EFFECT OF FATIGUE TEST ON SPOT WELDED STRUCTURAL JOINT

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Mohammad Khalid Wahid ◽  
Muhammad Nabil Muhammed Sufian ◽  
Mohamed Saiful Firdaus Hussin
Keyword(s):  
Life Cycle ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Spot Welding ◽  
Fatigue Testing ◽  
Fatigue Stress ◽  
Component Design ◽  
Welded Structure ◽  
Different Thickness ◽  
Spot Welded

Spot welding is mainly used method in joining sheet metals for body structure in automotive industry. The comprehension of the fatigue strength for the spot welds is very critical in automotive component design. Parameter for the resistance spot welding and fatigue machines is constant for each specimen used. The S-N curve is obtained from the fatigue testing for each specimen. This experiment parameters are varies the different thickness and different material combination in spot welding structure to investigate the fatigue life cycle and fatigue stress. For 1050A aluminium joint, fatigue life cycle and fatigue strength will decrease from number of cycle 500 at 16.58 MPa to number of cycle 61 at 6.62 MPa as the thickness increase. The fatigue life cycle and fatigue stress for galvanized iron will increase from number of cycle  46 at 9.25 MPa to number of cycle  1500 at 57.8 MPa when the thickness of joint increase. The finding from the combination of 1050A aluminum and galvanized iron on spot welded structure has shown no improvement in term of fatigue life cycle and fatigue strength because specimens experienced failure at number of cycle 19 with fatigue stress 2.36 MPa.

Fussy Assessment of Fatigue Strength of Spot-Welded Structures

2012 ◽  
Vol 562-564 ◽  
pp. 2030-2033
Author(s):  
Yu Xin Yao ◽  
Chun Yuan Shi
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Standard Specimen ◽  
Point Of View ◽  
Fuzzy Mathematics ◽  
Welded Structures ◽  
Coupling Relationship ◽  
Welded Structure ◽  
Assessment Result ◽  
Spot Welded

From the point of view of the objective and scientific design of spot-welded structures, each factor that influences the fatigue strength of the spot-welded structure is quantitatively analyzed using fuzzy mathematics. The weighing coefficient is calculated based on the contribution of each factor and their coupling relationship using DARE method. All the influencing factors are divided to two levels, and quantitative assessment result is obtained. Finally, the fatigue life curve of the spot-welded structure is predicted with the utilization of the fatigue life curve of a standard specimen made of the same material.

scholarly journals Comparison of Fatigue Life Cycle of Different Aluminium Alloy AA 5083 - AA6062

2019 ◽  
pp. 283-288
Author(s):  
Sunit Yadav ◽  
Kamal Kanaujia ◽  
Ravi Shukla
Keyword(s):  
Wear Resistance ◽  
Fatigue Crack ◽  
Life Cycle ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Comparative Study ◽  
Aluminium Alloy ◽  
Fatigue Testing ◽  
Mode I ◽  
Loading Mode

Fatigue failure is one of the main reasons for the mechanical failure in engineering materials. To improve the fatigue strength of the material one of the most used method is surface treatment of the materials in which hardness, wear resistance and aesthetics is improved. In this paper a comparative study of fatigue of two different aluminium alloy [AA 5083-AA6062] was conducted. CT specimen of both the alloys was formed as per ASTM-E647 Standard. The result shows that the fatigue life of AA5083 greater than AA6062. In this paper fracture that occur in material during fatigue testing and effect of fatigue life on material is studied. The main purpose of the research presented herein was to study the fatigue crack propagation under loading mode I.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

G0301104 Influence of Variation of Nugget Diameter and Spot Welding Location on Fatigue Life of Spot Welded Joint

2015 ◽  
Vol 2015 (0) ◽  
pp. _G0301104--_G0301104-
Author(s):  
Masaki WASHIO ◽  
Chihiro TAKATUSUKA ◽  
Noboru TOMIOKA ◽  
Akifumi OKABE
Keyword(s):  
Fatigue Life ◽  
Spot Welding ◽  
Welded Joint ◽  
Nugget Diameter ◽  
Spot Welded

scholarly journals Fatigue improvement of welded elements by ultrasonic impact treatment

2020 ◽  
Vol 65 (4) ◽  
pp. 179-190
Author(s):  
Yuir Kudryavtsev
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Large Scale ◽  
Fatigue Testing ◽  
Fatigue Improvement ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of tensile residual stresses and introducing of compressive residual stresses into surface layers of a material. The secondary factors in fatigue improvement by UIT/UP are decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. Fatigue testing of welded specimens showed that UIT/UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UIT/UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The results of fatigue testing of large-scale welded specimens in as-welded condition and after application of UIT/UP are considered in this paper. It is shown that UIT/UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

scholarly journals Design Implications and Opportunities of Considering Fatigue Strength, Manufacturing Variations and Predictive LCC in Welds

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1527
Author(s):  
Mathilda Karlsson Hagnell ◽  
Mansoor Khurshid ◽  
Malin Åkermo ◽  
Zuheir Barsoum
Keyword(s):  
Life Cycle ◽  
Fatigue Strength ◽  
Life Cycle Cost ◽  
Design Stage ◽  
Direct Result ◽  
Welded Structures ◽  
Early Design Stage ◽  
Repair Costs ◽  
Welded Structure ◽  
Cost Reductions

Fatigue strength dictates life and cost of welded structures and is often a direct result of initial manufacturing variations and defects. This paper addresses this coupling through proposing and applying the methodology of predictive life-cycle costing (PLCC) to evaluate a welded structure exhibiting manufacturing-induced variations in penetration depth. It is found that if a full-width crack is a fact, a 50% thicker design can result in life-cycle cost reductions of 60% due to reduced repair costs. The paper demonstrates the importance of incorporating manufacturing variations in an early design stage to ensure an overall minimized life-cycle cost.

Effect of Strain Rate Variation on Fatigue Life of Spot Welded Joint

2005 ◽  
Vol 297-300 ◽  
pp. 2447-2452
Author(s):  
Joon Hyuk Song ◽  
Hyu Sun Yu ◽  
Hee Yong Kang ◽  
Sung Mo Yang
Keyword(s):  
Life Cycle ◽  
Fatigue Life ◽  
Strain Rate ◽  
Welded Joint ◽  
Welding Current ◽  
Dynamic Strain ◽  
Rate Variation ◽  
Welding Condition ◽  
Rate Region ◽  
Spot Welded

Resistance spot welding is used extensively to fasten sheet for automotive applications. In many components, these welds should maintain their integrity under severe loading conditions. However fatigue strength of the spot welded joint is considerably lower than base metal due to stress concentration at the nugget edge, and is influenced by its geometrical and mechanical factors such as welding condition and etc. In this paper, it is estimated that effect of strain rate variation on fatigue life of spot welded joint. The analytical method proposed to overcome above difficult using lethargy coefficient concept for evaluating the fatigue life cycle of spot welded joint. The reliability of the life cycle is completed by comparing with the life cycle obtained by fatigue test for the specimen with the welding current. And the above procedure is numerically extended to get the life of dynamic strain rate region.

Fatigue Improvement of Welded Elements and Structures by Ultrasonic Peening

2013 ◽  
Author(s):  
Yuri Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Fatigue Improvement ◽  
Surface Layers ◽  
Ultrasonic Peening ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UP is achieved mainly by relieving of tensile residual stresses and introducing of compressive residual stresses into surface layers of a material. The secondary factors in fatigue improvement by UP are decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

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