Method for testing and calculating residual stress of thin plate workpiece
A technology of residual stress and calculation method, applied in the direction of measuring force, measuring device, instrument, etc., can solve the problems of low measurement accuracy, inaccurate relationship between residual stress and measured strain value, and no consideration of Poisson's ratio and strain rose size, etc. Achieve the effect of rigorous mechanics theoretical basis and strong versatility
Active Publication Date: 2019-08-06
NANJING INST OF TECH
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[0006] The main problems of the above method: the relationship between the given residual stress and the measured strain value is not accurate enough, the calibration coefficient is constant, and the influence of Poisson’s ratio and rosette size is not considered, and the measurement accuracy is low
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[0090] The sample is in a two-dimensional tensile state, and the geometric dimensions of type A strain rosettes are as follows: image 3 As shown, the sample size and the pasting position of the rosette are as follows Figure 4 As shown, the material is 45 steel tempered at high temperature. Test parameters: sample thickness 1mm, calibrated residual stress σ x =100MPa, σ y =100MPa, τ xy = 0; material elastic modulus E = 210GPa, Poisson's ratio ν = 0.3; class A strain rosette, nominal value 1 / 16in, geometric dimension D = 5.13mm, R 1 = 1.77mm, R 2 =3.36mm, GL=1.59mm, GW=1.59mm, drilling diameter D 0 =2a=2mm, substituting formula (16) to get the strain transfer matrix is:
[0091]
[0092] According to the ratio D 0 / D=0.39, check Table 3 in "GB / T 31310-2014 Metal Material Residual Stress Measurement Drilling Strain Method", and use the interpolation method to obtain the calibration constant According to the formula (2), the strain transfer matrix corresponding to th...
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Abstract
The invention discloses a method for testing and calculating the residual stress of a thin plate workpiece. The method comprises: according to a principle of stress superposition, calculating a stressstate of any point P around a through hole of a thin plate workpiece in a residual stress state to obtain a stress calculation formula for the positions of three strain gauges of a strain rosette; onthe basis of a stress-strain relationship, calculating a relationship between the strains and the residual stresses of the three strain gauges in a measurement direction; acquiring a relationship between the measured strain and the residual stress based on the strains of the measurement directions of three strain gauges and an original strain; and calculating a strain transfer matrix based on measured parameters and calculating a two-dimensional residual stress value based on the measured strain. According to the invention, an analytical formula for measurement and calculation of the residualstress is provided according to the stress superposition principle based on the elastic mechanics theory and the stress-strain relationship. The mechanics theory base is rigorous; the calculation principle error is small; the calculation precision is high; and the versatility is high.
Description
technical field [0001] The invention relates to a residual stress test and calculation method of a thin-plate workpiece, which is used in the calculation process of residual stress measurement by a through-hole method, and belongs to the technical field of residual stress test. Background technique [0002] In the process of manufacturing and assembly of mechanical parts, residual stress will inevitably be generated, which will have a serious impact on the strength, stiffness, fatigue and other mechanical properties of the parts. The residual stress state of a thin plate workpiece is a two-dimensional state, which is often measured by the through-hole method. The method is to drill a through hole on the component, use the strain rosette to measure the change of the strain value caused by the stress release around the hole after drilling, and then calculate the residual stress value according to the elastic mechanics theory. The measured strain value given by the national st...
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IPC IPC(8): G01L1/20
CPCG01L1/20
Inventor 潘龙王保升徐振钦洪磊闫注文
Owner NANJING INST OF TECH