New method of determination of spot welding-adhesive joint fatigue life using full field strain evolution

3rd International Conference on Competitive Materials and Technology Processes

Sadowski, T.^1 ; Kne, M.^2

Lublin University of Technology, Department of Solid Mechanics, Lublin, Poland^1

Lublin University of Technology, Civil Engineering Laboratory, Lublin, Poland^2

关键词: Complicated structures;    Fatigue loadings;    Fatigue parameter;    Fatigue response;    Standard materials;    Statistical post processing;    Strain evolution;    Structural elements;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/123/1/012014/pdf
DOI  :  10.1088/1757-899X/123/1/012014

来源: IOP

【 摘 要 】

Fatigue tests were conducted since more than two hundred years ago. Despite this long period, as fatigue phenomena are very complex, assessment of fatigue response of standard materials or composites still requires a long time. Quite precise way to estimate fatigue parameters is to test at least 30 standardized specimens for the analysed material and further statistical post processing is required. In case of structural elements analysis like hybrid joints (Figure 1), the situation is much more complex as more factors influence the fatigue load capacity due to much more complicated structure of the joint in comparison to standard materials specimen, i.e. occurrence of: welded hot spots or rivets, adhesive layers, local notches creating the stress concentrations, etc. In order to shorten testing time some rapid methods are known: Locati's method [1] - step by step load increments up to failure, Prot's method [2] - constant increase of the load amplitude up to failure; Lehr's method [2] - seeking for the point during regular fatigue loading when an increase of temperature or strains become non-linear. The present article proposes new method of the fatigue response assessment - combination of the Locati's and Lehr's method.