Application of a Finite Element Method in Welded Shell Calculation of Hydraulic Shock-Absorber

Purpose of research. The article describes application of various calculation methods of intense deformed condition of welded shell of hydraulic shock-absorbe. The purpose of the study is to find optimum calculation methods of the intense deformed state of welded structures working under pressure, providing a possibility of structure rational design at minimum material expenses with the given durability safety factor.

Methods. There are no reliable calculation methods reflecting operations of welded structures under excessive pressure. Calculation on durability of welded structures by resistance method has a number of assumptions especially for the constructions operating under excessive pressure. The assumptions are 1. hypothesis of flat sections; 2. hypothesis of monoaxial tension; 3. hypothesis of linear heating sources and limit thermal state; 4. restrictions on metal properties; 5. conditional dependence of fluidity limit on temperature. It is possible to use SolidWorks (SolidWorksSimulation application) for stress and deformation analysis in weld joints, the UGSNX program (NXNastran application), the KOMPAS-3D program (APMFEM application).

Results. Calculations by material resistance method in accordance with State Standard 14249-89 differ from calculation results in finite element methods. There is tension increase difference in calculations by finite element methods and by resistance materials method at pressure increase in the shell of hydraulic shock-absorber. The difference is nearly 50% with an internal pressure more than 11 MPas. This fact has to be considered at design of similar structures.

Conclusion. The use of various calculation methods of intense - deformation state of welded shell allows to design a product at minimum material expenses with the set durability safety factor [1].

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