Device for measuring true stress and true strain of sample

Abstract

A device for measuring true stress and true strain of a sample comprises an upper chuck which is connected with the sample; an extensometer and a clamp type extensometer which are clamped on the sample; a lower chuck which is connected with the sample and a fixed device; a suspension plate which is arranged on the fixed device and is connected with the fixed device through a vertical plate; a screw rod which is arranged between the suspension plate and the fixed device; a motor which is arranged on the fixed device and connected with a first cylindrical gear, wherein the first cylindrical gearis meshed with a second cylindrical gear, the second cylindrical gear is assembled on a lead screw, and a moving device is assembled in the middle section of a lead screw and connected with the clamptype extensometer and a guide groove. The gear drives the screw rod to rotate and a moving device moves up and down; the clamp type extensometer reciprocates up and down in the direction of the guiderail, the sample is necked, the clamp type extensometer is clamped at the necking position of the sample, outputs the size change data of the sample to a computer, and draws a relation curve of realstress and real strain. The accuracy is high, the practicability is high, the operation is convenient, and the effect is good.

Description

technical field [0001] The invention belongs to the technical field of testing devices, in particular to a device for measuring real stress and real strain of a sample. Background technique [0002] In the field of engineering, the true stress and true strain values ​​calculated by using the nominal stress and nominal strain cannot accurately describe the true stress and true strain. Routinely used calculation methods of true stress and true strain (based on the measured engineering stress and engineering strain, the quantitative formula is used to calculate: σ=S(1+e), ε=ln(1+e); σ is true Stress, ε is the true strain, S is the engineering stress, and e is the engineering strain) Due to the existence of experimental factors and the defects of the method itself, the accuracy between true stress and true strain is further reduced. Contents of the invention [0003] In order to solve the above problems, the object of the present invention is to provide a measuring device for...

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Problems solved by technology

[0002] In the field of engineering, the true stress and true strain values ​​calculated by using nominal stress and nominal strain cannot accurately describe the true stress and true strain

Routinely used calculation methods of true stress and true strain (based on the measured engineering stress and engineering strain, the quantitative formula is used to calculate: σ=S(1+e), ε=ln(1+e); σ is true stress, ε is the true strain, S is the engineering stress, and e is the engineering strain) Due to the existence of experimental factors and the defects of the method itself, the accuracy between true stress and true strain is further reduced

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