Due to the particularity of welding processes, the mechanical properties of welded joint materials, especially the yield strength, are unevenly distributed, and there are also a large number of micro cracks, which seriously affects the safety performance of welded joints. In this study, to analyze the effect of the uneven distribution of yield strength on the crack propagation path of welded joints, other mechanical properties and residual stresses of welded joints are ignored. In the ABAQUS 6.14 finite element software, the user-defined field (USDFLD) subroutine is used to define the unevenly distributed yield strength, and extended finite element (XFEM) is used to simulate crack propagation. In addition, the static crack finite element model of the welded joint model is established according to the crack propagation path, which is given the static crack model constant stress intensity factor load, and the influence of an uneven yield strength distribution on mechanical field is analyzed. The results show that the crack length of welded joints as well as the plastic deformation range of the crack tip in high stress areas can be reduced with the increase of yield strength along the crack propagation direction. Moreover, the crack deflects to the low yield strength side. This study provides an analytical reference for the crack path prediction of welded joints.
Stiffness evaluation can improve the reliability and safety of combined machinery, which is often used to evaluate the performance of combined machinery. In order to study the stiffness evaluation method and rapid matching of mechanical composite structure, the composite machinery composed of high-power diesel is taken as the research object. The results show that the error between test mode and calculation mode is no more than 10%, indicating the reliability of finite element simulation model; two characterization methods of static stiffness and dynamic stiffness are determined, and the analysis methods of two characterization methods of combined machinery are discussed one by one. Taking the combined machinery of body, main bearing cap and oil pan as the research object, the overall stiffness characterization data of three parts are obtained one by one; finally, the principles of mechanical combination Stiffness Evaluation and rapid matching are summarized. This study provides a reference for Stiffness Evaluation and rapid matching of combined mechanical structures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.