Determination method of material's uniaxial constitutive relation through biconical indentation prediction

Abstract

The invention discloses a determination method of a material's uniaxial constitutive relation through biconical indentation prediction. By the use of two different diamond cone indenters (shaped as a cone or a right square pyramid), a smooth material's surface undergoes quasi-static indentation loading so as to obtain a continuous loading P-depth h curve; loading curvature C is obtained through the curve loading section; and through simple treatment, the material's uniaxial constitutive relation is predicted. By the method, the defect that existing cone indentation technology requires long-range finite element calculation and depends on multistage regression fitting to obtain complex numerical relationship and the like is overcome, and harsh technological requirements for solution to constitutive relation in the prior art are avoided. The method of the invention can be used in mechanical effects analysis of material's constitutive relation and relevant factors under loading conditions such as creep deformation, impact and the like. The invention is of great significance for acquisition of uniaxial mechanical properties of materials with a small structure or a welding structure widely existing in key projects such as micro electro mechanical system, aerospace, nuclear power, high-speed railway, oil and gas transportation, biomedical engineering and the like.

Description

technical field [0001] The invention relates to the testing of mechanical properties of materials, especially the field of testing the uniaxial constitutive relationship of in-service advanced engineering structure materials. Background technique [0002] The uniaxial constitutive relation (that is, the uniaxial stress-strain relation) is an important "link" connecting materials and mechanics, and plays an important role in the design and safety evaluation of engineering components. The usual way to obtain the uniaxial constitutive relationship of materials is to cut out standard tensile specimens with larger dimensions from engineering components or parent materials and then conduct tensile tests in the laboratory. Although this method is widely accepted and adopted, with the wide application of small-scale components and the increasing demand for on-site non-destructive testing of structural integrity evaluation for the performance of structural materials in service, it is...

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Problems solved by technology

This method also needs the loading and unloading sections of the P-h curve. On the one hand, it lacks sufficient theoretical basis. On the other hand, it is difficult to obtain a general law for this complex numerical relationship, and the solution formula can only be obtained for a specific angle. Therefore, in the actual test There are restrictions on promotion and application

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