scholarly journals Equal Load-Carrying Design of Lapped Joints of Al–Cu Dissimilar Materials

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4293
Author(s):  
Zhihao Chen ◽  
Jianxiao Ma ◽  
Hongyuan Fang ◽  
Zhida Ni ◽  
Ping Wang

In order to avoid the adverse effects of additional moment and stress concentration of traditional lap joints, a new lap joint was put forward, according to the concept of “equal load-carrying”. Through static analysis and brazing characteristics consideration, the equal load-carrying design method of Al–Cu lap joint based on brazing method was established. Through three types of brazing, the relationship among two fracture modes, brazing process and static tension curve of lap joint, was analyzed. The results demonstrated that the selection of solder was required to simultaneously meet the requirements of brazability and mechanical properties. A certain relationship existed between the fracture mode of the lap joint and the static tensile curve, while the segments of the static tensile curve corresponded to the fracture paths of the two fracture modes. When the brazing holding time was quite short, the interface bonding was poor, while the bearing capacity of the joint was low; when the holding time was suitable, the bearing capacity of the joint reached the corresponding highest, while the fracture mode conformed to the equal load-carrying design; when the brazing holding time was quite long, the bearing capacity of the joint remained at a high level, but the fracture mode was the same as the holding time was quite short.

Author(s):  
SMJ Razavi ◽  
MR Ayatollahi ◽  
M Samari ◽  
LFM da Silva

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.


2021 ◽  
Author(s):  
Markus Krutzlinger ◽  
Michael Karl Kick ◽  
Manuel Kessler ◽  
Michael Friedrich Zaeh

Abstract Many studies demonstrated the suitability of Friction Stir Welding (FSW) for joining dissimilar materials. Especially the combination of aluminum and copper is of high interest for many applications. Intermetallic compounds (IMC) forming during FSW due to interdiffusion and the thickness of the IMC layers strongly influence the joint properties, e.g. the joint strength or the thermal and electrical conductivity. Therefore, it is important to predict the IMC layer thickness to tailor the joint properties to the individual application. For this purpose, a thermal-pseudo-mechanical model was built to simulate the temperature field during FSW of aluminum EN AW-1050 and copper CW008A in lap joint configuration. The simulated temperatures as well as the heat inputs corresponded well with experimental data for a wide range of parameter settings. In order to estimate the IMC layer thickness, the simulated temperatures close to the interface of the materials were used. Two approaches for calculating the layer thicknesses were compared. In the first approach, the thickness is calculated based on the peak temperature lasting for several seconds at the interfacial area. This approach was applied for constant feed rates, while the second approach also accounted for the cooling slope and could therefore be used for different feed rates.


Author(s):  
Ramakrishna Koganti ◽  
Adrian Elliott ◽  
Cindy Jiang

With the increasing demand for safety, energy saving and emission reduction, Advanced High Strength Steels (AHSS) have become very attractive steels for automobile makers. The usage of AHSS steels is projected to grow significantly in the next 5–10 years with new safety and fuel economy regulations. These new steels have significant manufacturing challenges, particularly for welding and stamping. Welding of AHSS remains one of the technical challenges in the successful application of AHSS in automobile structures due to heat-affected zone (HAZ) at the weld joint. In this study Gas Metal Arc Welding (GMAW) of a lap joint configuration consisting of 1.4 mm uncoated DP980 to itself was investigated. The objective of the study was to understand the wire feed rate and torch speed influence on lap joint tensile strength (static and fatigue). A two factor, two level, full factorial design of experiment (DOE) was conducted to understand the wire feed and torch speed influence on tensile and fatigue strength of the welded joints. In order to understand the curvature effect, a center point was also included in the experiment. Based on the statistical analysis, neither factor was significant on static tensile strength, however, a two way interaction between wire feed rate and torch speed was significant on static tensile strength. Metallurgical properties of the lap joints were evaluated using optical microscopy. A significant hardness drop of 40% was observed at the HAZ.


Author(s):  
Ramakrishna Koganti ◽  
Sergio Angotti ◽  
Armando Joaquin ◽  
Cindy Ziang ◽  
Chris Karas

With the increasing demand for safety, energy saving and emission reduction, Advanced High Strength Steels (AHSS) have become very attractive steels for automobile makers. The usage of AHSS steels is projected to grow significantly in the next 5–10 years with new safety and fuel economy regulations. These new steels have significant manufacturing challenges, particularly for welding and stamping. Welding of AHSS remains one of the technical challenges in the successful application of AHSS in automobile structures due to Heat affected Zones (HAZ) at the weld joint. In this study Gas Metal Arc Welding (GMAW) of a lap joint configuration consisting of 1.5 mm uncoated DP600 to itself was investigated. The objective of the study was to understand the wire feed rate and torch speed influence on lap joint strength. A two factor, two level, full factorial design of experiment (DOE) was conducted to understand the wire feed and torch speed influence on tensile strength. In order to understand the curvature effect, center point was also considered in the experiment. Based on the statistical analysis, wire feed rate was the only significant factor on static tensile strength. Metallurgical properties of the lap joints were evaluated using optical microscopy. Significant hardness drop of 40% was observed at the HAZ.


2012 ◽  
Vol 629 ◽  
pp. 131-138 ◽  
Author(s):  
Jian Lin ◽  
Nin Shu Ma ◽  
Yong Ping Lei ◽  
Hidekazu Murakawa

In order to save fuel consumption by reducing the weight of automobile body, the use of aluminum alloys has a great advantage. However, how to join aluminum alloys with steels becomes a big problem in the assembly lines. Cold metal transfer (CMT) is a promising joining process for steel/Al dissimilar materials. To evaluate the shear strength and to investigate the failure modes of CMT brazed lap joints of dissimilar materials, both experimental observation and numerical simulation are performed. A numerical model for the failure criteria of the interface layer failure between steel and aluminum is developed. The interface layer of CMT brazed lap joint can be modeled by the interface element. The failure stress and failure energy at the interface element are proposed as the failure criteria for the prediction of shear strength of CMT lap joints. If steel sheet thickness becomes thicker, stress distribution and concentration at interface layer elements have some change and shear strength at the interface layer can be improved. Then the failure occurring at the interface element may transfer to the fusion line at the side of the aluminum alloy sheet.


2011 ◽  
Vol 279 ◽  
pp. 219-223
Author(s):  
Guo Hua Zhao ◽  
Qing Lian Shu ◽  
Bo Sheng Huang

Spew fillet is common in co-cured composite single lap joint. It plays an important role in the safety of the joint. But few attentions were paid to the subject in former investigations. In this paper, co-cured composite single lap joints with spew fillets under static tensile load were investigated numerically using the commercial finite element code ANSYS. The submodeling technique was employed to overcome the problem caused by extra aspect ratio of elements. The computation results indicated that the existence of spew fillets will not change the possible failure location, but will improve the anti-failure performance of single lap joint.


2007 ◽  
Vol 34 (12) ◽  
pp. 1542-1553 ◽  
Author(s):  
Angus C.C. Lam ◽  
J.J. Roger Cheng ◽  
Michael C.H. Yam ◽  
Gaylene D. Kennedy

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.


Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 320-328
Author(s):  
Delin Sun ◽  
Minggao Zhu

Abstract In this paper, the energy dissipation in a bolted lap joint is studied using a continuum microslip model. Five contact pressure distributions compliant with the power law are considered, and all of them have equal pretension forces. The effects of different pressure distributions on the interface stick-slip transitions and hysteretic characteristics are presented. The calculation formulation of the energy dissipation is introduced. The energy dissipation results are plotted on linear and log-log coordinates to investigate the effect of the pressure distribution on the energy distribution. It is shown that the energy dissipations of the lap joints are related to the minimum pressure in the overlapped area, the size of the contact area and the value of the power exponent. The work provides a theoretical basis for further effective use of the joint energy dissipation.


2016 ◽  
Vol 3 ◽  
pp. 52-55 ◽  
Author(s):  
Rainer Pauska ◽  
Umut Cakmak ◽  
Rainer Lottes ◽  
Zoltan Major

Joining experiments using different adhesives were carried out. In addition to the adhesive, the specimens were also treated with ultrasonic waves to improve the load carrying capacity of the joined parts. Lap joint shear tests have been conducted to quantify this improvement.


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