Failure Mechanism of Laser Welds in Lap-Shear Specimens of a High Strength Low Alloy Steel

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Jaewon Lee ◽  
Kamran Asim ◽  
Jwo Pan

In this study, the failure mechanism of laser welds in lap-shear specimens of a high strength low alloy (HSLA) steel under quasi-static loading conditions is examined based on the experimental and computational results. Optical micrographs of the welds in the specimens before tests were examined to understand the microstructure near the weld. A micrographic analysis of the failed welds in lap-shear specimens indicates a ductile necking/shear failure mechanism near the heat affected zone. Micro-hardness tests were conducted to provide an assessment of the mechanical properties of the joint area which has varying microstructure due to the welding process. A finite element analysis was also carried out to identify the effects of the weld geometry and different mechanical properties of the weld and heat affected zones on the failure mechanism. The results of the finite element analysis show that the geometry of the weld protrusion and the higher effective stress–plastic strain curves of the heat affected and weld zones result in the necking/shear failure of the load carrying sheet. The deformed shape of the finite element model near the weld matches well with that near a failed weld. A finite element analysis based on the Gurson yield function with consideration of void nucleation and growth was also carried out. The results of the finite element analysis indicate that the location of the material elements with the maximum void volume fraction matches well with that of the initiation of ductile fracture as observed in the experiments.

Author(s):  
Kamran Asim ◽  
Jaewon Lee ◽  
Jwo Pan

In this study, the failure mechanism of laser welds in lap-shear specimens of a high strength low alloy (HSLA) steel under quasi-static loading conditions is examined based on the experimental results. Optical micrographs of the welds in specimens before tests were examined to understand the microstructure near the weld. A micrographic analysis of the failed welds in lap-shear specimens indicates a ductile necking/shear failure mechanism near the heat affected zone. Micro-hardness tests were conducted to provide an assessment of the mechanical properties of the joint area which has varying microstructure due to the welding process. A finite element analysis was also carried out to identify the effects of the weld geometry and different mechanical properties of the weld and heat affected zones on the failure mechanism. The computational results of the finite element analysis indicate that the material inhomogeneity and geometry of the weld bead play an important role in the ductile necking/shear failure mechanism. The computational results match well with the experimental observations of the necking/shear failure and its location. A finite element analysis with consideration of void nucleation and growth based on the Gurson yield function was also carried out. The results of the finite element analysis based on the Gurson yield function are in good agreement with the experimental observations of the initiation of ductile fracture and its location.


2013 ◽  
Vol 461 ◽  
pp. 57-62
Author(s):  
Xiao Ting Jiang ◽  
Ce Guo ◽  
Xiu Yan Cao ◽  
Zhen Yu Lu

Based on the microstructure of the cross-section of the beetle's elytra, a kind of bio-inspiredlightweight structure was designed and made by the carbon fiber material. The compressive andshear mechanical properties of the lightweight structures were studied with finite element method.In addition, quasi-static compression experiments of the structure samples were carried out. Theexperimental results and the finite element analysis results were compared and analyzed, whichproved the effectiveness of the finite element analysis.


2012 ◽  
Vol 184-185 ◽  
pp. 534-537
Author(s):  
Jing Jing Zhou ◽  
Ai Dong Guo ◽  
Chun Hui Li ◽  
Zhen Jiang Lin ◽  
Tie Zhuang Wu

By setting contact sets, achieved overall analysis results of the mechanical properties with omni-direction side-loading forklift truck lifting system based on COSMOSWorks. And made an experimental measurements to omni-direction side-loading forklift truck lifting system by electrometric methods. There was a good relevance between experimental data and calculation values, and the deviation was basically within the 10 percent allowed. Finally, in this way it verified the correctness and reliability of the finite element analysis by experimental measurements. Ensured the omni-direction side-loading forklift truck lifting system could be safe and efficient to work. And also it laid a foundation for subsequent structural optimization.


2011 ◽  
Vol 368-373 ◽  
pp. 1038-1041
Author(s):  
An Hong Bao ◽  
Zhen Yu Qiu ◽  
Peng Wang

Debonding of concrete occurs when the interface principal stress reaches the ultimate tensile strength. We propose the use of carbon fiber plate attached to the beam bottom, which makes finite element analysis of the mechanical properties of debonding concrete beams more reasonable. In addition, formulas of this theory are given and applied in the finite element analysis. Finally, it is shown by a number of experimental results.


e-Polymers ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 83-88
Author(s):  
Yi-Chang Lee ◽  
Ho Chang ◽  
Ching-Long Wei ◽  
Rahnfong Lee ◽  
Hua-Yi Hsu ◽  
...  

AbstractThe molecular chains of a highly oriented polymer lie in the same direction. A highly oriented polymer is an engineering material with a high strength-to-weight ratio and favorable mechanical properties. Such an orthotropic material has biaxially arranged molecular chains that resist stress in the tensile direction, giving it a high commercial value. In this investigation, finite element analysis (FEA) was utilized to elucidate the deformation and failure of a highly oriented polymer. Based on the principles of material mechanics and using the FEA software, Abaqus, a solid model of an I-beam was constructed, and the lengths of this beam were set based on their heights. Three-point bending tests were performed to simulate the properties of the orthotropic highly oriented polymer, yielding results that reveal both tension failure and shear failure. The aspect ratio that most favored the manufacture of an I-beam from highly oriented polymers was obtained; based on this ratio, a die drawing mold can be developed in the future.


2011 ◽  
Vol 94-96 ◽  
pp. 2153-2156
Author(s):  
Dong Ling Yu

The mainframe of high-pressure grouting machine used for daily ceramics is the main load bearing member, and it has high strength and stiffness requirements. The finite element static analysis on mainframe is discussed in this paper for researching its stress and transfiguration. The result can provide reference for design, and the discussion has some generality and practical value engineering.


2021 ◽  
Vol 272 ◽  
pp. 02017
Author(s):  
Xiaomeng Zhang ◽  
Weilun Ding ◽  
Qingying Ren ◽  
Wenting Liu ◽  
Qiaji Wang

In this paper, a new type of prefabricated concrete structure system is put forward, and a new type of bi-directional multi-ribbed floor is put forward in combination with this system.Finite element analysis is carried out on the floor, and its mechanical properties are analyzed, and compared with the test hysteresis curve, the rationality and correctness of the finite element analysis are obtained.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wencke Krings ◽  
Jordi Marcé-Nogué ◽  
Stanislav N. Gorb

AbstractThe radula, a chitinous membrane with embedded tooth rows, is the molluscan autapomorphy for feeding. The morphologies, arrangements and mechanical properties of teeth can vary between taxa, which is usually interpreted as adaptation to food. In previous studies, we proposed about trophic and other functional specialisations in taenioglossan radulae from species of African paludomid gastropods. These were based on the analysis of shape, material properties, force-resistance, and the mechanical behaviour of teeth, when interacting with an obstacle. The latter was previously simulated for one species (Spekia zonata) by the finite-element-analysis (FEA) and, for more species, observed in experiments. In the here presented work we test the previous hypotheses by applying the FEA on 3D modelled radulae, with incorporated material properties, from three additional paludomid species. These species forage either on algae attached to rocks (Lavigeria grandis), covering sand (Cleopatra johnstoni), or attached to plant surface and covering sand (Bridouxia grandidieriana). Since the analysed radulae vary greatly in their general size (e.g. width) and size of teeth between species, we additionally aimed at relating the simulated stress and strain distributions with the tooth sizes by altering the force/volume. For this purpose, we also included S. zonata again in the present study. Our FEA results show that smaller radulae are more affected by stress and strain than larger ones, when each tooth is loaded with the same force. However, the results are not fully in congruence with results from the previous breaking stress experiments, indicating that besides the parameter size, more mechanisms leading to reduced stress/strain must be present in radulae.


2021 ◽  
Vol 871 ◽  
pp. 234-239
Author(s):  
Sheng Li Yan ◽  
Hao Li ◽  
Fei Zhan

The study aims to explore the preparation of aviation mechanical carbon fiber reinforced plastics (CFRP) and the properties of CFRP composites. Taking the aero box body as an example, the mechanical properties of CFRP are studied. The preparation of CFRP is analyzed by searching the data. CFRP plates are explored according to the stress analysis of composite materials. The finite element analysis software ANSYS Workbench and UG software are adopted to build the 3D model of the aero box body. After adding materials in ANSYS Workbench and simplifying the UG model, the finite element analysis of the model is carried out by computer. The 3D model of the aero box is constructed, the finite element analysis of the aero box is carried out, and the mechanical properties of CFRP are explored. In this study, the possibility of the practical application of CFRP in the aviation box body lightweight is clarified, which gives a direction for the subsequent actual molding and guides the application of CFRP in aviation field.


2010 ◽  
Vol 163-167 ◽  
pp. 1029-1032
Author(s):  
He Meng ◽  
Kun Yang ◽  
Qing Xuan Shi ◽  
Jin Jie Men

The finite element analysis of high-strength concrete columns confined by high-strength spiral lateral ties under concentric compression is introduced in this paper. The variables of tie strength, tie spacing and tie configuration influencing the characteristics of confined concrete are discussed; and the stress distributions of lateral ties and concrete at cross-section are analyzed. Compared with the test results, this finite element analysis can predict well the behavior of axially loaded concrete confined by lateral ties. It’s indicated that after peak load, normal stirrups loss the effective constraint on concrete due to yielding early, while the high-strength stirrups can continue to provide larger constraint which can improve significantly the ductility of confined concrete.


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