Journal articles: 'Double-lap shear test'

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Reinikainen, T., M. Poech, M. Krumm, and J. Kivilahti. "A Finite-Element and Experimental Analysis of Stress Distribution in Various Shear Tests for Solder Joints." Journal of Electronic Packaging 120, no. 1 (March 1, 1998): 106–13. http://dx.doi.org/10.1115/1.2792277.

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Solder alloys are commonly tested with shear tests to study their mechanical properties or low-cycle fatigue performance. In this work, the suitability of various shear tests for quantitative solder-joint testing is investigated by means of the finite element method. The stress state and stress distribution in the following well known geometries are studied: the double-lap test, the ring and plug test, the losipescu test, and two single-lap tests. A new test geometry, the grooved-lap test, is introduced and compared to the conventional tests. The results of simulations with an elastic material model in plane-strain indicate that considerable differences in the purity of the state of shear (rε = −ε1/ε3) as well as in the stress distribution in the joint exist among the shear tests. However, simulations with a nonlinear material model show that stress inhomogenities are smoothed by the plastic and creep deformation occurring in the joint. Optical measurements of the deformation of real single-lap and grooved-lap joints show that the single-lap joint rotates slightly during creep, whereas in the grooved-lap joint no rotation can be detected. This confirms the simulation results that in the single-lap test the initially nonuniform stress distribution changes during creep, and in the grooved-lap test the uniform stress distribution remains constant through the test.

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Liu, Sui, Zhi Dong Guan, Xia Guo, Dong Xiu Yan, Ping Chen, and Jia Liu. "Study on Tensile Strength of Composite Double-Lap Joint." Applied Mechanics and Materials 157-158 (February 2012): 1519–26. http://dx.doi.org/10.4028/www.scientific.net/amm.157-158.1519.

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An experimental and analytical study on ultimate tensile strength of composite double-lap joints with different adhesive thicknesses is employed in the paper，test results indicate the major failure mode of joints is adhesive shear failure and the ultimate strength of joints increasing with thicker adhesive. Analytical model is developed to investigate the adhesive failure of double-lap joint based on the experiments. The model takes into account anisotropy of each ply in the composite laminates and elastic-perfectly plastic behavior of the adhesive in the joints. The validity of analytical model for calculating shear strain/stress distribution is certified by comparing with finite model results. Maximum shear strain criterion is adopted in the analytical model to predict the ultimate tensile load of double-lap joint. Good agreement of the analytical predictions with the experimental results is obtained.

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Falope, F. O., L. Lanzoni, and A. M. Tarantino. "Double lap shear test on steel fabric reinforced cementitious matrix (SFRCM)." Composite Structures 201 (October 2018): 503–13. http://dx.doi.org/10.1016/j.compstruct.2018.06.001.

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Centelles, Xavier, J. Ramon Castro, and Luisa F. Cabeza. "Double-lap shear test on laminated glass specimens under diverse ageing conditions." Construction and Building Materials 249 (July 2020): 118784. http://dx.doi.org/10.1016/j.conbuildmat.2020.118784.

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Zhang, Peng Bo, Zhi Xiang Yu, Yu Ping Sun, and Shi Chun Zhao. "Effect of Lap Gap on the Frictional Performance of Shear-Type Friction Damper." Advanced Materials Research 374-377 (October 2011): 2513–19. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.2513.

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The shear-type friction damper using aluminum alloy as the friction material were designed and tested under cyclical loading to investigate the effect of the lap gap to the frictional performance. The test results indicated that the dampers with a lap gap could also absorb energy stably with the same hysteretic behavior as a general friction damper; the frictional force of the shear-type friction damper depended not only upon the bolts tension by the high-strength bolts that clamped the sliding steel plate but also strongly upon the scale of lap gap. The lap gap changed in a scale of 0.12mm only, the average sliding force has four times increase at a lower level of bolt tension, and a double effect to increasing sliding force at the higher level of bolt tension.

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Sadowski, T., and P. Golewski. "Numerical Study of the Prestressed Connectors and Their Distribution on the Strength of a Single Lap, a Double Lap and Hybrid Joints Subjected to Uniaxial Tensile Test." Archives of Metallurgy and Materials 58, no. 2 (June 1, 2013): 579–85. http://dx.doi.org/10.2478/amm-2013-0041.

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Prestressed joints are widely used in construction using connectors in the form of screws, whose task is to strong clamping of joined parts, thereby the internal forces in joint are transferred by surface friction contact of the elements. In the automotive and aerospace industries hybrid joints are more widely applied. Mechanical connectors are added to the adhesive joint in form of rivets, screws or clinch increasing its strength properties. The aim of this study was to determine how the prestressed connectors influence the mechanical response of hybrid, single and double lap joints. The influence of different distribution of the connectors was also investigated. Numerical study was conducted in ABAQUS program. Mechanical connectors were modeled by using fasteners, that allowed for a considerable simplification of the numerical model. In their application, there is no need for an additional submodels for connectors in the form of the rivet or the bolt. Prestressing is activated by direct application of the force to the connector. In the numerical examples the authors assumed that the diameter of the mechanical connectors was equal to 6mm and shear strength was equal 1kN. Adhesive layers were modeled by using cohesive elements for which maximum shear stresses and fracture energy were specified. The layer thickness was assumed to be equal 0.1mm and it was initially removed from the areas where mechanical connectors were placed. Two types of joints were analysed in the study: the single lap joint with lap dimensions 40x40mm as well as the double lap joint with lap dimensions 40x20mm, from which it results that theoretical strength of both connections should be the same. The prestressing of connectors was introduced by the force 1.5kN. For all pure - mechanical joints and for single lap joints positive effects were obtained. For double lap joints additional prestressing did not significantly affect for their strength. The influence of distribution of mechanical connectors was additionally analyzed by consideration of three configurations, where the rows of rivets were located at distances of 5, 10 and 15mm from the lap edge. The maximum increase of the load capacity by 24% was achieved for single lap joint as well as 35.7% for double lap joint. The obtained numerical results indicate the positive effects of additional pressure and allows for practical suggestions how to correct and optimize spacing distance of mechanical connectors in hybrid joints to get better mechanical response.

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IWASA, Masaaki, and Toshio HATTORI. "Fracture Behavior of GFRP/Stainless Steel Double Lap Adhesive Joints on Tensile Shear Test." Proceedings of the 1992 Annual Meeting of JSME/MMD 2002 (2002): 477–78. http://dx.doi.org/10.1299/jsmezairiki.2002.0_477.

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Rameshni, Ramin, Stefano Arcovio, Mark Green, and Colin MacDougall. "Experimental and numerical study of adhesively bonded glass fibre-reinforced polymer – to-steel double-shear lap splices." Canadian Journal of Civil Engineering 40, no. 11 (November 2013): 1140–49. http://dx.doi.org/10.1139/cjce-2012-0508.

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This study investigates, experimentally and using finite element analysis, the adhesive bond between glass fibre-reinforced polymer (GFRP) and steel. Seventeen double-shear lap-splice were fabricated and tested in tension. The results show that the methacrylate adhesive used had higher bond strengths than the epoxy adhesive. A finite element model for selected test specimens was developed to analyze the stress within the adhesive. The model was verified by comparison with strain data from the shear lap-splice tests. The model was used to determine the maximum principal stress in the epoxy adhesive and the maximum shear strain in the methacrylate adhesive at failure, and thus quantify the characteristic strength of these adhesives. It was shown that the ductility of the methacrylate adhesive allowed it to yield at locations of stress concentrations, providing higher splice capacity, despite having a lower nominal shear strength as compared with the epoxy adhesive.

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Serizawa, Hisashi, Charles Lewinsohn, Mrityunjay Singh, and Hidekazu Murakawa. "Numerical Analysis of Test Methods for Evaluating Shear Strength of Ceramic Composite Joints Using Interface Element." Materials Science Forum 539-543 (March 2007): 2143–48. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.2143.

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As examples of the most typical methods to determine the shear strength of SiC/SiC composite joints, the asymmetrical four point bending test of butt joined composite, the tensile test of lap joined composite and the compressive test of double-notched composite joint were analyzed by using finite element method with the interface element. From the calculation results, it was found that the shear strength in the asymmetrical bending test was controlled by both the surface energy and the shear strength at the interface regardless of their combination although the strength in the tensile test or the compressive test was governed by the surface energy when the shear strength was large. Also, it was revealed that the apparent shear strength of the composite joint obtained experimentally might be affected by the combination of the surface energy and the shear strength at the interface.

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Serizawa, Hisashi, and Hidekazu Murakawa. "A Critical Review on Modeling of Fracture Behavior of Ceramic Joints." Advances in Science and Technology 88 (October 2014): 121–30. http://dx.doi.org/10.4028/www.scientific.net/ast.88.121.

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As examples of the most typical methods to determine the shear strength of SiC/SiC composite joints, the asymmetrical four point bending test of a butt-joined composite, the tensile test of a lap-joined composite, and the compression test of a double-notched composite joint were analyzed by using a finite element method with the interface element. From the results, it was found that the shear strength in the asymmetrical bending test was controlled by both the surface energy and the shear strength at the interface regardless of their combination while the strength in the tensile test or the compression test was governed by the surface energy when both the surface energy and the shear strength were large. In addition, the interface element was employed in order to examine the influence of the specimen geometry on the microstructural fracture morphology in nanoSiC/SiC composite during a miniaturized Double Notch Shear (DNS) test. From the serial computations, it is revealed that a relationship between the inter-laminar shear strength and the yield stress seems to be very important for selecting appropriate specimen geometry of the miniaturized DNS test.

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Mohan, J., A. Karač, Neal Murphy, and Alojz Ivanković. "An Experimental and Numerical Investigation of the Mixed-Mode Fracture Toughness and Lap Shear Strength of Aerospace Grade Composite Joints." Key Engineering Materials 488-489 (September 2011): 549–52. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.549.

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In the present study, the mixed-mode fracture toughness of an adhesively bonded composite joint system was examined using a variety of linear elastic fracture mechanics (LEFM) based tests. These tests include the mode I double cantilever beam (DCB), mixed-mode asymmetrical DCB (ADCB) and mode II end load split (ELS) test. The joint system was also evaluated using the wide area lap shear (WALS) test that is often employed by the aerospace industry. While lap shear type tests are relatively simple to perform and post-process compared to their LEFM counterparts, the results can often be misleading and are greatly dependent on the overlap length, thickness of substrate and type of fillet. The experimental tests were also simulated using OpenFOAM, a finite volume based software package. Through this combined experimental-numerical approach, a greater understanding of the influence of the peel ply surface treatment and scrim cloth on the behaviour of the WALS test was achieved.

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Subramanian, Sankara J., and Vijay K. R. Penmetcha. "Strain Evolution during Lap Shear Testing of SnCu Solder." Applied Mechanics and Materials 70 (August 2011): 303–8. http://dx.doi.org/10.4028/www.scientific.net/amm.70.303.

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The lap-shear test is frequently used in the microelectronics industry to obtain mechanical properties of solder joints. In these tests, solder joints formed between slender metallic substrates are pulled apart in a simple shear configuration. Although it is known that calculation of stress-strain curves from lap shear tests is not straightforward due to rotation of the joints and strain inhomogeneity within the joint, these tests still find widespread use due to their simplicity and apparent ease of use. Chawla and co-workers [1, 2] show that the state of strain near the solder-substrate interfaces is significantly different from that in the interior of the joint and that this effect is only minimized for large joints. In the present work, we offer experimental evidence for these conclusions by presenting full-field strain measurements on solder joints in double-lap shear configuration, obtained using Digital Image Correlation (DIC). While confirming that significant strain gradients exist within the joint, the present work also indicates that a simple calculation of shear strain as axial displacement of the joint divided by joint thickness is misleading due to the presence of a significant gradient of the transverse displacement along the loading direction. This gradient persists through the course of the deformation and results in the actual average shear strain in the joint being smaller than that computed from the axial displacement alone.

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Machalická, Klara, P. Pokorný, and M. Vokáč. "Influence of the adhesive type and metal substrate on adhesion of bonded joints after salt spray test." Koroze a ochrana materialu 62, no. 2 (May 1, 2018): 54–64. http://dx.doi.org/10.1515/kom-2018-0006.

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Abstract This article was focused on the evaluation of neutral salt spray test effect (according to ISO 9124), procedure E4, on mechanical properties of load-bearing adhesive joints. The study also comprises the influence of substrate material (mild steel, aluminum alloys) and substrate surface roughness (verified by optical confocal microscopy). The experimental program contained acrylate-based adhesive and hybrid silicone polyurethane based adhesive which were applied in double lap joints loaded by shear.

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Li, Gui Bing, Ai Hui Zhang, and Wei Liang Jin. "Experimental Investigation on Effective Bond Length of Flexurally CFRP-Strengthened RC Beams Failed by Intermediate Crack Debonding." Advanced Materials Research 163-167 (December 2010): 977–80. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.977.

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The models to calculate the effective bond length determined by single-lap or double-lap shear tests are more suitable for the end-debonding failure; and the improved models based on the simply shear test models to calculate the effective bond length of flexural CFRP-strengthened beams failed by intermediate crack debonding (IC debonding) are also lack of the support of experimental data. To investigate the effective bond length of flexural CFRP-strengthened beams, a total of 9 flexurally CFRP-strengthened beams were tested. The experimental results show that the existing models are very conservative for calculating the effective bond length in flexural FRP-strengthened RC beams failed by IC debonding. Based on the experimental results, this paper presents a model to calculate the effective bond length of flexural FRP-strengthened RC beams failed by IC debonding, and a model to calculate the plastic hinge length at the shear-flexure span.

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Calabrese, Angelo Savio, Pierluigi Colombi, and Tommaso D'Antino. "A Bending Test Set-Up for the Investigation of the Bond Properties of FRCM Strengthenings Applied to Masonry Substrates." Key Engineering Materials 817 (August 2019): 149–57. http://dx.doi.org/10.4028/www.scientific.net/kem.817.149.

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Existing masonry and reinforced concrete structures are characterized by a wide use of structural and non-structural masonry members such as structural walls, infill walls, arches, vaults etc. All these members are characterized by high vulnerability when subjected to seismic events, since unreinforced masonry has a negligible tensile strength. The use of fiber reinforced polymers (FRP) composites has become a common practice and it represents a light-weight, easy, fast, and non-invasive solution for rehabilitation of existing masonry structures. Fabric reinforced cementitious matrix (FRCM) are relatively newly developed composite materials, representing a valid alternative to FRP in strengthening and retrofitting of existing reinforced concrete and masonry structures. Despite of the numerous advantages guaranteed by the inorganic matrix, the bond-behavior between the fibers and the embedding matrix is still under investigation. Different set-ups have been proposed in the literature to study the bond behavior of FRCM composites. Among them, single-and double-lap shear tests are the most commonly used. In this paper, the bond behavior of a polyparaphenylene benzobisoxazole (PBO) FRCM composite applied to masonry elements is studied using a bending and a single-lap shear test set-up. The bond capacities obtained by the two set-ups are analyzed and discussed.

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Yarra, Siddaiah, Faramarz Gordaninejad, Majid Behrooz, Gokhan Pekcan, Ahmad M. Itani, and Nelson Publicover. "Performance of a large-scale magnetorheological elastomer–based vibration isolator for highway bridges." Journal of Intelligent Material Systems and Structures 29, no. 20 (September 12, 2018): 3890–901. http://dx.doi.org/10.1177/1045389x18799493.

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This study presents an experimental investigation on the magnetorheological effect of a new magnetorheological elastomer–based adaptive bridge isolation bearing system. Two identical magnetorheological elastomer–based adaptive bridge bearings (isolators) were designed and fabricated. Electromagnets were incorporated to create a closed-loop magnetic path in the magnetorheological elastomer layers. A double-lap shear and compression test setup was utilized to characterize the mechanical properties of the system subjected to scaled structural cyclic forces and strains. Experimental results demonstrated that the effective stiffness of adaptive bridge bearings increases with increased applied magnetic field and a compressive force resulted in larger apparent shear stiffness. Also, increasing loading frequency resulted in larger apparent shear stiffness and lower magnetorheological effect and similarly, however, a compressive force resulted in smaller magnetorheological effects.

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Gong, Yongzhi, Yingjie Shan, Yuyuan Wu, Liping Wang, Xiaojie Liu, and Faxing Ding. "Bond Properties of Carbon Fiber Reinforced Polymer and Corrosion-Cracked Reinforced Concrete Interface: Experimental Test and Nonlinear Degenerate Interface Law." Materials 14, no. 18 (September 15, 2021): 5333. http://dx.doi.org/10.3390/ma14185333.

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Existing experimental research on bond properties of the interface between Carbon Fiber Reinforced Polymer (CFRP) and damaged concrete is limited, although CFRP strengthening technology has been widely used for corroded reinforced concrete structures. This work investigated the bond behavior of CFRP to the corrosion-cracked concrete interface, in which three factors were considered for experimentation, including corrosion degree, concrete strength and concrete cover thickness. The tests were conducted by developing a self-balancing double shear lap test device. In addition, a corrosion scene was provided simultaneously to simulate the external corrosion environment. The results showed that three peeling modes of CFRP sheets were observed with respect to corrosion degrees of the steel bars. The effects of the three factors on the stripping bearing capacity and effective bond length of CFRP sheets were discussed by systematic parametric analysis. Finally, a nonlinear degenerate law of CFRP-to-concrete interface considering the corrosion degree was improved and verified in this study.

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Babaee, Saeed, Zahra Monjezi, and Milad Saadat Tagharoodi. "Statistical Taguchi Optimization for Preparation and Adhesion Evaluation of Epoxy Insulator to the Surface of Double Base Propellant Grain." Journal of New Developments in Chemistry 2, no. 1 (December 8, 2018): 38–47. http://dx.doi.org/10.14302/issn.2377-2549.jndc-18-2479.

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In this work, Taguchi design (orthogonal array, OA9) was used for the adhesion investigation of an epoxy insulator to a double base (DB) propellant grain. In this manner three epoxy resins based on diglycidylether bisphenol A (DGEBA) and three polyamine curing agents with an active diluent based on DGEBA were used. Therefore, the effects of resin type, curing agent type with its amount and diluent quantity as main factors were investigated on the single lap shear strength (adhesion strength) and then the results were quantitatively evaluated by the analysis of variance (ANOVA). The data given of ANOVA predicted that the best adhesion strength of 15.584 ± 1.606 MPa was obtained for the optimum conditions of MANA POX-102 as epoxy resin, H-37 as curing agent with 57 phr, ERYSYS GE-30 as diluent with 5 phr. In comparison, practical result of adhesion strength obtained for the optimum conditions was 15.4 ± 0.2 MPa. Also the Pull-off test results on the surface of the DB propellant showed that the maximum adhesion strength (related to the optimal conditions) is 2.64 ± 0.2 MPa.

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Guilpin, Franciere, Barton, Blacklock, and Birkett. "A Numerical and Experimental Study of Adhesively-Bonded Polyethylene Pipelines." Polymers 11, no. 9 (September 19, 2019): 1531. http://dx.doi.org/10.3390/polym11091531.

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Adhesive bonding of polyethylene gas pipelines is receiving increasing attention as a replacement for traditional electrofusion welding due to its potential to produce rapid and low-cost joints with structural integrity and pressure tight sealing. In this paper a mode-dependent cohesive zone model for the simulation of adhesively bonded medium density polyethylene (MDPE) pipeline joints is directly determined by following three consecutive steps. Firstly, the bulk stress–strain response of the MDPE adherend was obtained via tensile testing to provide a multi-linear numerical approximation to simulate the plastic deformation of the material. Secondly, the mechanical responses of double cantilever beam and end-notched flexure test specimens were utilised for the direct extraction of the energy release rate and cohesive strength of the adhesive in failure mode I and II. Finally, these material properties were used as inputs to develop a finite element model using a cohesive zone model with triangular shape traction separation law. The developed model was successfully validated against experimental tensile lap-shear test results and was able to accurately predict the strength of adhesively-bonded MPDE pipeline joints with a maximum variation of <3%.

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Stapleton, Seth E., Cole C. McDaniel, William F. Cofer, and David I. McLean. "Performance of Lightly Confined Reinforced Concrete Columns in Long-Duration Subduction Zone Earthquakes." Transportation Research Record: Journal of the Transportation Research Board 1928, no. 1 (January 2005): 184–92. http://dx.doi.org/10.1177/0361198105192800120.

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The main goals of this research were to evaluate typical 1950s and 1960s as-built bridge columns in western Washington State in large subduction zone earthquakes and to investigate the dependency of failure mechanisms on loading history. Eight displacement histories were applied to eight nominally identical, half-scale, circular reinforced concrete columns expected to respond primarily in flexure (flexure-dominated). The main design deficiencies were a short longitudinal reinforcement lap splice at the base of the column (35 db) and inadequate transverse reinforcement. Test results showed that the failure mode of reinforced concrete columns was controlled by the column loading history. Three distinct failure mechanisms were observed for columns with an aspect ratio of approximately 4.2, assuming symmetric, double-curvature behavior. Large initial displacements greater than six times the effective yield displacement (Δ y) were likely to result in shear failures. Columns experiencing many displacements less than 4Δ y were likely to fail because of longitudinal reinforcement buckling. Columns subjected to several displacement excursions less than 4Δ y followed by an excursion greater than 6Δ y were likely to fail by longitudinal reinforcement slipping within the splice region. Despite the deficiencies present in circular reinforced concrete bridge columns built before 1975 in western Washington State, this study showed that flexure-dominated columns with a 35 db lap splice in multiple-column bent, three-or four-span bridges were not likely to experience significant damage in the predicted Cascadia Subduction Zone earthquake. However, other components of the bridge need to be assessed to determine whether the global bridge response is acceptable under the predicted Cascadia Subduction Zone earthquake.

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Rivero, Pedro J., Rafael J. Rodriguez, Silvia Larumbe, María Monteserín, Francisco Martín, Amador García, Carolina Acosta, et al. "Evaluation of Functionalized Coatings for the Prevention of Ice Accretion by Using Icing Wind Tunnel Tests." Coatings 10, no. 7 (June 30, 2020): 636. http://dx.doi.org/10.3390/coatings10070636.

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Ice accretion presents serious safety issues, as airplanes are exposed to supercooled water droplets both on the ground and while flying through clouds in the troposphere. Prevention of icing is a main concern for both developers and users of aircraft. The successful solution of this problem implies the combination of active and passive methods and the use of advanced sensors for early detection of icing and monitoring of ice accretion and de-icing processes. This paper focuses on the development of passive solutions. These include advanced anti-icing coatings deposited by a variety of chemical methods including sol-gel, advanced paints based on polyester combined with fluorinated derivatives and applied by electrostatic spray deposition and conventional silicone-based paints modified by adding alumina nanoparticles. Water contact angle has been measured in all cases, demonstrating the hydrophobic character of the coatings. An ice accretion test has been carried out in a laboratory scale icing wind tunnel (IWT) located in a cold climate chamber. Three different studies have been undertaken: ice accretion measurement, durability of the anti-icing behavior after several icing/de-icing cycles and ice adhesion testing by means of the double lap shear test (DLST) methodology. All the studied coatings have shown significant anti-icing behavior which has been maintained, in some cases, beyond 25 cycles. Although these results are still far from any possible application for aeronautic components, they provide interesting insights for new developments and validate the laboratory scale tests.

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Mora, J., P. García, R. Muelas, and A. Agüero. "Hard Quasicrystalline Coatings Deposited by HVOF Thermal Spray to Reduce Ice Accretion in Aero-Structures Components." Coatings 10, no. 3 (March 20, 2020): 290. http://dx.doi.org/10.3390/coatings10030290.

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Weather hazards, in particular icing conditions, are an important contributing factor in aviation accidents and incidents worldwide. Many different anti-icing strategies are currently being explored to find suitable long-lasting solutions, such as surface engineering, which can contribute to reduce ice accumulation. Quasicrystals (QCs) are metallic materials, but with similar properties to those of ceramic materials, such as low thermal and electrical conductivities, and high hardness. In particular, QCs that have low surface energy are commercially used as coatings to replace polytetrafluoroethylene (PTFE), also known as Teflon, on frying pans, as they do not scratch easily. PTFE exhibits excellent anti-wetting and anti-icing properties and therefore QCs appear as good candidates to be employed as ice-phobic coatings. Al-based QCs have been applied by High Velocity Oxyfuel (HVOF) thermal spray on typically used aeronautic materials, such as Ti and Al alloys, as well as steels. The coatings have been characterized and evaluated, including the measurement of hardness, roughness, wetting properties, ice accretion behavior in an icing wind tunnel (IWT), and ice adhesion by a double lap shear test. The coatings were studied, both as-deposited, as well as after grinding, in order to study the effect of the surface roughness and morphology on the ice accretion and adhesion properties. The QC coating was compared with PTFE and two polyurethane (PU)-based commercial paints, one of them known to have anti-icing properties, and the results indicate an ice accretion reduction relative to these two materials, and ice adhesion lower than bare AA6061-T6, or the PU paint in the ground version of one of the two QCs. Since the QC coatings are hard (GPa Vickers hardness > 5), a durable behavior is expected.

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Asada, Yoshihiro, Isamu Yoshitake, Atsushi Ogawa, and Yuji Fujimoto. "BOND STRENGTH OF STEEL-CONCRETE COMPOSITE ELEMENTS USING A CEMENTITIOUS ADHESIVE." Proceedings of International Structural Engineering and Construction 1, no. 1 (November 2014). http://dx.doi.org/10.14455/isec.res.2014.115.

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Steel-concrete composite slabs have been used for bridge deck construction in Japan because of several advantages, e.g., safety construction and high fatigue durability. On the other hand, these slabs may cause negative influences such as overweight, increasing costs and low constructability, due to many mechanical shear connectors. The quantities of shear connectors may be reduced by gluing steel-plate and concrete with a cementitious adhesive. The present study aims at examining shear bond strength and quantifying the dispersion of the strength. To investigate the dispersion, a double-lap shear test is conducted, in addition to a simple direct shear test, to examine surface treatment. A Monte Carlo Simulation using the Weibull distribution of the strength is performed to evaluate the effect of dispersion. The simulation implies that the shear stress due to the traffic load may be negligible, indicating the applicability of the composite system for highway bridge decks.

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Abazadeh, B., and HR Maleki. "Effect of bolt tightening on the fatigue behavior of GLARE double shear lap joints." Journal of Composite Materials, March 15, 2021, 002199832110033. http://dx.doi.org/10.1177/00219983211003315.

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In this paper, the effect of bolt torque tightening has been investigated on the fatigue behavior of GLARE in double shear lap configuration. To do so, experimental fatigue tests were conducted using GLARE3-5/4-0.4 specimens with applied torques of 0 (finger tightened), 2 and 4 Nm at different cyclic longitudinal load ranges to achieve the stress-life (S-N) curves. The results revealed that applying and increasing the clamping force enhances the fatigue life of the GLARE specimens. Furthermore, comparison of fatigue test results of GLARE and available monolithic aluminum alloy 2024-T3 plates indicated when the applied load range is low, the effect of clamping force is more noticeable in GLARE specimens due to longer fatigue crack growth life of GLARE. Also, the occurrence of fretting fatigue didn’t reduce the fatigue life of GLARE specimens considerably in contrary to aluminum sheets because of the laminated structure of GLARE. The obtained results can provide insights in designing bolted GLARE joints with superior fatigue in-service performance.

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Haryanto, Yanuar, Hsuan-Teh Hu, Ay Lie Han, Fu-Pei Hsiao, Charng-Jen Teng, Banu Ardi Hidayat, and Laurencius Nugroho. "Nonlinear 3D Model of Double Shear Lap Tests for the Bond of Near-surface Mounted FRP Rods in Concrete Considering Different Embedment Depth." Periodica Polytechnica Civil Engineering, April 6, 2021. http://dx.doi.org/10.3311/ppci.17309.

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The utilization of near-surface mounted Fiber Reinforced Polymer (FRP) reinforcement as a method of strengthening in reinforced concrete structures has increased considerably in recent years. Moreover, the application of double-shear lap tests for this rein-forcement method leads to the achievement of a local bond-slip behavior in a bonded joint. This research, therefore, focused on 3-D modeling of this type of test to suitably characterize the bond mechanics between FRP rods and concrete at various embedment depth. The use of different alternatives to represent the interface between the FRP rod and concrete were analyzed after which a comparison was drawn between the numerical finite element (FE) simulations and experimental measurements. The results showed the prediction of the load–slip corresponded with the data obtained from the experiment. Finally, the proposed model has the ability to express the relationship between the penalty stiffness parameters in shear direction Kss = (Ktt) and the embedment depth of FRP rods.

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Pierce, David M., Sheri D. Sheppard, Arlo F. Fossum, Paul T. Vianco, and Mike K. Neilsen. "Development of the Damage State Variable for a Unified Creep Plasticity Damage Constitutive Model of the 95.5Sn–3.9Ag–0.6Cu Lead-Free Solder." Journal of Electronic Packaging 130, no. 1 (January 31, 2008). http://dx.doi.org/10.1115/1.2837513.

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A unified creep plasticity damage (UCPD) constitutive model was developed to predict the fatigue of 95.5Sn–3.9Ag–0.6Cu solder joints. Compression, stress-strain and creep properties were generated in previous studies of this solder. Crack damage was reflected in a single state variable, Dω, in the model. Isothermal fatigue tests were performed at 25°C, 100°C, and 160°C using a double-lap shear test specimen. A new approach to fitting the revised damage model is proposed based on finite element analysis (FEA) simulation of the load decay of the fatigued solder material. Accurate predictions required that those parameters be temperature dependent. The UCPD constitutive model was successfully implemented as a subroutine in the commercial finite element code ANSYS®. Consistent predictions were obtained as demonstrated by a comparison of results generated from FEA simulation of the test assembly against analogous experimental results.

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Pierce, David M., Sheri D. Sheppard, and Paul T. Vianco. "A General Methodology to Predict Fatigue Life in Lead-Free Solder Alloy Interconnects." Journal of Electronic Packaging 131, no. 1 (February 13, 2009). http://dx.doi.org/10.1115/1.3068313.

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The ubiquitous eutectic tin-lead (Sn–Pb) solder alloys are soon to be replaced with lead-free alternatives. In light of this transition, new computational tools for predicting the fatigue life of lead-free solders are required. A fatigue life prediction methodology was developed, based on stress-strain, creep, and isothermal fatigue data; the latter generated using a double lap-shear (DLS) test assembly. The proposed fatigue life prediction methodology builds on current practices in fatigue prediction for solder alloys, particularly the concepts of unpartitioned energy methods in finite element analysis (FEA) and continuum damage mechanics. As such, the current state of these fields is briefly discussed. Next, the global and local FEA simulations of the DLS test assembly are detailed. A correlation is then made between the empirical data and the FEA simulations. A general fatigue life prediction methodology is next described in detail. Finally, this methodology is tested and verified against the empirical data.

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Mohammadipour, Amir, and Kaspar Willam. "On Energy Release Rates and Configurational Forces for Interfacial Propagating Cracks: A Lattice Approach With a Brittle Erosion Technique." Journal of Applied Mechanics 84, no. 2 (November 22, 2016). http://dx.doi.org/10.1115/1.4035181.

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A numerical 2D lattice approach with an erosion algorithm is employed to analyze bimaterial interface fracture quantities in brittle heterogeneous materials in the context of linear elastic fracture mechanics (LEFM). The concept of configurational force is elucidated and the importance of nodal configurational changes in a mesh where no stress–strain analyses are needed is investigated. Three fracture problems, i.e., an infinite panel with a bi-material interface crack, a double-lap shear test, and a prenotched four-point bending masonry beam are then considered. Validated by analytical solutions, the lattice model uses two distinct postprocessing approaches to derive the energy release rates and configurational forces directly at bimaterial interface crack tips. While the first method takes advantage of the change of the lattice mesh's global stiffness matrix before and after crack growth without any stress–strain calculations to obtain crack tip driving forces, the second approach analyzes the configurational forces opposing the crack tip motion using the Eshelby stress tensor and local force balance law in cracked and heterogeneous domains. It is demonstrated that the discrete material forces at crack tips are closely equal to the tip driving forces for the three fracture problems, confirming that the lattice is an appropriate numerical tool to analyze fracture properties of evolving interface cracks. Satisfying C1 continuity by including rotational displacements for frame struts, there is also no need for the lattice to update interior computational points in the mesh to eliminate spurious material forces away from the tip.

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Yu, Qiang, Zdeněk P. Bažant, John Bayldon, Jia-Liang Le, Ferhun C. Caner, Wei Heok Ng, Anthony M. Waas, and Isaac M. Daniel. "Scaling of Strength of Metal-Composite Joints—Part I: Experimental Investigation." Journal of Applied Mechanics 77, no. 1 (October 1, 2009). http://dx.doi.org/10.1115/1.3172254.

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Knowledge of the size effect on the strength of hybrid bimaterial joints of steel and fiber composites is important for new designs of large lightweight ships, large fuel-efficient aircrafts, and lightweight crashworthy automobiles. Three series of scaled geometrically similar specimens of symmetric double-lap joints with a rather broad size range (1:12) are manufactured. The specimens are tested to failure under tensile displacement-controlled loading, and at rates that ensure the peak load to be reached within approximately the same time. Two series, in which the laminate is fiberglass G-10/FR4, are tested at Northwestern University, and the third series, in which the laminate consists of NCT 301 carbon fibers, is tested at the University of Michigan. Except for the smallest specimens in test series I, all the specimens fail by propagation of interface fracture initiating at the bimaterial corner. All the specimens fail dynamically right after reaching the maximum load. This observation confirms high brittleness of the interface failure. Thus, it is not surprising that the experiments reveal a marked size effect, which leads to a 52% reduction in nominal interface shear strength. As far as the inevitable scatter permits it to see, the experimentally observed nominal strength values agree with the theoretical size effect derived in Part II of this study, where the size exponent of the theoretical large-size asymptotic power law is found to be −0.459 for series I and II, and −0.486 for series III.

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Journal articles on the topic 'Double-lap shear test'

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