Journal articles on the topic 'Lap joints'
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1
Khalid, Asad A. "Effect of Interface Geometry on Strength of Single Lap Adhesive Joint of Sisal-Glass/Epoxy Laminates." Key Engineering Materials 858 (August 2020): 20–26. http://dx.doi.org/10.4028/www.scientific.net/kem.858.20.
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In this project, experimental work on tensile behaviour of single lap adhesive joints of sisal, glass and hybrid sisal-glass/epoxy composite laminates has been carried out. Composite laminates were fabricated by hand lay-up method using chopped strand mat sisal and glass fibers with epoxy resin matrix. Lab joints of four interface geometries; straight flat, triangular, rectangular and sinusoidal were fabricated. Tensile load-displacement relations were drawn and discussed. Effect of interface geometry and material type on maximum load and strength of the single lap joint was investigated. Failure mechanism of the fractured specimens was discussed. Results show that the glass/epoxy lap joints with semi-circular adhesive interface geometry supported load higher respectively 14.26%, 26.13%, and 30.79% than rectangular, triangular and straight flat interface geometries. Glass/epoxy lap joint with semi-circular interface geometry supported tensile load higher 5.61% and 21.83% than that obtained from hybrid sisal-glass and sisal/ epoxy adhesive joints. While the shear strength was found higher respectively 6.19% and 18.69%. Adhesive failure mode was observed for most of the single lap joints investigated. Mixed failure mode of adhesive and adherend materials was observed on the sisal/epoxy lap joints.
2
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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Lam, Angus C. C., J. J. Roger Cheng, Michael C. H. Yam, and Gaylene D. Kennedy. "Repair of steel structures by bonded carbon fibre reinforced polymer patching: experimental and numerical study of carbon fibre reinforced polymer – steel double-lap joints under tensile loading." Canadian Journal of Civil Engineering 34, no. 12 (December 2007): 1542–53. http://dx.doi.org/10.1139/l07-074.
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The behavior of carbon fibre reinforced polymer (CFRP) composite bonded to a steel plate double-lap joint was investigated experimentally. A total of 19 specimens were tested with the major test parameters being the bonded lap length, LL, and the axial adherend stiffness ratio, ETR. Five of the 19 specimens were prepared using CFRP sheets, and the rest using CFRP plates. Two CFRP plate specimens were prepared with a tapered lap joint, and their results were compared with those of counterpart specimens prepared without tapered lap joints. In general, the behavior of specimens made from either CFRP sheets or CFRP plates were similar. The joint's axial load carrying capacity increased with increasing LL up to a certain limit, when the joint's load carrying capacity could no longer be increased by increasing LL. However, experimental results showed that a larger failure deformation could be achieved by increasing LL past this limit. Specimens that had the same inner adherend thickness but higher axial adherend stiffness ratios showed higher axial load carrying capacities. Test results also showed that the strengths of tapered lap joints were almost the same as those of nontapered lap joints with the same LL. Nonlinear finite element analysis was carried out to study the stress–strain behavior of the adherend and the adhesive of the double-lap joint. Using finite element analysis results in an analytical solution obtained from the literature, predictions of the joint's maximum axial strength and minimum required LL were made. This analytical solution provided good predictions when compared with test results, producing test to predicted ratios from 0.88 to 1.14.
4
Fongsamootr, Thongchai, Charoenyut Dechwayukul, Notsanop Kamnerdtong, Carol A. Rubin, and George T. Hahn. "Parametric Study of Combined Adhesive-Riveted Lap Joints." Key Engineering Materials 261-263 (April 2004): 399–404. http://dx.doi.org/10.4028/www.scientific.net/kem.261-263.399.
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Riveted lap joints are widely used to assemble complex structures, e.g. aircraft fuselages. A thin layer of adhesive (sealant), is normally applied to lap joints in order to restrict the entry of moisture and retard corrosion. In this work, combined adhesive-riveted lap joints were studied to understand the effect of three parameters: panel thickness, adhesive stiffness and adhesive layer thickness, on single row non-countersunk riveted lap joints. Finite element analysis (FEA), along with Thin Adhesive Layer Analysis (TALA-developed for simulating the adhesive layer in lap joint models), were used to analyze the joint behavior. In previous studies, the stress concentration factor for single row riveted lap joints was found to be approximately 6.1, and the stress concentration factor for sealed riveted lap joints was approximately 5.2 for a 180 micron thick sealant layer. In this study, panel thickness, adhesive stiffness and adhesive layer thickness were varied parametrically in FEA analyses to determine their affects on the joints. The FEA/TALA results were used to predict the fatigue life of the joints as functions of the three parameters. The results show that the maximum tensile stress is smaller with a smaller panel thickness. The results also showed that the stress concentration factor in the joints was reduced when the stiffness of the adhesive layer was increased or when the thickness of the adhesive layer was decreased. Finally, fatigue tests showed that the fatigue life of the combined adhesive-riveted lap joints was greater than for riveted lap joints without adhesive.
5
Sanati, M., Y. Alammari, J. H. Ko, and S. S. Park. "Identification of joint dynamics in lap joints." Archive of Applied Mechanics 87, no. 1 (September 21, 2016): 99–113. http://dx.doi.org/10.1007/s00419-016-1179-8.
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Vaziri, A., H. Nayeb-Hashemi, and H. R. Hamidzadeh. "Experimental and Analytical Investigations of the Dynamic Response of Adhesively Bonded Single Lap Joints." Journal of Vibration and Acoustics 126, no. 1 (January 1, 2004): 84–91. http://dx.doi.org/10.1115/1.1596550.
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Dynamic response of single lap joints, subjected to a harmonic peeling load is studied theoretically and experimentally. In the theoretical part, dynamic response of a single lap joint clamped at one end and subjected to a harmonic peeling load at the other end is investigated. Adherents are modeled as Euler-Bernouli beams joined in the lap area by a viscoelastic adhesive layer. Both axial and transverse deformations of adherents are considered in deriving the equations of motion. The effects of adhesive layer thickness, mechanical properties and its loss factor on the dynamic response of the joint are investigated. Furthermore, effects of defects such as a void in the lap area on the dynamic response of the joints are studied. The results showed that frequencies where peak amplitudes occurred were little dependent on the adhesive loss factor. However, peak amplitudes reduced for joints with a higher adhesive loss factor. Furthermore, the results indicated that for the joint geometries and properties investigated the system resonant frequencies were not affected by the presence of a central void covering up to 80% of the overlap length. In the experimental part, single lap joints were fabricated using 6061-T6 Aluminum. Adherents were joined together using Hysol EA 9689 adhesive film. Joints with various central voids were manufactured by removing adhesive film from the desired area of lap joints prior to bonding adherents. Dynamic responses of the joints were investigated using the hammer test technique. The system response was measured using both an accelerometer and a noncontact laser vibrometer. The natural frequencies of the joints obtained by using the laser vibrometer were very close to those obtained theoretically. However, natural frequencies obtained by using an accelerometer depended on the accelerometer location in the system, which was attributed to its mass contribution to the over- all system mass. A central void covering less than 80% of the overlap length had little effect on the system resonance frequencies. This was in agreement with the theoretical results. In contrast total system-damping ratios were a function of the void size. Joints without a void exhibited higher damping.
7
Razavi, SMJ, MR Ayatollahi, M. Samari, and LFM da Silva. "Effect of interface non-flatness on the fatigue behavior of adhesively bonded single lap joints." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 7 (November 6, 2017): 1277–86. http://dx.doi.org/10.1177/1464420717739551.
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This paper addresses numerical and experimental examination of the role of zigzag interface shapes on the load bearing capacity and fatigue life of adhesively bonded single lap joints. Aluminum adherends with non-flat zigzag interfaces were tested under both quasi-static and fatigue loading conditions. The quasi-static test results revealed that the non-flat adhesive joints have higher load bearing capacity compared to the conventional flat single lap joints. Comparative fatigue tests with different loading levels revealed that the non-flat zigzag single lap joint had considerably higher fatigue life than the conventional lap joint.
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He, Changshu, Zhiqiang Zhang, Ying Li, Jingxun Wei, Menggang Zhai, Su Zhao, and Xiang Zhao. "Interface Characteristics and Mechanical Properties of Ultrasonic-Assisted Friction Stir Lap Welded 7075-T6 Aluminium Alloy." Materials 13, no. 23 (November 25, 2020): 5335. http://dx.doi.org/10.3390/ma13235335.
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In this work, friction stir lap welding (FSLW) and ultrasonic-assisted friction stir lap welding (UAFSLW) was applied to 6-mm-thick 7075-T6 alloy sheets using three welding tools with the same process parameters. The joint formation, microstructural characteristics, and mechanical properties of the resulting lap joints were then investigated. The results showed that ultrasonic vibration significantly promoted the flow of metal at the interface, enlarged the size of the stirred zone (SZ), and reduced the angle between the hook defect and the interface. During lap shear testing, the FSLW and UAFSLW joints fractured in a similar manner. The fracture modes included tensile fracture, shear fracture, and a mixture of both. Cold lap and hook defects may have served as crack-initiation zones within the joint. Under configuration A (i.e., upper sheet on the retreating side (RS)), all joints failed in the shear-fracture mode. The effective lap width (ELW) of the joint welded using tool T2 was the greatest. This resulted in a higher shear fracture strength. The maximum shear fracture strength of the UAFSLW joint was 663.1 N/mm. Under configuration B (i.e., upper sheet on the advancing side (AS)), the shear fracture strength was greatly affected by the fracture mode. The highest shear fracture strength of the UAFSLW joint, 543.7 N/mm, was welded by tool T3. Thus, under otherwise identical conditions, UAFSLW joints can withstand a greater fracture shear strength than FSLW joints, as ultrasonic vibration helps to mix the material at the interface, thus, enlarging the SZ and diminishing the cold lap defects.
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Witek, Lucjan. "INFLUENCE OF PLASTIC DEFORMATION OF ADHEREND MATERIAL ON STRESS DISTRIBUTION IN ADHESIVE LAP JOINTS." Acta Metallurgica Slovaca 23, no. 4 (December 4, 2017): 304. http://dx.doi.org/10.12776/ams.v23i4.1010.
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<p class="AMSmaintext">In the engineering analysis of adhesive lap joints the linear-elastic model of adherend material is often used. In some cases, when the joined material has a low yield stress, this assumption causes errors in stress estimation in the adhesive layer or adherend. In this study the results of numerical stress and strain analysis of single lap adhesive joints were presented. In performed analysis both the linear-elastic and the elastic-plastic models of adherend materials were considered. In the first part of the work the mechanical properties of joined material were obtained using the experimental investigations. In the next part of the work the discrete model of joint was created. The results of nonlinear finite element analysis showed that in the case of joining of materials with low yield stress the plastic deformation in adherend occurs at load much smaller than destructive force of the joint. In this kind of joints the plastic deformation of adherend influences a rapid stress increase in the adhesive layer, at the final stage of loading. This phenomenon causes a decrease of strength of single lap adhesive joints of elastic-plastic materials.</p>
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Takashima, Yasuhito, Tomo Washio, and Fumiyoshi Minami. "Evaluation of Tensile Shear Strength for Lap Joint of Dissimilar Steels." Materials Science Forum 1016 (January 2021): 1454–59. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1454.
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The influence of different thickness combinations was investigated on the strength of the lap joint of dissimilar steels. In this study, lap joints of dissimilar steels were welded by laser welding. The tensile shear test was conducted for the lap joints. Rotational deformation process around the weld bead of the lap joint was observed by a digital video camera during the test. Motion analysis from the video of the tensile shear test indicated that the rotation angle around the weld bead was reduced by overlapping higher strength grade steel. Three-dimensional elastic-plastic finite element analysis was performed for the tensile shear test of the lap joint. The numerically calculated deformation behavior of the lap joint subjected to tensile shear loading showed reasonable agreement with the experimental record. It was found that the rotation angle was reduced and tensile shear strength of the lap joint increase by overlapping higher strength grade steel sheet.
11
Shi, Gang, and Yufeng Chen. "Investigation of ductile fracture behavior of lap-welded joints with 460 MPa steel." Advances in Structural Engineering 21, no. 9 (December 18, 2017): 1376–87. http://dx.doi.org/10.1177/1369433217746342.
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Fractures in welded connections usually occurred at Earthquake. The lap-welded joints are an important type of welded connections in high strength steel structures. In this article, the ductile fracture behavior of lap-welded joints has been studied experimentally and numerically with 460 MPa steel. A series of coupon tests were used to determine two corresponding weld materials (ER55-D2 and ER55-G) mechanical properties. Two micromechanics models (void growth model and stress-modified critical strain models) had been calibrated by circumferentially notched tension specimens and calculated the fracture parameters numerically, which had been applied in predicting in five lap-welded joints. The experimental study showed that the fracture mode of 460 MPa lap-welded joints exhibited plastic damage under the tension tests. Numerical analysis of the fracture parameters also showed that the ductile fracture behavior of lap-welded joint with ER55-G was better. The study establishes an accurate numerical model for analyzing the ductile fracture behavior of Q460 high strength steel lap-welded joints that is applicable in predicting the fracture failure of welded steel structures.
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Liu, Jintong, Anan Zhao, Zhenzheng Ke, Zhendong Zhu, and Yunbo Bi. "Influence of Rivet Diameter and Pitch on the Fatigue Performance of Riveted Lap Joints Based on Stress Distribution Analysis." Materials 13, no. 16 (August 16, 2020): 3625. http://dx.doi.org/10.3390/ma13163625.
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Interference-fit riveting is one of the most widely used mechanical joining ways in aircraft assembly. The fatigue performance of riveted joints has a significant impact on the service life and reliability of aircraft. In this paper, the fatigue performance of the riveted lap joints with various rivet diameters and pitches are studied based on stress distribution analysis under tensile load. First, a theoretical model of the riveted lap joint under tensile load is developed by using the spring-mass model. The rivet-load stress, bypass stress, and interference stress around the riveted hole are analyzed. Then, the finite element (FE) model of riveted lap joints are established. The influence of rivet diameter and pitch on stress distribution around the riveted hole are discussed. Finally, the fatigue tests are conducted with riveted lap joint specimens to verify the theoretical model and FE results, and a good agreement is observed. Based on the simulation and experimental results, a good combination of structural parameters of the riveted lap joint is found which can optimize the stress distribution around the riveted hole and improve the fatigue life of the riveted lap joint.
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Ye, Lingpeng, Baisheng Wang, and Pujian Shao. "Experimental and Numerical Analysis of a Reinforced Wood Lap Joint." Materials 13, no. 18 (September 16, 2020): 4117. http://dx.doi.org/10.3390/ma13184117.
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During the restoration of ancient wood structures, the original material of the structures should be kept as much as possible, so a spliced method by using lap joints is commonly used to repair ancient wood structures. This study studies the mechanical behavior of a lap joint which was reinforced with fiber composite materials or steels. An experimental and numerical analysis were performed to study the strength, stiffness and failure modes of the lap joints. The test results showed that the strengthening effect of sticking carbon fiber-reinforced polymer (CFRP) sheets is better than that of sticking CFRP bars or steel bars due to the better bonding conditions; therefore, the lap joint reinforced with CFRP sheets was further analyzed using a numerical approach. The strength and stiffness were enhanced by increasing the reinforcement ratio of CFRP sheets. The use of a 0.34% reinforcement ratio made the bearing capacity of the lap joint reach that of the intact beam. The numerical model agreed well with the experiments in terms of stiffness. By analyzing the numerical analysis results, the structural behavior of the lap joint was revealed. A numerical model can be used to predict the stiffness and behavior of spliced beams with lap joints of different sizes.
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Li, Gang, Shengyu Xu, Xiaofeng Lu, Xiaolei Zhu, Yupeng Guo, and Jufeng Song. "Effect of welding speed on microstructure and mechanical properties of titanium alloy/stainless steel lap joints during cold metal transfer method." Metallurgical Research & Technology 117, no. 5 (2020): 506. http://dx.doi.org/10.1051/metal/2020052.
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Cold metal transfer (CMT) technique is developed for lap joining of titanium (Ti) alloy to stainless steel (SS) with CuSi3 filler wire. The effect of welding speed on the microstructure and mechanical properties of Ti/SS lap joints is investigated. The results indicate that the wetting angle of the lap joints gradually increases and the weld width decreases with increasing the welding speed. It is found that many coarse phases in the fusion zone are rich in Ti, Fe and Si etc, inferring as Fe–Si–Ti ternary phase and/or Fe2Ti phase at low welding speed. Many fine spherical particles in the fusion zone are considered as iron-rich particles at high welding speed. The transition layer are exhibited at the Ti–Cu interface. With increasing the heat input, the intermetallic layer becomes thicker. A variety of brittle intermetallic compounds (IMCs) are identified in the lap joints. The shear strength of the joints increases with increasing the welding speed. Two fracture modes occur in the lap joints at low welding speed. Thicker reaction layer causes brittle fracture and poor joint strength. The Fe–Ti–Si and Fe2Ti phase within the fusion zone are detrimental to the joint strength. The fracture surface of the joints is dominated by smooth surface and tear pattern at high welding speed. The fracture mode of the joints is merely along the Ti–Cu interface.
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Imanaka, Makato, Yusuke Fukuchi, Waichiro Kishimoto, Kozo Okita, Hideaki Nakayama, and Hiroyoshi Nagai. "Fatigue Life Estimation of Adhesively Bonded Lap Joints." Journal of Engineering Materials and Technology 110, no. 4 (October 1, 1988): 350–54. http://dx.doi.org/10.1115/1.3226061.
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This paper describes a method of estimating the fatigue life of adhesively bonded lap joints on the basis of the stress analysis in adhesive layer with finite element method. First, cyclic tensile fatigue tests were conducted for adhesively bonded lap joints with different lap length and adhesive layer thickness. The results were evaluated from the viewpoint of the maximum values of both tensile and shear stress obtained numerically, instead of the apparent stress. Then these standardized fatigue strength were compared with those of adhesively bonded butt joints of a thin wall tube under cyclic tensile and fully reversed torsional load conditions. The results indicate that fatigue strength of lap joints evaluated from the maximum tensile stress of the adhesive layer agrees well with the fatigue strength of adhesively bonded butt joints of thin wall tube under cyclic tensile load condition. It is confirmed that fatigue strength of lap joints can be estimated adequately based on the fatigue strength of the butt joint of thin wall tube and the numerical results for the stress state of adhesive layer.
16
Silva, Diogo FM, Ivo MF Bragança, Carlos MA Silva, Luis M. Alves, and Paulo AF Martins. "Joining by forming of additive manufactured ‘mortise-and-tenon’ joints." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 1 (July 27, 2017): 166–73. http://dx.doi.org/10.1177/0954405417720954.
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This article is aimed at extending the ‘mortise-and-tenon’ joining concept commonly utilized in corner or tee joints to lap joints in which one sheet is partially placed over another without any change in their shape. The approach makes use of wire arc additive manufacturing to fabricate the tenons and allows various shapes and thicknesses to be made from a wide range of metallic materials. Upset compression of the tenons is utilized to mechanically lock the two sheets being joined. Experimental and finite element simulation works performed with monolithic (aluminium–aluminium) and hybrid (aluminium–polymer) ‘unit cells’ consisting of a single lap joint are utilized to investigate the deformation mechanics and the feasibility of the new proposed joining process. Tensile-shear loading tests were carried out to determine the maximum force that the new proposed joints are capable to withstand without failure. Pull-out forces of approximately 8 and 6 kN for the monolithic and hybrid joints allow concluding on the potential of additive manufactured ‘mortise-and-tenon’ lap joints to connect sheets made from similar and dissimilar materials.
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Zheng, Xiao Ling, Jia Ling Yan, Min You, Jiang Cheng Zhang, and Lai Hu Song. "Effect of Metal Block on Stress Distribution in Weld-Bonded Steel Joint." Advanced Materials Research 602-604 (December 2012): 2092–95. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.2092.
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The effect of metal block as the fillet on the stress distributed in weld-bonded single lap steel joint was investigated using elasto-plastic finite element method (FEM). The results from the numerical simulation showed that it is beneficial when the joints with a couple of right triangle metal block were adhered to both ends of the over lap. It is advantageous of reducing the peak stress in the adhesive layer near the ends of the lap zone in weld-bonded single lap steel joints so that the stress distribution in overlap zone was improved. The load-bearing capacity of the weld-bonded single lap steel joints may be elevated. There is no evidential difference in the effects between the steel and aluminum block.
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Razavi, S. M. J., M. Peron, J. Torgersen, and F. Berto. "The Effect of Interface Geometry on the Mechanical Behavior of Adhesive Joints." Key Engineering Materials 754 (September 2017): 256–59. http://dx.doi.org/10.4028/www.scientific.net/kem.754.256.
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The role of sinusoid interface shape on the load bearing capacity of the adhesively bonded single lap joints has been investigated experimentally. The experimental results showed that the interface non-flatness can considerably influence the adhesive joint strength. The main parameters that can affect the load bearing of the non-flat joints are wave heights, wave lengths and also mechanical properties of adhesives and adherends. In this paper, the effect of wave length was evaluated as the key variable parameter. According to the experimental results for the best studied case, non-flat sinusoid single lap joints had about 51% higher load bearing compared to the conventional flat single lap joints.
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Liu, Wei Jian, Wen Quan Wang, and Fan Jiang. "Microstructures and Properties of Friction Stir Welded Al-Cu Lap Joints." Materials Science Forum 953 (May 2019): 9–14. http://dx.doi.org/10.4028/www.scientific.net/msf.953.9.
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Friction stir welded lap joints of 5083 aluminum alloy plates with thickness of 2mm and T2 pure copper plates with thickness of 3mm were prepared, and the microstructures and properties of lap joints were investigated. The results showed that Al and Cu interdiffusion occurred at the interface of the lap joints, the grains in the stir zone of Al were refined and the microhardness increased sharply. The joint of Cu can be divided into four parts, including the nugget zone (NZ), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM). Using the optimum welding parameters (rotation speed of 900rpm and welding speed of 100mm/min), the lap joints were well formed. There were fewer welding defects and the average shear tensile force reached 3.155KN. Also, the ductile-brittle hybrid fracture occurred at the transitional zone of the advancing side of the Al plates. XRD results showed that intermetallic compounds (IMCS) mainly composed of Al2Cu and AlCu4 were produced in the interface of the lap joints during welding.
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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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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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Asgari Mehrabadi, Farhad. "Experimental and Numerical Failure Analysis of Adhesive Composite Joints." International Journal of Aerospace Engineering 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/925340.
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In the first section of this work, a suitable data reduction scheme is developed to measure the adhesive joints strain energy release rate under pure mode-I loading, and in the second section, three types of adhesive hybrid lap-joints, that is, Aluminum-GFRP (Glass Fiber Reinforced Plastic), GFRP-GFRP, and Steel-GFRP were employed in the determination of adhesive hybrid joints strengths and failures that occur at these assemblies under tension loading. To achieve the aims, Double Cantilever Beam (DCB) was used to evaluate the fracture state under the mode-I loading (opening mode) and also hybrid lap-joint was employed to investigate the failure load and strength of bonded joints. The finite-element study was carried out to understand the stress intensity factors in DCB test to account fracture toughness using J-integral method as a useful tool for predicting crack failures. In the case of hybrid lap-joint tests, a numerical modeling was also performed to determine the adhesive stress distribution and stress concentrations in the side of lap-joint. Results are discussed in terms of their relationship with adhesively bonded joints and thus can be used to develop appropriate approaches aimed at using adhesive bonding and extending the lives of adhesively bonded repairs for aerospace structures.
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He, Xiao Cong. "Bond Thickness Effects upon Dynamic Behaviour in Adhesive Joints." Advanced Materials Research 97-101 (March 2010): 3920–23. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.3920.
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The influence of adhesive layer thickness on the dynamic behaviour of the single-lap adhesive joints is investigated in this paper. The ABAQUS finite element analysis (FEA) software was used to predict the frequency response functions (FRFs) of the single-lap adhesive joints of different thickness of the adhesive layer. As a reference, the FRFs of a cantilevered beam without joint were investigated as well. It is clear that the FRFs of the four beams are close to each other within the frequency range 0~1000 Hz. It is also found that the composite damping of the single-lap adhesive joint increases as the thickness of the adhesive layer increases.
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Müller, M., and D. Herák. "Dimensioning of the bonded lap joint." Research in Agricultural Engineering 56, No. 2 (June 7, 2010): 59–68. http://dx.doi.org/10.17221/35/2009-rae.
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Bonded joint is a complex assembly, which creation and following use is limited by a range of factors. The primary factors are the properties of the bonded material and of the adhesive. The stress distribution in the bonded joint is substantially influenced by the bonded joint geometry and by the deformation characteristics. Laboratory experiments are intent on the above mentioned influences for bonded lap joints, which are very used in practice. The geometrical parameters of bonded joints are substantial for the constructional parameters and for costs determination. At the lower lapping length the failure of the bonded joint occurs and the maximum loading capacity of the bonded material is not fully utilized. On the contrary when using the lapping length over its optimum value the failure of the bonded material occurs. At the same time the total weight of the bonded assembly increases. Therefore it is important to determine the bonded joint optimum values which secure the reliability and which do not increase the production costs.
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Akrami, Roya, Shahwaiz Anjum, Sakineh Fotouhi, Joel Boaretto, Felipe Vannucchi de Camargo, and Mohamad Fotouhi. "Investigating the Effect of Interface Morphology in Adhesively Bonded Composite Wavy-Lap Joints." Journal of Composites Science 5, no. 1 (January 17, 2021): 32. http://dx.doi.org/10.3390/jcs5010032.
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Joints and interfaces are one of the key aspects of the design and production of composite structures. This paper investigates the effect of adhesive–adherend interface morphology on the mechanical behavior of wavy-lap joints with the aim to improve the mechanical performance. Intentional deviation from a flat joint plane was introduced in different bond angles (0°, 60°, 90° and 120°) and the joints were subjected to a quasi-static tensile load. Comparisons were made regarding the mechanical behavior of the conventional flat joint and the wavy joints. The visible failure modes that occurred within each of the joint configurations was also highlighted and explained. Load vs. displacement graphs were produced and compared, as well as the failure modes discussed both visually and qualitatively. It was observed that distinct interface morphologies result in variation in the load–displacement curve and damage types. The wavy-lap joints experience a considerably higher displacement due to the additional bending in the joint area, and the initial damage starts occurring at a higher displacement. However, the load level had its maximum value for the single-lap joints. Our findings provide insight for the development of different interface morphology angle variation to optimize the joints behavior, which is widely observed in some biological systems to improve their performance.
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Banea, Mariana D., Lucas F. M. da Silva, Raul D. S. G. Campilho, and Abílio M. P. de Jesus. "Characterization of Aluminium Single-Lap Joints for High Temperature Applications." Materials Science Forum 730-732 (November 2012): 721–26. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.721.
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In this study, an experimental investigation into the shear strength behaviour of aluminium alloy single-lap adhesive joints was carried out in order to understand the effect of temperature on the strength of adhesively bonding joints. Single lap joints (SLJs) were fabricated and tested at RT and high temperatures (100°C, 125°C, 150°C, 175°C and 200°C). Results showed that the failure loads of the single-lap joint test specimens vary with temperature and this needs to be considered in any design procedure. It is shown that, although the tensile stress decreased with temperature, the lap-shear strength of the adhesive increased with increasing of temperature up to the glass transition of the adhesive (Tg) and decreased for tests above the Tg.
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Golewski, Przemysław, and Tomasz Sadowski. "The Influence of Single Lap Geometry in Adhesive and Hybrid Joints on Their Load Carrying Capacity." Materials 12, no. 12 (June 12, 2019): 1884. http://dx.doi.org/10.3390/ma12121884.
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The manufacturing technology for adhesive joints is not yet fully optimized, as proved by a large number of papers that have been published in recent years. Future studies on innovative techniques for fabricating adhesive joints should investigate the influence of parameters such as: (1) The shape of adhesive protrusion, (2) lap dimensions, and (3) cohesive layer reduction in the most efforted regions of the joint. With the application of additional mechanical connectors (e.g., rivets, screws, and welds) in adhesive joints, new hybrid connections can be fabricated. The number of publications in this new field is still relatively small. To fill the gap, this paper presents the results of a numerical analysis of different single lap geometries in (1) pure adhesive and (2) hybrid joints. A total of 13 different models with the same surface area of the adhesive layer were considered. In the case of hybrid joints, the adhesive surface before the application of mechanical connectors was assumed to be the same in every tested case. The numerical analysis of pure adhesive and hybrid joints revealed that the differences in strength led to a 30% decrease in the load capacity of these joints. Therefore, when designing pure adhesive and hybrid joints, special attention should be paid to the shape of the lap between the joined elements.
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Mucha, Jacek, and Waldemar Witkowski. "The Structure of the Strength of Riveted Joints Determined in the Lap Joint Tensile Shear Test." Acta Mechanica et Automatica 9, no. 1 (March 1, 2015): 44–49. http://dx.doi.org/10.1515/ama-2015-0009.
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Abstract The article presents the analysis of the structure of the load capacity of riveted joints. For the four joining systems the lap joint specimens were made and tested in the shearing test. The joints were prepared for the three combinations of the DC01 steel and EN AW- 5754 aluminium alloy sheets with the thickness of 2mm. On the basis of the obtained load-elongation diagram tensile shear test curves, the basic parameters defined in the ISO/DIS 12996 standard were determined. In the case of the conventional riveted joints the maximum load capacity of the joint is determined by the strength of the fastener. For the joints with aluminium-steel blind rivet , the load capacity of the joint was on the strength limit of the rivet tubular part and on the strength limit of the sheet material. The strength of the SSPR joint is determined by the mechanical properties of the material of the joined sheets. From all sheets and rivet specimens arrangements the highest load capacity of the joint was obtained for the DC01 sheet material joints, and the lowest load capacity of the joint was obtained for the EN AW-5754 sheet material joints.
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Wang, Pei Yan, Shi Hui Huo, Fu Sheng Wang, and Zhu Feng Yue. "Experimental Study on Composites with Single-Lap Countersunk Head Bolt Joints." Advanced Materials Research 291-294 (July 2011): 848–54. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.848.
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An investigation was performed to study the response of laminated composites with bolt joints. The configuration was single-lap single countersunk head bolt. The major focus was to characterize bearing behavior of laminates and the effect of some parameters such as lap types, fastener types, hole diameter, and stiffness of lapped plate on the bearing strength and stiffness. For this purpose, hundreds of specimens were tested to obtain ultimate loads and stiffness of joints. According to different configurations of joints, three contrast tests were carried out, and some useful conclusions were drawn. Firstly, comparing the stiffness, the joints with protruding head bolts are slightly stiffer than those with countersunk head bolts. And bearing strength of the joints with protruding head bolts are about 10% higher than those with countersunk head bolts. Secondly, ultimate load and stiffness of single-lap double bolts are similar to double-lap single bolt, which are twice bigger than single-lap single bolt. Thirdly, the stiffness of joints can be improved by using bigger hole diameter or stiffer lapped plates. When the hole diameter and stiffer lapped plates are in a reasonable range, bearing strength increase. However, larger stiffness of joint structure may cause transient breaking, which is dangerous for the structure. So in engineering, it is needed to balance the bearing strength and stiffness of joints.
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Xue, Hong Qian, Qian Tao, and Emin Bayraktar. "Effect of Interference-Fit on Fatigue Life for Composite Lap Joints." Advanced Materials Research 939 (May 2014): 39–46. http://dx.doi.org/10.4028/www.scientific.net/amr.939.39.
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The aim of this study is to examine the effect of the clearance and interference-fit on the fatigue life of composite lap joints in double shear, 3D finite element simulations have been performed to obtain stress (or strain) distributions around the hole due to interference fit using FEM package, Non-linear contact analyses are performed to examine the effects of the clearance and interference for titanium and composite lap joint. Fatigue tests were conducted for the titanium and composite lap joints with clearance fit and interference fit with 0.5, 1, and 1.5% nominal interference fit levels at different cyclic loads. The results shows that interference fit increases fatigue life compared to clearance fit specimens, the titanium and composite lap joint with 1% interference fit level has the better fatigue life.
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Iwasa, Masaaki, and Toshio Hattori. "Evaluation Method for Fatigue Strength of FRP/Metal Adhesive Joints Considering Mean Stress." Journal of Engineering Materials and Technology 125, no. 4 (September 22, 2003): 402–5. http://dx.doi.org/10.1115/1.1605114.
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The fatigue strength of two types of FRP/metal adhesive joints at low temperature, a double lap joint and an embedded joint, was evaluated analytically and experimentally. First, the stress singularity parameters of the delamination edges under mechanical and thermal loadings were analyzed by FEM for various delamination lengths. The delamination propagation rate of the double lap joint under mechanical cyclic loadings at room temperature was measured. Using the relationship between the measured propagation rates and the analyzed ranges of stress singularity intensity, we estimated the fatigue strength of the embedded joint, which coincided well with the measured one. Second, we developed an evaluation method that separates the effects of temperature on fatigue strength into two effects: thermal residual stress and low temperature. Third, the fatigue strengths of the double lap joints were measured for various mean stresses. Fatigue limit of adhesive joints was experimentally measured and compared with analytical intensity of stress singularity. A method for evaluating the fatigue strength of adhesive joints by taking mean stress into account was developed.
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Katayama, Seiji, Sung Min Joo, Masami Mizutani, and Han Sur Bang. "Laser Weldability of Aluminum Alloy and Steel." Materials Science Forum 502 (December 2005): 481–86. http://dx.doi.org/10.4028/www.scientific.net/msf.502.481.
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With the intention of improving butt or lap joint of dissimilar materials, specially devised weld beads together with lap and butt-joints were produced between A5052 and SPCC, where A5052 butt-joint was melted by heat-conduction of SPCC weld bead in addition to the formation of a limited weld fusion zone at the lap part in A5052 alloy. The thickness of intermetallic compounds at the butt-joint interface was approximately 2 μm and free of cracks. It was also revealed that crack-free lap weld metals were formed between aluminum alloy and steel when the penetration was controlled to be of less than 0.3 mm in depth at small heat input. It was moreover found that the majority of a laser weld fusion zone solidified as alpha(bcc)-iron phase containing small amount of aluminum, and cracks were absent in the case of hard intermetallic (AlxFey type) layer of less than 10μm zone. It was confirmed that a weld with lap and butt joints possessed high strength (leading to the load 3500 N to 4,380 N for 40 mm width specimen). In addition, SPCC and A1100 or A5052 were subjected to lap welding with a cw YAG laser, where one to three passes were performed to produce wider bonded areas. Dissimilar steel and aluminum joints with good mechanical properties were obtained, since the fracture occurred in the aluminum alloy base metal in the tensile test. It is concluded that welded joints of high strength can be produced between aluminum alloy and steel with proper devices.
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You, Min, Lai Hu Song, Jiang Cheng Zhang, and Mei Li. "Effect of the Metal Block on the Stress Distributed in the Adhesively Bonded Single Lap Steel Joint." Advanced Materials Research 644 (January 2013): 243–46. http://dx.doi.org/10.4028/www.scientific.net/amr.644.243.
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The effect of 4 mm long metal block bonded to the end of the overlap zone on the stress distributed in adhesively bonded single lap steel joint was investigated using elasto-plastic finite element method (FEM). The results from the numerical simulation showed that the stress is varied a little when the joints with a couple of 4 mm long metal block adhered to both ends of the over lap or with a couple of adhesive fillet. Compared to the joint without the metal block, it is advantageous of reducing the peak stress in the adhesive layer near the ends of the lap zone in adhesively bonded single lap steel joints but its effect is less than that of the joint with a couple of adhesive fillet. There is no evidential difference in the effects between the steel and aluminum block.
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Her, Shiuh-Chuan, and Cheng-Feng Chan. "Interfacial Stress Analysis of Adhesively Bonded Lap Joint." Materials 12, no. 15 (July 28, 2019): 2403. http://dx.doi.org/10.3390/ma12152403.
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The use of adhesively bonded joints in place of traditional joining techniques such as bolted or rivet joints is becoming greatly popular in recent years. Interfacial stress in the adhesive is critical to the strength of adhesively bonded joints. It is necessary to predict the interfacial stresses accurately to ensure the safety of joints. In this work, an analytical model is explicitly presented to evaluate the stresses in a double lap joint. The equilibrium equations in the adhesive overlap region are derived on the basis of elasticity theory. The governing equations are presented in terms of shear and peel stresses in the adhesive. Analytical solutions are derived for the shear and peel stresses, which are considered to be the main reason for the failure of the double lap joint. To verify the analytical solutions, the finite element method is conducted using the commercial package ANSYS. Results from the analytical solution agree well with finite element results and numerical investigations available in the literature. The effect of the adhesive thickness, shear modulus, adherend Young’s modulus and bonding length on the shear and peel stresses in the adhesive of the double lap joint are studied. Numerical results demonstrate that both the maximum shear and peel stress occur at both ends of the bonding region. The maximum values of the shear and peel stresses increase as the adhesive thickness decreases and as the adhesive shear modulus increases provided that the adhesive thickness is sufficiently small. The simplicity and capability to obtain analytical expressions of the shear and peel stresses for double lap adhesive bonded joints makes the proposed analytical model applicable for the stress analysis and preliminary structural design.
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Bula, Karol, Tomasz Sterzyński, Maria Piasecka, and Leszek Różański. "Deformation Mechanism in Mechanically Coupled Polymer–Metal Hybrid Joints." Materials 13, no. 11 (May 31, 2020): 2512. http://dx.doi.org/10.3390/ma13112512.
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In this, work, metal inserts were joined with polyamide 6 by using the injection-molding technique. The metal parts, made of steel grade DC 04, were mechanically interlocked with polyamide 6 (PA6) by rivets as a mechanical connection between both components in the form of s polymer filling the holes in the metallic parts. The mechanical-interlocking joints made of steel/PA6 were mechanically tested in a tensile-lap-shear test. The damage behavior of the joined materials in relation to rivet number and position on the metal plate was studied. The observation of rivet deformation was also conducted by infrared IR thermography. The study showed that, for polymer–metal joined samples with fewer than three rivets, the destruction of rivets by shearing meant sample damage. On the other hand, when the polymer–metal joint was made with three or four rivets, the disruption mechanism was mostly related to the polymer part breaking. The maximal values of the joint’s failure force under tensile-shear tests were achieved for samples where three rivets were used. Moreover, strong correlation was found between the surface temperature of the samples and their maximal force during the tensile-lap-shear test.
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Aldanondo, Egoitz, Javier Vivas, Pedro Álvarez, and Iñaki Hurtado. "Effect of Tool Geometry and Welding Parameters on Friction Stir Welded Lap Joint Formation with AA2099-T83 and AA2060-T8E30 Aluminium Alloys." Metals 10, no. 7 (July 1, 2020): 872. http://dx.doi.org/10.3390/met10070872.
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In this paper the effect of tool geometry and welding parameters on friction stir welded lap joints with AA2099-T83 and AA2060-T8E30 aluminium alloys has been investigated through the study of the material flow and weld formation along with the reaction forces during friction stir welding (FSW) for various sets of welding parameters and two FSW tools with different geometrical features. The results showed that welding parameters and tool probe geometry strongly affect the characteristics of the typical defect features (hook and cold lap defects) of the friction stir welded lap joints. From the relationship established between the welding parameters, tool probe geometry and the hook and cold lap defect formation, some guidelines are concluded with the objective of guaranteeing appropriate FSW lap joint properties.
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Tong, L. "Strength of adhesively bonded single-lap and lap-shear joints." International Journal of Solids and Structures 35, no. 20 (July 1998): 2601–16. http://dx.doi.org/10.1016/s0020-7683(97)00174-1.
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Krasnowski, K. "Fatigue and Static Properties of Friction Stir Welded Aluminium Alloy 6082 Lap Joints Using Triflute-Type and Smooth Tool." Archives of Metallurgy and Materials 59, no. 1 (March 1, 2014): 157–62. http://dx.doi.org/10.2478/amm-2014-0025.
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Abstract Due to numerous advantages, the FSW process more and more frequently used in different industries. Presently 99% of the FSW applications are connected with welding of aluminium alloys and most of FSW connections are butt joints, for which the very good mechanical properties are proved in many research. Instead of butt joints also a few types of shape joints can be friction stir welded, e.g. lap joints, multiple lap joints, fillet joints and T-joints. This study presents the results of investigation into the impact of the FSW tool type on the structure of FSW lap joints made of aluminium 6082 and their mechanical properties under static and dynamic load. The study also presents the influence of different welding speeds and toll pin lengths on structure of lap joints. The paper also describes and demonstrates the negative influence on joints properties of some common defects that usually occurs in lap joints welded by means of FSW.
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Kang, Hong-Tae, and Sai Boorgu. "Fatigue Life Prediction of Self-Piercing Rivet Joints Between Magnesium and Aluminum Alloys." MATEC Web of Conferences 165 (2018): 10004. http://dx.doi.org/10.1051/matecconf/201816510004.
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Various light materials including aluminum alloys and magnesium alloys are being used to reduce the weight of vehicle structures. Joining of dissimilar materials is always a challenging task to construct a solid structure. Self-piercing rivet (SPR) joint is one of various joining methods for dissimilar materials. Front shock tower structures were constructed with magnesium alloy (AM60) joined to aluminum alloy (Al6082) by SPR joints. To evaluate the durability performance of the SPR joints in the structures, fatigue tests of the front shock tower structures were conducted with constant amplitude loadings. Furthermore, this study investigated fatigue life prediction method of SPR joints and compared the fatigue life prediction results with that of experimental results. For fatigue life prediction of the SPR joints in the front shock tower structures, lap-shear and cross-tension specimens of SPR joint were constructed and tested to characterize the fatigue properties of the SPR joint. Then, the SPR joint was represented with area contact method (ACM) in finite element (FE) models. The load-life curves of the lap-shear and cross-tension specimens were converted to a structural stress-life (S-N) curve of the SPR joints. The S-N curve was used to predict fatigue life of SPR joints in the front shock tower structures. The test results and the prediction results were well correlated.
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Wang, Yuqi, Yanhui Li, and Kaixuan Zhou. "Influence of Reinforcement Length on Singularity of Single-Lap Joints." Advances in Materials Science and Engineering 2018 (July 18, 2018): 1–8. http://dx.doi.org/10.1155/2018/2801691.
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In order to enhance the strength of single-lap joints, the single-lap joints with reinforcements were proposed. The influence of reinforcement length on the singular behavior near to the interface point of single-lap joints was investigated theoretically and numerically. The theoretical strength of singularity point was calculated by Bogy determinant. Stresses along the interface close to the singularity points were calculated with finite element analyses (FEAs). Results showed that the singular stress intensity factor of single-lap joints can be decreased by the reinforcement. However, the singular stress intensity factor of single-lap joints with reinforcements was decreased slightly with increasing reinforcement length.
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Kendall, Kevin. "Energizing ASTM lap joint fracture standards." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2203 (June 21, 2021): 20200287. http://dx.doi.org/10.1098/rsta.2020.0287.
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Several ASTM standards on the fracture of glued and welded joints need attention because they do not consider the Griffith energy criterion of cracking which was proposed a century ago. It is almost as if Griffith never existed because the ASTM definition of failure is the stress criterion postulated by Galileo in 1638 in which stress at failure (i.e. strength = force/area) is defined as the determinant of fracture. Irene Martinez Villegas (Villegas, Rans 2021 Phil. Trans. R. Soc. A 376, 20200296. ( doi:10.1098/rsta.2020.0296 )) shows in this volume that attempts to use ASTM D5868 to standardize welded composite (carbon fibre reinforced polymer, CFRP) lap joints reveal major problems. First, the test is a low angle bend–peel test; not shear. Second, the energy required to break the joint is not emphasized so that joints may have high strength properties but also low toughness; third, the fracture force is not proportional to the lap joint area so the concept of strength independent of sample size is false; fourth, as the CFRP panels are made thicker, the strength rises at constant overlap area so the strength can be any value you want; fifth, the strength of larger joints goes down; this is the size effect noted in many bend-cracking tests, much as Galileo suggested for bent beam fracture in his famous book ‘the larger the machine, the greater its weakness'. The purpose of this paper is to demonstrate that poor ASTM ‘shear strength’ standards should be replaced by a definition of welded lap joint performance based on Griffith's energy conservation argument in which fracture surface energy is the main parameter resisting failure. The foundation of this Griffith-style lap joint analysis for long cracks goes back to 1975 but has been largely ignored until now because it does not fit the Griffith equation for cracked sheets, has no ‘stress intensity factor’, and travels at constant speed, not accelerating like the standard Griffith tension crack. This study of tensile delamination shows that a long lap crack is not driven by stress near the crack but by changes in stored elastic energy in the stretched strips remote from the crack tip, while strain energy release rate is negative. It would be more appropriate to call this lap failure a tensile delamination crack. This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction’.
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Goushegir, Seyed Mohammad, Jorge F. dos Santos, and Sergio T. Amancio-Filho. "Fatigue Performance of Metal–Composite Friction Spot Joints." Materials 14, no. 16 (August 11, 2021): 4516. http://dx.doi.org/10.3390/ma14164516.
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Friction spot joining is an alternative technique for joining metals with polymers and composites. This study investigated the fatigue performance of aluminum alloy 2024/carbon-fiber-reinforced poly(phenylene sulfide) joints that were produced with friction spot joining. The surface of the aluminum was pre-treated using various surface treatment methods. The joined specimens were tested under dynamic loading using a load ratio of R = 0.1 and a frequency of 5 Hz. The tests were performed at different percentages of the lap shear strength of the joint. Three models—exponential, power law, and wear-out—were used to statistically analyze the fatigue life of the joints and to draw the stress–life (S–N) curves. The joints showed an infinite life of 25–35% of their quasi-static strength at 106 cycles. The joints surpassing 106 cycles were subsequently tested under quasi-static loading, showing no considerable reduction compared to their initial lap shear strength.
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Chen, Yue Liang, Da Zhao Yu, and Cheng Mei Duan. "A Numerical Study of MSD in Aircraft Lap Joints." Key Engineering Materials 324-325 (November 2006): 927–30. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.927.
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Many military aircraft have reached or exceeded their original design life, and have been subject to significant increase in maintenance and repair cost due to multiple site damage (MSD). In order to assessing the effects of MSD on the structural integrity of aircraft lap joints, the wing lap joint of certain model military aircraft with MSD was analyzed using special code FRANC2D/L. The rivet holes along the top row of the outer skin of lap joint were considered as the independent structural unit for the simulated MSD cracks. The stress intensity factors (SIFs) at each crack tip with different distribution loads at the rivet holes were computed and show that the analysis results have good coherence with the available literature data. It also shows that the SIF at each crack tip s a function of crack length can be calculated by the crack growth simulation capability of FRANC2D/L. The SIF values are not sensitive to the rivet load distribution manner, which has seriously influence on MSD crack growth direction. Rivet loading can be best molded quadratic load distribution over one half of rivet hole relative to uniform load distribution and point load. As a result of this analysis, it is postulated that for MSD in aircraft lap joints, compliance measurements may provide a useful tool for assessing the structural integrity of the lap joints.
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Mulyanto, Achmad Ryan, Hendri Syamsudin, and Djarot Widagdo. "Mechanical Behavior Analysis of Apus Bamboo (Gygantochloa sp) Thin Plate Composite due to Adhesive Joint and Water Absorption Using Experimental and Finite Element Method." Advanced Materials Research 1125 (October 2015): 89–93. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.89.
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The mechanics of adhesive-lap joints of apus bamboo thin plate composite were investigated experimentally and numerically. Tensile load were applied to determine mechanical strength of adhesive joint overlaps. Modal analysis were employed to determine natural frequency of bamboo apus single-lap joint for different overlap and plate thickness configurations. This research found the strength of bamboo adhesive joints decreased 11% due to the effect of 24 hours water immersion. Natural frequencies of single-lap adhesive joint configuration were equivalently decreased in decreament of overlap joint and thickness plate. Finite element models using ABAQUS Software were developed for static and dynamic analysis and compared with the experimental results. Compared to experimental results, numerical analysis gives the prediction with 4% difference for the mean shear stress at failure, and 7-12% difference for the natural frequencies.
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Piekarska, Wiesława, Alžbeta Sapietová, Zbigniew Saternus, and Marcin Kubiak. "Computer analysis of thermal phenomena and deformation in lap joint welded by a laser beam." MATEC Web of Conferences 157 (2018): 02040. http://dx.doi.org/10.1051/matecconf/201815702040.
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Laser welding technology is applied to many types of welded joints. The determination of the influence of technological parameters on the properties of resulting joint is a significant problem for technologists. Numerical estimation of the shape of the weld and its deformation is important in the initial stage of construction design. The paper concerns computer analysis of thermal and mechanical phenomena in laser welded lap joint made of austenitic steel. Three dimensional discrete model of analyzed lap joint is created in Abaqus FEA engineering software. Numerical analysis takes into account temperature dependent thermomechanical properties of austenitic steel. The movable heat source power distribution is modelled using Gaussian distribution. Computational model takes into account the gap between the joined plates. Temperature distribution in analysed joints is presented on the basis of performed numerical simulations. The shape and size of the fusion zone as well as deformation of the joint are estimated.
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Dourado, Marco Daniel Malheiro, and José Filipe Bizarro de Meireles. "A Simplified Finite Element Riveted Lap Joint Model in Structural Dynamic Analysis." Advanced Materials Research 1016 (August 2014): 185–91. http://dx.doi.org/10.4028/www.scientific.net/amr.1016.185.
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This paper proposes a simplified finite element model to represent a riveted lap joint in structural dynamic analysis field. The rivet is modeled byspring-damperelements. Several numerical models are studied with different quantities of rivets (1, 3 and 5) andspring-damperelements (4, 6, 8, 12, 16 and 20) per rivet. In parallel, samples of two aluminum material plates connected by different quantities of rivets (1, 3 and 5) are built and tested in order to be known its modal characteristics – natural frequencies and mode shapes. The purpose of the different settings is to get the best numerical riveted lap joint representation relatively to the experimental one. For this purpose a finite element model updating methodology is used. An evaluation of the best numerical riveted lap joint is carried out based on comparisons between the numerical model after updating and the experimental one. It is shown that the riveted lap joints composed by eight and twelvespring-damperelements per rivet have the best representation. A stiffness constant valuekis obtained for the riveted lap joints in study.
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Lu, Yi, Xiao Cong He, and Yi Feng Wang. "Study on Mechanical Properties of Self-Piercing Riveted Joints about Titanium Alloy." Applied Mechanics and Materials 723 (January 2015): 856–59. http://dx.doi.org/10.4028/www.scientific.net/amm.723.856.
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Adopting self-piercing riveting (SPR) joining, a new light sheet material joining method, to examine the joining of copper-titanium alloy (H62-TA1) sheet and titanium-aluminum alloy (TA1-Al5052) sheet. Also, using quasi-static mechanical test to figure out mechanical properties of H62-TA1 SPR single-lap joint and TA1-Al5052 SPR single-lap joint. In this study, using Dixon guidelines to eliminate abnormal value and adopting coefficient of variation method to validate reliability of test datum. The results show that failure mode of H62-TA1 joints is that the rivets are pulled out, failure mode of TA1-Al5052 joints is that the bottom sheet fracture. And tensile displacement and energy absorption of H62-TA1 joints are higher than that of TA1-Al5052 joints.
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Yu, Da Zhao, Yue Liang Chen, Yong Gao, Wen Lin Liu, and Yong Zhang. "Modeling of Pillowing Stress in Corroded Lap Joints." Advanced Materials Research 189-193 (February 2011): 2139–43. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.2139.
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Based on chemical composition of the corrosion product, a mathematical model was developed to predict the extent of the pillowing deformation of lap joints of LY12CZ in term of thickness inside the joint. The model can offer the capability for predicting the extent of corrosion within the joint in terms of thickness loss at the internal surfaces of the skins from the amplitude of the pillowing of the outer skin. Three-dimensional finite element model of a bolted joint have been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with the mathematical model. The results show that corrosion pillowing can significantly increase the stress in a lap joint for material loss below the detection limit of current nondestructive inspection techniques, thus increasing the risk of premature cracking. In addition, the analyses show that the locations of maximum stress of lap joint will change with the material loss increases. Simulating the effect of corrosion on lap joint only by reducing the panel thickness will result in neoconservative life estimates if corrosion pillowing is ignored.
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Yan, Jia Ling, Min You, Xiao Ling Zheng, Ding Feng Zhu, and Mei Rong Zhao. "The Effect of Fillet Geometry on Stress in Weld-Bonded Joints." Advanced Materials Research 97-101 (March 2010): 767–70. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.767.
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The influence of fillets with different geometry shape on the stress distribution in aluminum alloy weld-bonded single lap joint was investigated using elasto-plastic finite element method (FEM). The results show that it is advantageous of reducing stress concentration in adhesive layer near the ends of the lap zone in single lap weld-bonded aluminum joints and part of the stress transferring from adhesive layer to the nugget when the joints with a couple of right triangle fillets over other shapes. The load-bearing capacity of the whole weld-bonded joints may be improved. The full-triangular fillet is recommended that it be more advantageous of decreasing the stress peak value and making the stress distribution in overlap zone more uniform.
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Mori, K., and T. Sugibayashi. "Deformation and strength of stepped-lap joints bonded with adhesive resin." Journal of Strain Analysis for Engineering Design 27, no. 3 (July 1, 1992): 171–75. http://dx.doi.org/10.1243/03093247v273171.
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Deformation and strength of stepped-lap bonded joints under static tensile loading are investigated both analytically and experimentally. The joints used in this study consist of the same metal adherends of carbon steel and an adhesive of epoxy resin. The effects of the overlap length and number of steps on the joint strength are studied. The joint strength is predicted by applying the strength criteria on the adherends, the adhesive and their interfaces in the joint. The predicted results agree fairly well with the experimental initial cracking strengths. The experimental final fracture strengths of the joints increase with the overlap length and with the number of steps.