are extracted and selected to establish an ANN model for leak detection. It has been validated that the developed ANN-based leak detector can achieve an identification accuracy of over 98%. It is also verified that the proposed model is effective even when the AE signals due to a small leak pass over two screw thread connections or an elbow connection.
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Popovic, Mladjan, Milanka Djiporovic-Momcilovic, Jovan Miljkovic, and Ivana Gavrilovic-Grmusa. "The improvement of the edge screw connection in OSB and conventional particleboard." Bulletin of the Faculty of Forestry, no. 94 (2006): 257–66. http://dx.doi.org/10.2298/gsf0694257p.
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This work presents the method for improvement of direct screw connection performance in conventional particleboard (PB) and oriented strand board (OSB). It is conceived on adhesive insertion into the pilot hole prior to embedment of the screw. The tests were carried out on the PB and OSB, both presenting interior boards and with the same nominal thickness of 18 mm. Particleboard screws of the 5 mm in diameter were inserted in the edge of the board. Pilot hole diameters were 2,5 mm and 3,0 mm and the depth of embedment was 30 mm for all tests. The chosen PVAc adhesive (type 3) with the addition of wood flour as consolidator in the range from 3-10% was inserted into pilot-hole. Tests were also obtained after consequent reassembly of the screw connection in order to examine the ratio of loss in withdrawal forces in such case. It was found that the insertion of PVAc adhesive into the pilot hole and the addition of wood flour have the positive effects on the screw withdrawal force in the tested boards.
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Çetin, Engin, Mustafa Özkaya, Ümit Özgür Güler, Emre Acaroğlu, and Teyfik Demir. "Evaluation of the Effect of Fixation Angle between Polyaxial Pedicle Screw Head and Rod on the Failure of Screw-Rod Connection." Applied Bionics and Biomechanics 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/150649.
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Introduction.Polyaxial screws had been only tested according to the ASTM standards (when they were perpendicularly positioned to the rod). In this study, effects of the pedicle screws angled fixation to the rod on the mechanical properties of fixation were investigated.Materials and Method.30 vertically fixed screws and 30 screws fixed with angle were used in the study. Screws were used in three different diameters which were 6.5 mm, 7.0 mm, and 7.5 mm, in equal numbers. Axial pull-out and flexion moment tests were performed. Test results compared with each other using appropriate statistical methods.Results.In pull-out test, vertically fixed screws, in 6.5 mm and 7.0 mm diameter, had significantly higher maximum load values than angled fixed screws with the same diameters (P<0.01). Additionally, vertically fixed screws, in all diameters, had significantly greater stiffness according to corresponding size fixed with angle (P<0.005).Conclusion.Fixing the pedicle screw to the rod with angle significantly decreased the pull-out stiffness in all diameters. Similarly, pedicle screw instrumentation fixed with angle decreased the minimum sagittal angle between the rod and the screw in all diameters for flexion moment test but the differences were not significant.
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Hranilović, Igor, Darko Meštrović, Zsolt Kokrehel, and Dean Čizmar. "Screw Connection in Reinforced Concrete Column Joints of Prefabricated Structures." Solid State Phenomena 259 (May 2017): 249–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.259.249.
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Classic connection between prefabricated reinforced concrete columns on a foundation slab using the concrete plinth base can sometimes be very problematic, especially in limited construction conditions and / or foundation on sandy terrain where the groundwater is very close to the ground surface. By applying the screw connection between a prefabricated reinforced concrete column and the foundation structure using anchor bolts and column shoes, the overall height of the foundation is successfully reduced. The established connection between prefabricated reinforced concrete column and the foundation can immediately sustain the design force after assembly and it is considered to be a rigid connection that acts as an equivalent conventional connection with concrete plinth base, without any other additional support and welding. The successful implementation is possible with underground levels of structures where the inverted concrete plinth bases are implemented - the indentation in the foundation slab for the connection of prefabricated columns with base plate is avoided.Application of the screw connection also enables the design of the continuation of the column at higher altitude (column to column) or connection of the upper part the element with the monolithic structure. Screw connection is particularly suitable for use in seismic areas because the performed tests showed very good ductility of the connections under cyclic load.
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Zhang, Dongmei, Shiqiao Gao, and Xiao Xu. "A new computational method for threaded connection stiffness." Advances in Mechanical Engineering 8, no. 12 (December 2016): 168781401668265. http://dx.doi.org/10.1177/1687814016682653.
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For designing bolted connections in machinery applications, it is necessary to estimate the stiffness of the threaded connection. This work provides a new method for computing the stiffness of engaged screw in bolted connections according to the load distribution in screw thread. Finite element analysis is performed by building the three-dimensional model of threaded connection. A set of tensile tests are exerted to validate the accuracy of the suggested model of threaded connection. A good agreement is obtained when the analytical results are compared with finite element analysis results, experimental data, and Yamamoto method. Results reveal that the ultimate strength of thread connections is obviously lower than that of thread material. In addition, the results of calculation and finite element analysis indicated that increasing Young’s modulus of material and the engaged length or decreasing thread pitch could increase the stiffness of the thread portion of a bolt and nut.
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Wang, Shen Wei, and Cheng Jiang Wang. "Design Method on Shear Behavior of Single Tapping Screw Connections in Cold-Formed Thin-Wall Steel Structures." Applied Mechanics and Materials 351-352 (August 2013): 691–94. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.691.
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In order to investigate the design method of single tapping screw connections between steel plate and non-steel plate and the applicability of calculating the shear capacity of single tapping screw connections with sheet steel under 2mm according to Chinese code Technical code for design of cold-formed thin-wall steel structures(GB50018-2002),theoretical analysis was carried out on single tapping screw connections, which were distinguished by connection forms called steel plate-steel plate connections and steel plate-non-steel plate connections. The results show that: Chinese code GB50018-2002 is suited to calculate the shear capacity of single tapping screw connections with sheet steel under 2mm and the results are safe compared with test results. The design method of single tapping screw connections between steel plate and non-steel plate is given on the basis of test results.
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Acharya, Sandesh R., and K. S. Sivakumaran. "Finite Element Models for Thin-Walled Steel Member Connections." ISRN Civil Engineering 2012 (December 30, 2012): 1–7. http://dx.doi.org/10.5402/2012/197170.
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The behavior of connections associated with the thin-walled steel members is distinctly different from that of hot-rolled steel connections, primarily because of the flexibility of the plates. A typical cold-formed steel structural construction may entail such numerous connections. The incorporation of large number of such connections in an analysis and design, using sophisticated finite element models, is very tedious and time consuming and may present computational difficulties. The objective of this investigation is to create simplified, yet reasonably accurate, finite element models for the analysis of screw connections and bolted connections associated with thin-walled sheet steel construction. The primary plates were modeled using quadrilateral shell elements, and nonlinear stress-strain relationship was established based on experiments. The fasteners were modeled as an elastic medium. The plate-to-plate interactions and the plate-to-screw interactions were incorporated using contact elements. The study considered two finite element models of different complexity. The performance of these models was established through comparisons with the corresponding experimental results. The finite element analysis results exhibit reasonably good agreement with the test results in terms of connection stiffness, screw tilting, end curling, and average longitudinal strain. The recommended simplified connection model is capable of reproducing the behavior of sheet steel screw and bolt connections.
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Huang, Wei Lei, and Gui Cheng Wang. "Strength of Screw Thread in Vibration Tapping." Advanced Materials Research 443-444 (January 2012): 678–83. http://dx.doi.org/10.4028/www.scientific.net/amr.443-444.678.
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Screw thread connection is a common way of detachable connection. The invalidation of screw thread connection will lead to mechanical failure or even retirement. Vibration tapping is essentially a kind of high-energy impact cutting which increases the rigidity of the tool. Composite vibration tapping simultaneously with repeated cutting action reduces the surface recovery of plastic materials and enhances metal cutting rate. Theoretical study and experimental results show that vibration tapping improves the metal cutting rates, enhances the machining accuracy and makes screw thread connection assembly easier. At the same time, vibration tapping process does not reduce the strength of screw thread. As the screw thread can be more uniformed cut at different depths, vibration tapping enhances the strength of screw thread slightly.
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Seo, Soo Yeon, Seung Joe Yoon, and Sang Koo Kim. "Tensile Capacity of Mechanical Bar Connection Corresponding to Detail of Screw on Bar Surface for Construction." Applied Mechanics and Materials 236-237 (November 2012): 693–96. http://dx.doi.org/10.4028/www.scientific.net/amm.236-237.693.
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This study is intended to investigate the performance depending on the screw type at the end part of reinforcement in the mechanical connection of high strength reinforcement with screws. Three types of mechanical connection were designed and tensile test was performed for those. The results presented that, although the end part of reinforcement was processed with screws, the reinforcement’s yield and tensile strength sufficiently appeared. But, its plastic deformation capacity after yielding fell 17~26% more than reinforcement.
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Martynyuk, V. A., V. A. Trudonoshin, and V. G. Fedoruk. "A Mathematical "Screw-Nut" Connection Model for the Universal Software to Analyse Dynamical Systems." Mechanical Engineering and Computer Science, no. 10 (November 20, 2017): 1–12. http://dx.doi.org/10.24108/1017.0001314.
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The article deals with a mathematical model of the "screw-nut" connection adapted for using in universal software systems to analyse dynamic characteristics. This article is sequel to a number of earlier authors-written articles devoted to object simulation of 3D mechanics. Such a model available in the library of mathematical models of the modelling system will significantly extend the list of simulated mechanisms. The mathematical model of "screw-nut" connection suggests such a connection between absolutely rigid bodies. The "screw-nut" connection parameters are the following:thread pitch by the radian of the angle of pitch;coordinates of the point on the axis of the screw in the local coordinate system of the body 1;direction cosines of the screw axis in the local coordinate system of the body 1.Note that the connection parameters have constant values. Two drawbacks of this model should be noted.1. Some expressions of the mathematical model involve dividing by direction cosine of the screw axis thereby eliminating "division by zero" when the axis of the screw is perpendicular to the x-axis of the global coordinate system. The software-based way allows eliminating this shortcoming.2. The model does not include coordinates of mass centres of bodies tied by connection. This can lead to a significant "mismatch" in the position of the bodies in modelling of multi- periodic transient processes. However, adding an elastic model to the mathematical model can eliminate this drawback.The article demonstrates the "screw-nut" connection model to simulate a jack using the PA8 system and comparing its results with those obtained with help of the NX10 complex. Gives, in addition, the results of influence in terms of dry friction in the "screw-nut" connection. Taking into consideration the dry friction allows us to reflect the effect of "self-stopping" in the jack.
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Mohd Sani, Mohd Syahrul Hisyam, Fadhluhartini Muftah, Ahmad Rasidi Osman, and Cher Siang Tan. "Mechanical Behaviour for Connection of Cold-Formed Steel Channel Section with Intermediate Web Stiffener." Key Engineering Materials 792 (December 2018): 153–59. http://dx.doi.org/10.4028/www.scientific.net/kem.792.153.
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Cold-formed steel (CFS) is a popular steel-based material for building such as roof truss system and wall frame panel. CFS with a variety of shapes, cross-sections and thickness produce a lot of advantages such as ease of production, corrosion resistance and high strength to weight ratio. Connection of the CFS sections between them uses screw, bolt and nut, rivet or weld. But, the detail information for the connector in standard either by Eurocode 3 or American Iron and Steel Institute (AISI) is still incomplete especially methods for testing and also lack in the basic knowledge of testing for the connector or combination of connectors. The connector that was used in this study was a self-drilling screw. The objective of the study is to provide the mechanical behaviour information of self-drilling screws from shear and pull-out tests. Both tests utilised Universal Testing Machine with 100 kN capacity to determine the ultimate load and load-deformation behaviour of the self-drilling screws with different numbers. As a result, the ultimate load of the specimen was found to increase with increasing number of the self-drilling screws for shear and pull-out connection tests.
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Lu, Lin Feng, Ya Ping Zhang, Wen Qi Fang, and Dong Hua Yang. "Research Progress and Prospect on Self-Drilling Screw Connection Shear Capacity." Applied Mechanics and Materials 166-169 (May 2012): 187–93. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.187.
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Recently, self-drilling screw connection is the most primary connection way in the cold-formed thin-wall steel structure, many scholars have studied its stress mechanism and shear capacity. This paper begins with several self-drilling screw stress mechanism and shear failure mode, introduces the domestic and international calculation, then summarize and analyze the research progress on the self-drilling screw. At last, prospect on the self-drilling screw shear capacity and application.
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Ikhsan, Muhammad Nur, Ali Awaludin, and Andreas Triwiyono. "KUAT TARIK DAN POLA KEGAGALAN KOMBINASI SAMBUNGAN BAUT DAN SEKRUP PADA BAJA CANAI DINGIN." INERSIA: lNformasi dan Ekspose hasil Riset teknik SIpil dan Arsitektur 16, no. 2 (December 24, 2020): 144–57. http://dx.doi.org/10.21831/inersia.v16i2.36900.
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ABSTRAK Saat ini, material Cold Formed Steel (CFS) lebih umum digunakan karena kekuatan tariknya yang diketahui daripada material Hot Rolled Steel (HRS). Bahan konstruksi CFS tidak hanya digunakan untuk fungsi struktur atap, tetapi juga banyak digunakan sebagai struktur bangunan. Perilaku koneksi kombinasi baut dan sekrup CFS diidentifikasi untuk mengetahui jenis kegagalan dan kapasitas sambungan. Beban maksimum pengujian tarik diterapkan pada dua jenis bahan CFS. Spesimen dalam penelitian ini terdiri dari dua variasi ukuran lembar CFS 40 mm x 340 mm dan 40 mm x 360 mm. Lembar pertama digunakan untuk sambungan sekrup, baut dilengkapi ring, dan baut tanpa ring. Lembar kedua digunakan untuk sambungan kombinasi sekrup dengan baut tanpa ring dan sambungan kombinasi sekrup dengan baut dilengkapi ring. Hasil penelitian menunjukkan bahwa nilai slip spesimen sambungan baut dilengkapi ring lebih besar daripada spesimen sambungan baut tanpa ring. Nilai kapasitas tarik yang diperoleh dari koneksi kombinasi baut dengan washer dan sekrup lebih besar daripada yang tanpa ring dengan sekrup. Pola kegagalan pengujian tarik adalah kegagalan sobek dan kegagalan patah. Kata kunci: kombinasi, sambungan, baut, sekrup, CFS ABSTRACTNowadays, Cold Formed Steel (CFS) materials is more commonly used because of its known tensile strength than Hot Rolled Steel (HRS) material. CFS construction material is not only used for roof structures function, but also widely used as building structures. The behavior of bolt and screw combination connections of CFS was identified to know the type of failure and connection capacity. A maximum load of tensile testing was applied to two type of CFS materials. The specimens in this study consisted of two variations CFS sheet sizes 40 mm x 340 mm and 40 mm x 360 mm. The first sheet is used for screw connectors, bolt with washers, and bolt without washers. The second sheet is used for screw connectors combined with bolts without washer and screw connectors combined with bolts and washer. The results showed that the slip value of the bolt connection specimens with washers was greater than the bolt connection specimens without washer. The tensile capacity value obtained by the bolt combination connection with washer and screw was more rodust than the one without washer and screw. The failure patterns of tensile testing were a pull-through and fracture failures. Keywords: combination, connection, bolt, screw, CFSABSTRAK Saat ini, material Cold Formed Steel (CFS) lebih umum digunakan karena kekuatan tariknya yang diketahui daripada material Hot Rolled Steel (HRS). Bahan konstruksi CFS tidak hanya digunakan untuk fungsi struktur atap, tetapi juga banyak digunakan sebagai struktur bangunan. Perilaku koneksi kombinasi baut dan sekrup CFS diidentifikasi untuk mengetahui jenis kegagalan dan kapasitas sambungan. Beban maksimum pengujian tarik diterapkan pada dua jenis bahan CFS. Spesimen dalam penelitian ini terdiri dari dua variasi ukuran lembar CFS 40 mm x 340 mm dan 40 mm x 360 mm. Lembar pertama digunakan untuk sambungan sekrup, baut dilengkapi ring, dan baut tanpa ring. Lembar kedua digunakan untuk sambungan kombinasi sekrup dengan baut tanpa ring dan sambungan kombinasi sekrup dengan baut dilengkapi ring. Hasil penelitian menunjukkan bahwa nilai slip spesimen sambungan baut dilengkapi ring lebih besar daripada spesimen sambungan baut tanpa ring. Nilai kapasitas tarik yang diperoleh dari koneksi kombinasi baut dengan washer dan sekrup lebih besar daripada yang tanpa ring dengan sekrup. Pola kegagalan pengujian tarik adalah kegagalan sobek dan kegagalan patah. Kata kunci: kombinasi, sambungan, baut, sekrup, CFS ABSTRACTNowadays, Cold Formed Steel (CFS) materials is more commonly used because of its known tensile strength than Hot Rolled Steel (HRS) material. CFS construction material is not only used for roof structures function, but also widely used as building structures. The behavior of bolt and screw combination connections of CFS was identified to know the type of failure and connection capacity. A maximum load of tensile testing was applied to two type of CFS materials. The specimens in this study consisted of two variations CFS sheet sizes 40 mm x 340 mm and 40 mm x 360 mm. The first sheet is used for screw connectors, bolt with washers, and bolt without washers. The second sheet is used for screw connectors combined with bolts without washer and screw connectors combined with bolts and washer. The results showed that the slip value of the bolt connection specimens with washers was greater than the bolt connection specimens without washer. The tensile capacity value obtained by the bolt combination connection with washer and screw was more rodust than the one without washer and screw. The failure patterns of tensile testing were a pull-through and fracture failures. Keywords:combination, connection, bolt, screw, CFS
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Kumpenza, Cedou, Andreas Ringhofer, Thomas Krenke, Adeayo Sotayo, Maximilian Pramreiter, and Ulrich Müller. "Timber screw connection: Study of the strain along the interface using optical measurement techniques and simulations." BioResources 15, no. 2 (April 6, 2020): 3859–73. http://dx.doi.org/10.15376/biores.15.2.3859-3873.
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In various engineering applications, self-tapping screws are used to connect timber members. To describe their load-deformation relationship, a better understanding of the strain along the mechanical interface (i.e., timber-screw interface) is required. With a focus on the axial loading of self-tapping screws, only a few studies have dealt with the determination of the strain based on optical measurement techniques. Therefore, in the present study, the strain distribution at the timber-screw interface was monitored during pull-out tests using an optical measurement technique, called electronic speckle pattern interferometry (ESPI). Strains obtained from the ESPI measurements were compared with the results obtained from structural simulations conducted with finite element modelling (FEM). Three different types of solid spruce wood (Picea abies (L.) Karst.) specimens with different grain orientations connected with self-tapping screws (thread length lg = 130 mm, outer thread diameter d = 12 mm) were tested in withdrawal. There was a good agreement between the ESPI and FEM results, confirming that ESPI was a suitable measurement technique. The study also provided insights and results regarding the region of strain concentrations across the length of self-tapping screws.
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Vélez, Jorge, Jesús Peláez, Carlos López-Suárez, Rubén Agustín-Panadero, Celia Tobar, and María J. Suárez. "Influence of Implant Connection, Abutment Design and Screw Insertion Torque on Implant-Abutment Misfit." Journal of Clinical Medicine 9, no. 8 (July 24, 2020): 2365. http://dx.doi.org/10.3390/jcm9082365.
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Background: An accurate fit at the implant-abutment interface is an important factor to avoid biological and mechanical complications. The aim of this study was to evaluate the marginal misfit at the implant-abutment interface on external and Morse taper connection, with straight and angulated abutments under different insertion torque loads. Materials and Methods: A total of 120 implants were used, 60 with external connection (EC) and 60 with Morse taper connection (IC). Straight (SA) (n = 60) and angulated abutments (AA) (n = 60) were randomly screwed to each connection at different torque levels (n = 10 each): 10, 20 and 30 Ncm. All specimens were subjected to thermal and cyclic loading and the misfit was measured by scanning electron microscopy. Data were analyzed with one-way ANOVA, t-test and Kruskal-Wallis test. Results: Significant differences (p < 0.001) were found between connections and abutments regardless of the torque applied. Morse taper connections with straight and angulated abutments showed the lowest misfit values (0.6 µm). Misfit values decreased as torque increased. Conclusions: The misfit was affected by the type of connection. The type of abutment did not influence the fit in the Morse taper connection. The higher the tightening torque applied the increase in the fit of the implant-abutment interface.
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Kim, Ji-Sun, Young-Bum Park, Hynmin Choi, Sungtae Kim, Hyeon Cheol Kim, Sun Jai Kim, Hong-Seok Moon, and Jae-Hoon Lee. "Influence of internal connection length on screw loosening in internal connection implants." Journal of Korean Academy of Prosthodontics 55, no. 3 (2017): 251. http://dx.doi.org/10.4047/jkap.2017.55.3.251.
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Sun, Fu. "Analysis of the Screw Thread Connection Strength Based on Nonlinear Finite Element Method." Applied Mechanics and Materials 401-403 (September 2013): 55–58. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.55.
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Some parts of the projectile is in screw connection, the stress and deformation caused by screw threads are important indexes of the security, and therefore stress distribution of the connection of thread must be accurately calculated. According to the structural characteristics of threaded connection, nonlinear finite element contact analysis was used, strength of the thread connection part was simulated and analyzed by applying effective loads, and this algorithm was validated.
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Sun, Fu, Xiao Lei Wu, Shi Feng Yao, and Guang Ye Liang. "Simulation of the Screw Thread Connection Temperature Field Based on ANSYS." Applied Mechanics and Materials 440 (October 2013): 204–9. http://dx.doi.org/10.4028/www.scientific.net/amm.440.204.
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Friction of screw thread connection will cause temperature rise while projectile unloading, Too high temperature which would cause the combustion will result in significant safety issues, so the temperature field of screw thread connection must be analyzed when the projectile unloading. But friction is a complex process, how to simulate the temperature change accurately is the key link of the whole analysis. In this paper, friction of the screw thread surface in the process of unloading is simulated based on thermal analysis function of ANSYS. According to temperature distribution of the screw thread surface, the highest temperature and position of the highest temperature point is determined. The relationship between temperature and different speed is analyzed, which can provide a theory basis for safely unloading.
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BASTOS, Juliana Maria Coutinho, Dimorvan BORDIN, Andréa Araújo de VASCONCELLOS, and Milton Edson MIRANDA. "Influence of cantilever position and implant connection in a zirconia custom implant-supported fixed partial prosthesis: in silico analysis." Revista de Odontologia da UNESP 47, no. 4 (August 27, 2018): 223–29. http://dx.doi.org/10.1590/1807-2577.06718.
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Abstract Introduction A better tension distribution on implants and abutments in implant-supported fixed partial prosthesis is essential in the rehabilitation of posterior mandible area. Objective: To evaluate the influence of cantilever position and implant connection in a zircônia custom implant-supported fixed partial prosthesis using the 3-D finite element method. Material and method: Four models were made based on tomographic slices of the posterior mandible with a zirconia custom three-fixed screw-retained partial prosthesis. The investigated factors of the in silico study were: cantilever position (mesial or distal) and implant connection (external hexagon or morse taper). 100 N vertical load to premolar and 300 N to molar were used to simulate the occlusal force in each model to evaluate the distribution of stresses in implants, abutments, screws and cortical and cancellous bone. Result: The external hexagon (EH) connection showed higher cortical compression stress when compared to the morse taper (MT). For both connections, the molar cantilever position had the highest cortical compression. The maximum stress peak concentration was located at the cervical bone in contact with the threads of the first implant. The prosthetic and abutment screws associated with the molar cantilevers showed the highest stress concentration, especially with the EH connection. Conclusion: Morse taper implant connetions associated with a mesial cantilever showed a more favorable treatment option for posterior mandible rehabilitation.
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Martínez, José María Rico, and Joseph Duffy. "A general method for the computation of the canonical form of three-systems of infinitesimal screws." Robotica 16, no. 1 (January 1998): 37–45. http://dx.doi.org/10.1017/s0263574798000137.
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A general method for the computation of the canonical form of three-systems of infinitesimal screws is presented. The method is particularly simple when the three-system has a basis that is simultaneously perpendicular and reciprocal. However, it can also handle the special or degenerate cases. The method and the concurrent results are important from the theoretical point of view because of the obvious connection with the classification of screw-systems. Moreover, the results are also important for applied kinematics after recent applications of the canonical form of screw-systems to the analysis and synthesis of manipulators and manipulator substructures.
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Krenn, Michael Hannes, Wolfgang Peter Piotrowski, Rainer Penzkofer, and Peter Augat. "Influence of thread design on pedicle screw fixation." Journal of Neurosurgery: Spine 9, no. 1 (July 2008): 90–95. http://dx.doi.org/10.3171/spi/2008/9/7/090.
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Object The authors conducted a study to determine the thread properties that provide optimal screw fixation in cancellous bone, when screws of the same external screw diameter are used. Methods Three compliance engineering–certified screws in clinical use, all of the same external diameter and length, were compared in an axial pullout experiment with respect to advantageous thread properties. As test material, standardized Sawbone blocks with 3 different densities (0.12, 0.16, and 0.32 g/cm3) were used. Results Screw thread Type 1, whose flank overlap area (FOA; 261 mm2) results from narrowing the conical core in the thread area, showed significantly better holding strength than the other types. Screw thread Type 2 (FOA 326 mm2) with a conical but thicker core and a smaller thread pitch was found to be the only one without increase of pull-out forces when test materials density changed from 0.12 to 0.16 g/cm3. A screw tested as control, with a constant (cylindrical) core diameter (Type 3; FOA 206 mm2), had the same thread pitch as Type 1 but without the compressive effect on the surrounding bur hole wall material. Nevertheless, it showed higher pullout forces in the 0.16-g/cm3 material than screw Type 2. Conclusions By reducing the core diameter of a screw toward the tip, while maintaining a constant nominal (external) diameter, one achieves frictional connection due to compression of surrounding material. In addition, the FOA is increased, which, in summary, leads to better fixation, as shown by screw Type 1.
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Fong, Lee Yen, Nor Hayati Abd Ghafar, Norashidah Abd Rahman, and David Yeoh. "Connection Performance for LVL-Concrete Composite Floor System." Applied Mechanics and Materials 773-774 (July 2015): 954–63. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.954.
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The LVL-concrete composite (LCC) structure is a hybrid in system which the LVL member is well connected to the concrete slab by a connector to produce composite action. Various types of connector with different stiffness and shear capacity are available in the market currently. The stiffness of the connector is identified through the push-out experiment. The notch connections for LVL concrete composite beams have higher stiffness and strength compared to mechanical fasteners. This paper discusses the experimental results of symmetrical push-out tests on 3 different types of connector, 150mm rectangular notch with 10mm diameter screw, 100mm rectangular notch with 8mm diameter screw and 100mm triangular notch with 8mm diameter screw. The experimental test was shear push out to failure and the type of failure was discussed. The 150mm rectangular notch was found to be strongest among all and low cost. The 100mm rectangular notch was found to be slightly stiffer than 100mm triangular notch but 100mm triangular notch is easier to construct with only 2 cut. The maximum strength and stiffness at ultimate limit states and serviceability limit states of each type of connection were discussed in this paper.
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Chung, Chae Heon, Han Cheol Choe, Hee Jung Kim, Jin Sup Kim, and William A. Brantley. "Mechanical Joint of Abutment/Fixture Screw Interface in the Internal Dental Implant System." Key Engineering Materials 345-346 (August 2007): 1417–20. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1417.
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To investigate mechanical fitness of abutment/fixture screw interface in the internal dental implant system, internal connection type implants from AVANA(Osstem®), Bioplant(Cowell-Medi®), Dio(DIO®), Neoplant(Neobiotech®), systems were used in this study. Each group was acquired 2 fixtures at random. Two piece type abutment and one piece type abutment for use with each implant system were acquired. Screw was respectively used to hold a two piece type abutment to a implant fixture. All samples were cross-sectioned with grinder-polisher unit and all specimens were analyzed the interface phenomena between implant fixture/abutment/screw contact interfaces by using field emission scanning electron microscope(FE-SEM). Implant fixture/abutment/screw connection interfaces of internal connection systems made in Korea were in good condition. The results of the above study showed that materials and mechanical properties and quality of milling differed depending on their manufacturing companies.
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Siadat, Hakimeh, Hossain Najafi, Marzieh Alikhasi, Babak Falahi, Elaheh Beyabanaki, and Farid Zayeri. "Effect of lateral oblique cyclic loading on microleakage and screw loosening of implants with different connections." Journal of Dental Research, Dental Clinics, Dental Prospects 12, no. 3 (October 26, 2018): 183–89. http://dx.doi.org/10.15171/joddd.2018.028.
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Background. The implant connection type might affect microleakage and screw loosening in two-piece implants. The aim of this study was to measure microleakage and screw loosening of two connections of Noble Biocare implant system before and after cyclic loading. Methods. Twelve samples were categorized into two groups: external hexagon (Branemark) and internal hexagon connection (Noble Active) and two implants as controls. The abutments were tightened to a 35 Ncm torque. Initial torque loss (ITL) was measured five minutes after retightening the abutment, using a digital torque wrench. The samples were covered with putty material to the abutment‒implant junction. Customized metal crowns with 45° inclinations were placed on the abutments and cyclic loading was performed accordingly. Thereafter, the secondary torque loss (STL) was measured. Microleakage test was also performed. Data were analyzed with Mann-Whitney and Wilcoxon tests (α=0.05). Results. There were no statistically significant differences between the two phases of gamma counting between and within two groups (P>0.05). However, STL after cyclic loading was less than ITL in both groups (P=0.042). Conclusion. Connection type and cyclic loading had no significant effect on microleakage. Furthermore, the internal connection had less TL as compared to the external connection. In addition, the STLs were less than ITLs in both groups.
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LaBelle, James C., J. Randolph Kissell, and Tanya A. Dolby. "Pull-Out Strength of Screws in Screw Chases: Part 2." Key Engineering Materials 710 (September 2016): 121–26. http://dx.doi.org/10.4028/www.scientific.net/kem.710.121.
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This paper (Part 2 of 2) presents a study of the structural behavior of tension-loaded screws installed in screw chases in extruded aluminum profiles. This connection is commonly used to resist outward wind load on glass in curtainwalls and skylights. See Part 1 for details of the pull-out testing. Two types of chase, each with 1/4 in. (6.35 mm) diameter stainless steel screws were used: a flat chase with AB tapping screws (1/4-14; 14 threads per 25.4 mm) and F tapping screws (1/4-20; 20 threads per 25.4 mm), and a longitudinally ribbed chase with UNC-thread machine screws (1/4-20). The extrusions included six cross-section shapes (three with flat chases and three with ribbed chases) and three alloy-tempers.
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Aparecido de Oliveira, Tiago, Ródney Silvério Costa Junior, Wesley Cândido Silva, and André Luís Gamino. "COMPARATIVO DE DIMENSIONAMENTO PARA EXECUÇÃO ENTRE LIGAÇÕES PARAFUSADAS POR MEIO DE PARAFUSOS DE ALTA RESISTÊNCIA E LIGAÇÕES SOLDADAS COM ELETRODO REVESTIDO." COLLOQUIUM EXACTARUM 10, no. 4 (December 1, 2018): 44–52. http://dx.doi.org/10.5747/ce.2018.v10.n4.e255.
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The steel industry offers a wide variety of options for using steel in construction, such as thin steel, sheet metal, screws, welding materials, bars, cables, cables among others, thus making it possible to build a metal structure . Thinking about the construction of the same, then we imagine as the unions of the parts of the structure. Taking this into consideration, the present work has as scope the design of an industrial shed structured in steel, with the purpose of demonstrating how the beams-abutmentsand beam-beams connections do not even present, when screwing with high resistance screws ASTM A325, and welded connections with coated electrode. The advantages and disadvantages of the two processes were explained for a better connection to the proposedcase. A theoretical analysis of the two cases was carried out, followed by sizing and checking to obtain an indication of the type of A325 high strength screw support for a section labeled and size and type of weld for the crimped section.
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Zha, Xiao Xiong, and Zhi Rong Tang. "Research on Tensile Bearing Capacity of Self-Drilling Screw Joints for Thick Faced Roof Sandwich Panels." Advanced Materials Research 859 (December 2013): 122–26. http://dx.doi.org/10.4028/www.scientific.net/amr.859.122.
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To find out the connection of screw joints and base materials or the metal crest surface at the head of screw which is destroyed first, the tensile bearing capacity of joints between self-drilling screws (SDS) and the base materials were tested first. With two types of SDS joints furnished with C-saddle washers (C-SW) and M-saddle washers (M-SW) respectively, test and analysis on the tensile bearing capacity of SDS joints were undertaken. Corresponding finite element (FE) models were analyzed by ANSYS/LS-DYNA software. Based on mechanical analysis, a new theoretically computational formula for tensile bearing capacity of SDS joints is proposed.
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Ohya, Junichi, Todd D. Vogel, Sanjay S. Dhall, Sigurd Berven, and Praveen V. Mummaneni. "Technique and nuances of an S-2 alar iliac screw for lumbosacral fixation in patients with transitional and normal anatomy." Neurosurgical Focus 41, videosuppl1 (July 2016): 1. http://dx.doi.org/10.3171/2016.2.focusvid.1690.
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S-2 alar iliac (S2AI) screw fixation has recently been recognized as a useful technique for pelvic fixation. The authors demonstrate two cases where S2AI fixation was indicated: one case was a sacral insufficiency fracture following a long-segment fusion in a patient with a transitional S-1 vertebra; the other case involved pseudarthrosis following lumbosacral fixation. S2AI screws offer rigid fixation, low profile, and allow easy connection to the lumbosacral rod. The authors describe and demonstrate the surgical technique and nuances for the S2AI screw in a case with transitional S-1 anatomy and in a case with normal S-1 anatomy.The video can be found here: https://youtu.be/Sj21lk13_aw.
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Sønstabø, Johan Kolstø, David Morin, and Magnus Langseth. "Macroscopic Modelling of Flow-Drill Screw Connections." Key Engineering Materials 710 (September 2016): 143–48. http://dx.doi.org/10.4028/www.scientific.net/kem.710.143.
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This study focuses on the modelling of Flow-Drill Screw (FDS) connections in large-scale shell analyses. Macroscopic connection models for large-scale crash simulations were assessed for modelling of FDS connections between two aluminium plates. Of the investigated models were two commercial element-based and three commercial constraint-based models, as well as two new user-defined element-based models. All models were calibrated using cross tests in tension, shear and a mixed shear/tension mode. In order to assess the flexibility of the models two sets of experimental data were used. In the first one, a small screw was used to join two sheets of the same rolled alloy while the second set used a longer screw with a larger head to join a rolled alloy to an extrusion. The calibrated models were validated using a two-step approach involving benchmark and component tests. Of the commercial models, the constraint-based performed better than the element-based. The new user-defined models gave similar results as the commercial constraint-based models. From the obtained results, recommendations for modelling of FDS connections for large-scale analyses were formulated.
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Kavaliauskas, Saulius, Audronis Kazimieras Kvedaras, and Balys Valiūnas. "MECHANICAL BEHAVIOUR OF TIMBER‐TO‐CONCRETE CONNECTIONS WITH INCLINED SCREWS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 13, no. 3 (September 30, 2007): 201–7. http://dx.doi.org/10.3846/13923730.2007.9636437.
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The purpose of this paper is to adopt the Johansen's yielding theory as a possibility to predict the ultimate load for timber‐to‐concrete joints using self‐tapping threaded connectors screwed at an angle into the wood. The ultimate load‐bearing capacity of a single connector is predicted to be when either the stresses in the wood reach the plastic failure stress level or when a combination of plastic failure in wood and dowel is attained. K. W. Johansen assumed that no axial tension occurred in the dowel and, thus no frictional contribution affected the lateral load‐bearing capacity. However, the joints with inclined fasteners are first affected by tension load, so the withdrawal capacity of the screws has to be taken into account. In order to determine the load bearing capacity for specific connector geometry, the kinematical possible failure modes are determined. The screw in the concrete part of connection was taken as rigidly embedded and thus no deformations appeared. The study showed that the load‐bearing capacity for connections with inclined high tensile strength screws can be predicted using the yielding theory, but this theory was unable to predict precisely the failure mode. Possible reasons for that include limited fastener ductility and influence of the screw inclination on the strength properties of timber.
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Sacker, Thamiris Nogueira, Micheline Sandini Trentin, Thais Maria Pires dos Santos, Ricardo Tadeu Lopes, and Elken Gomes Rivaldo. "In vitro microtomography evaluation of the implant-abutment interface - Gap microtomography evaluation/ Avaliação da microtomografia in vitro da interface implante-pilar - Avaliação da microtomografia de Gap." Brazilian Journal of Development 7, no. 6 (June 13, 2021): 57552–65. http://dx.doi.org/10.34117/bjdv7n6-249.
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Objectives: To evaluate in vitro the micromorphological differences of the prosthetic implant-abutment interface in two screw implant systems and a friction one.Materials and methods: Two screw implants (Group 1- Crossfit Internal Connection, Group 2- Tapered Internal Connection), a compressed friction implant (Group 3 - Frictional Connection), and their corresponding prosthetic components were used. The implants were individually fixed in an acrylic resin cylinder and the abutments were positioned with the torque recommended by the manufacturer and taken into a SkyScan 1173 microtomograph. In each implant-abutment image, the regions of interest evaluated were cervical area, abutment area, screw area, and abutment and screw area (G1-G2). In group 3, the cervical and abutment areas were measured. Statistical analysis was performed with ANOVA, Robust ANOVA, and Post Hoc Tukey’s test.Results: In the cervical region, only the samples from group 2 presented maladaptation (12.5 ± 7.0 µm). In the abutment area, the samples from groups 1 (159.6 ± 6.2 µm) and 2 (149.9 ± 9.1 µm) were statistically similar. In the screw area and the abutment and screw area, group 1 had a larger contact surface compared to group 2 but they were statistically similar.Conclusion: The samples from groups 1 and 3 did not present micro-spaces in the cervical third. Nevertheless, the samples from group 2 presented a mismatch in this region but within the acceptable limits found in the literature.
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Li, Yao Ming, and Jin Ping Qiao. "Connection Force Determination between Crop Roots and Soil." Advanced Materials Research 971-973 (June 2014): 2080–83. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.2080.
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A method of determining the connection force between crop roots and soil was developed. A TG-1 tensile testing device was designed which consisted of an activities tripod platform, a screw mechanism, a special clamp and sensor-signal processing system. The force transferred to the screw mechanism with the help of a hand wheel was only 1/97 of the maximum connection force between crop roots and soil. The clamp used self-locking structure, and it could clamp most of the crop stalks with different diameters. Take the maximum connection force as the measurand for the connection force between crop roots and soil. Using the TG-1 tensile testing device, experiments were carried out on oilseed rape. The results showed connection force between oilseed rape roots and soil ranged from 36N to 237N. The proportion of the force between 100 and 150N was the most, taking up 45.5%.
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Girhammar, Ulf Arne, and Bo Källsner. "Tests and Analyses of Slotted-In Steel-Plate Connections in Composite Timber Shear Wall Panels." Advances in Civil Engineering 2017 (2017): 1–20. http://dx.doi.org/10.1155/2017/7259014.
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The authors present an experimental and analytical study of slotted-in connections for joining walls in the Masonite flexible building (MFB) system. These connections are used for splicing wall elements and for tying down uplifting forces and resisting horizontal shear forces in stabilizing walls. The connection plates are inserted in a perimeter slot in the PlyBoard™ panel (a composite laminated wood panel) and fixed mechanically with screw fasteners. The load-bearing capacity of the slotted-in connection is determined experimentally and derived analytically for different failure modes. The test results show ductile postpeak load-slip characteristics, indicating that a plastic design method can be applied to calculate the horizontal load-bearing capacity of this type of shear walls.
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Han, Fang, Jinwei Jiang, Kai Xu, and Ning Wang. "Damage Detection of Common Timber Connections Using Piezoceramic Transducers and Active Sensing." Sensors 19, no. 11 (May 31, 2019): 2486. http://dx.doi.org/10.3390/s19112486.
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Timber structures have been widely used due to their low-cost and environmental-friendly properties. It is essential to monitor connection damage to ensure the stability and safety of entire timber structures since timber connection damage may induce catastrophic incidents if not detected in a timely manner. However, the current investigations on timber connections focus on mechanical properties and failure modes, and the damage detection of timber connection receives rare attention. Therefore, in this paper, we investigate the damage detection of four common timber connections (i.e., the screw connection, the bolt connection, the decussation connection, and the tooth plate connection) by using the active sensing method. The active sensing method was implemented by using a pair of lead zirconate titanate (PZT) transducers: one PZT patch is used as an actuator to generate stress waves, and the other works as a sensor to detect stress waves after propagating across the timber connection. Based on the wavelet packet energy analysis, the signal energy levels of received stress waves under different damage extent are quantified. Finally, by comparing the signal energy between the intact status and the damage status of the timber connection, we find that the energy attenuates with increasing severity of the connection damage. The experimental results demonstrate that the active sensing method can realize real-time monitoring of timber connection damage, which can guide further investigations.
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Lee, Yeong Huei, Cher Siang Tan, Shahrin Mohammad, Mahmood Md Tahir, and Poi Ngian Shek. "Review on Cold-Formed Steel Connections." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/951216.
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The concept of cold-formed light steel framing construction has been widespread after understanding its structural characteristics with massive research works over the years. Connection serves as one of the important elements for light steel framing in order to achieve its structural stability. Compared to hot-rolled steel sections, cold-formed steel connections perform dissimilarity due to the thin-walled behaviour. This paper aims to review current researches on cold-formed steel connections, particularly for screw connections, storage rack connections, welded connections, and bolted connections. The performance of these connections in the design of cold-formed steel structures is discussed.
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Jeng, Ming-Dih, Po-Yi Liu, Jia-Hum Kuo, and Chun-Li Lin. "Load Fatigue Performance Evaluation on Two Internal Tapered Abutment–Implant Connection Implants Under Different Screw Tightening Torques." Journal of Oral Implantology 43, no. 2 (April 1, 2017): 107–13. http://dx.doi.org/10.1563/aaid-joi-d-16-00129.
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This study evaluates the load fatigue performance of different abutment–implant connection implant types—retaining-screw (RS) and taper integrated screwed-in (TIS) types under 3 applied torque levels based on the screw elastic limit. Three torque levels—the recommended torque (25 Ncm), 10% less, and 10% more than the ratio of recommended torque to screw elastic limits of different implants were applied to the implants to perform static and dynamic testing according to the ISO 14801 method. Removal torque loss was calculated for each group after the endurance limitation was reached (passed 5 × 106 cycles) in the fatigue test. The static fracture resistance results showed that the fracture resistance in the TIS-type implant significantly increased (P < .05) when the abutment screw was inserted tightly. The dynamic testing results showed that the endurance limitations for the RS-type implant were 229 N, 197 N, and 224 N and those for the TIS-type implant were 322 N, 364 N, and 376 N when the screw insertion torques were applied from low to high. The corresponding significant (P < .05) removal torque losses for the TIS-type implant were 13.2%, 5.3%, and 2.6% but no significant difference was found for the RS-type implant. This study concluded that the static fracture resistance and dynamic endurance limitation of the TIS-type implant (1-piece solid abutment) increased when torque was applied more tightly on the screw. Less torque loss was also found when increasing the screw insertion torque.
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LaBelle, James C., J. Randolph Kissell, and Tanya A. Dolby. "Pull-Out Strength of Screws in Screw Chases: Part 1." Key Engineering Materials 710 (September 2016): 115–20. http://dx.doi.org/10.4028/www.scientific.net/kem.710.115.
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This paper presents test results and a proposed pull-out strength equation for tension-loaded screws installed in chases in extruded aluminum profiles. The screws are perpendicular to the extrusion's length. This connection is commonly used to resist outward wind load on glass in curtain walls and skylights. Two types of chase, each with 1/4 in. (6.35 mm) diameter 300 series stainless steel screws were used: a flat chase with AB tapping screws (1/4-14; 14 threads per 25.4 mm) and F tapping screws (1/4-20; 20 threads per 25.4 mm), and a longitudinally ribbed chase with UNC-thread machine screws (1/4-20). The extrusions included six cross-section shapes (three with flat chases and three with ribbed chases) and three alloy-tempers. Pull-out tests of 150 single screws were conducted. The Aluminum Design Manual [1] does not include pull-out strength equations for screws in chases; this research was intended to develop such equations. Pull-out strength increased with an increase in engaged length of screw threads with the chase. The shape and dimensions of the chase also affected the pull-out strength.
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Kalinowski, M., and M. Szczepanik. "Determination of the load factor between screw and flange in screw connection realized with C-rail." IOP Conference Series: Materials Science and Engineering 564 (October 30, 2019): 012065. http://dx.doi.org/10.1088/1757-899x/564/1/012065.
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Michalakis, Konstantinos X., Pasquale (Lino) Calvani, Sinan Muftu, Argiris Pissiotis, and Hiroshi Hirayama. "The Effect of Different Implant-Abutment Connections on Screw Joint Stability." Journal of Oral Implantology 40, no. 2 (April 1, 2014): 146–52. http://dx.doi.org/10.1563/aaid-joi-d-11-00032.
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Dental implants with an internal connection have been designed to establish a better stress distribution when lateral external forces act on the prosthesis and minimize the forces transmitted to the fastening screw. In the present study, 10 externally and 10 internally hexed implants were tested with a compressive force applied with an Instron Universal machine. Four cycles of loading-unloading were applied to each specimen to achieve displacements of 0.5, 1, 2, and 2.5 mm. The mean loads for the first cycle were 256.70 N for the external connection and 256 N for the internal connection implants. The independent t test did not reveal any significant differences among the 2 tested groups (P = .780). For the second cycle, the mean loads needed for a displacement of 1 mm were 818.19 N and 780.20 N for the external connection and the internal connection implants, respectively. The independent t test revealed significant differences among the 2 tested groups (P < .001). In the third cycle, the mean load values for a 2-mm displacement were 1394.10 N and 1225.00 N. The independent t test revealed significant differences among the 2 tested groups (P < .001). The mean loads for the fourth cycle were 1488.00 N for the external connection and 1029.00 N for the internal connection implants. These loads were required for a displacement of 2.5 mm. The independent t test revealed significant differences among the 2 tested groups (P < .001). The results of this in vitro study suggest that the internal connection design of the examined implant system could not prevent screw loosening during overloading. No implant or prosthesis failure was noticed in either group.
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Sahin, Cem, and Simel Ayyildiz. "Correlation between microleakage and screw loosening at implant-abutment connection." Journal of Advanced Prosthodontics 6, no. 1 (2014): 35. http://dx.doi.org/10.4047/jap.2014.6.1.35.
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