Matching method for restraint degrees between actual structure and laboratory sample

Abstract

The invention relates to a matching method for restraint degrees between an actual structure and a laboratory sample. Finite element models are built for a to-be-matched structure and a matching sample according to respective characteristics, and a J-integral and a strain field of a crack tip are subjected to numerical calculation; same PEEQ (equivalent plastic strain) values are selected for the to-be-matched structure and the matching sample, and an area Apeeq of a region defined by PEEQ contour lines under different J integrals is calculated, thereby obtaining respective J-Apeeq curves; the two obtained J-Apeeq curves are drawn under a same coordinate axis to perform comparison; if the two curves coincide, it is indicated that the restraint degrees of the to-be-matched structure and the matching sample are matched; and if the two curves do not coincide, re-selecting the matching sample, and performing matching, until the curves coincide. The restraint degree of the actual structure can be matched with the laboratory sample; the transplantation of the laboratory sample to the actual structure is realized; and a technical foundation is provided for accurate structure integrity assessment. The matching of the restraint degrees among different samples, between the actual structure and the laboratory sample and between the different samples and the structure also can be realized.

Description

technical field [0001] The invention relates to a structural integrity evaluation technology, in particular to a method for matching restraint degrees between an actual structure and a laboratory sample. Background technique [0002] The fracture toughness of a material is affected by factors such as sample / structure geometry, crack size, and loading method. This effect is often referred to as the "restraint effect". The increase in restraint will lead to a decrease in the fracture toughness of the material. Accurate structural integrity assessment is based on accurate fracture toughness measurement, so in order to conduct accurate structural integrity assessment, it is necessary to investigate and measure the degree of restraint of the sample / structure. [0003] In the current structural integrity evaluation method, the safety of the actual structure is generally evaluated by the lower limit value of the fracture toughness of the material measured by the high-constraint sta...

AI Technical Summary

Problems solved by technology

However, this will bring many disadvantages: when it is used to evaluate low-constraint cracks in the actual structure, it will produce too conservative results and cause a lot of waste; When cracked, it may produce non-conservative (unsafe) results

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