Ball indentation characterization method for Mullins effect parameters

Abstract

The invention discloses a ball indentation characterization method for Mullins effect parameters, and belongs to the technical field of indentation experiments. The method comprises the following steps of: firstly, introducing a dimensionless function into a ball indentation experiment to establish a relationship among physical quantities in the indentation experiment; secondly, performing calculation according to a finite element model containing a Mullins effect to obtain display expression of the relationship; then carrying out an indentation experiment to obtain a load-displacement curve of an actual material; and finally, carrying out inversion according to the display expression of the dimensionless function and the load-displacement curve obtained by the indentation experiment to obtain Mullins effect parameters of the material. According to the characterization method disclosed by the invention, the stress softening mechanical property of the material can be quickly, in-situ, multi-scale and locally characterized by utilizing the ball indentation experiment, so that the complexity of a traditional tensile compression experiment is reduced, and the accuracy of the obtained Mullins effect parameter is correspondingly improved.

Description

technical field [0001] The invention belongs to the technical field of indentation experiments, and in particular relates to a Mullins effect characterization method for polymer materials. Background technique [0002] Indentation is a depth-dependent testing technique derived from the hardness scratch test developed by mineralogists in the mid-18th century and subsequently used to measure the hardness of metals. The indentation test uses the indenter to indent the material to be tested, and obtains the relevant mechanical properties by analyzing the indentation load-indentation depth curve, which is widely used in the mechanical characterization of linear elastic, plastic and viscoelastic properties of materials at the macroscopic and micro-nano scales . [0003] In 1881, Hertz developed the contact theory, and the Hertz solution was also widely used in the elastic contact problem in the indentation experiment of the ball indenter. Lee and Radok extended the Hertz contact...

AI Technical Summary

Problems solved by technology

Most of the above characterizations are conventional methods such as tension and compression. In the test, samples of specific size and shape need to be prepared, and the apparent stress softening effect of the material is likely to be affected during the machining process of the sample.

In contrast, the indentation method is easier to measure, and it is easier to achieve in-situ, multi-scale and local characterization measurements, but the current work of using the indentation method to characterize the Mullins effect is relatively rare

Although the constitutive model of the Mullins effect has already been embedded in ABAQUS, there are few reports on the characterization of its constitutive parameters by the indentation method.

Images