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从入射线无负η倾角侧倾法X射线应力测定技术中的特殊几何关系出发,推导出其应力计算公式:2θ=asin~2ψ_0+bsinψ_0+c,σ_x=(Ksec~2η_0)a,τ_(xy)=(-Kcsc2η_0)b。在测出一组ψ_0角所对应的2θ值后,利用介绍的±ψ_0直线法或±ψ_0抛物线法,可以求出抛物线方程的系数a和b,从而求得测量方向上的正应力σ_x和σ_x作用面上的剪应力τ_(xy)。误差分析结果表明:这种应力计算公式以及±ψ_0直线法和±ψ_0抛物线法两种测量计算方法,完全可以满足工程测量或实验室工作的要求。由于入射线无负η倾角侧倾法一次测量可同时测得σ_x和τ_(xy),所以对试件表面上的一点只需要在二个方向上进行测量,就可确定其应力状态。在入射线无负η倾角侧倾法测量中,如用常规法或入射线有倾角侧倾法应力计算公式计算应力,往往会产生较大的系统误差。系统误差的大小主要取决于测量方向上的正应力值及此正应力作用面上的剪应力值和η。对入射线无负η倾角侧倾法应力计算公式和有关的分析,巳经用实验结果得到验证。
Based on the special geometric relationship of the X-ray stress measurement technique of the tilted X-ray with no negative incidence on the incident line, the stress formula is deduced: 2θ = asin ~ 2ψ_0 + bsinψ_0 + c, σ_x = (Ksec ~ 2η_0) a, τ_ xy) = (- Kcsc2η_0) b. After a set of 2θ values corresponding to the ψ_0 angle are measured, the coefficients a and b of the parabolic equation can be calculated using the introduced ± ψ_0 line method or ± ψ_0 parabola method to obtain the normal stress σ_x and σ_x in the measurement direction Shear stress on the active surface τ_ (xy). Error analysis results show that this stress calculation formula and ± ψ_0 line method and ± ψ_0 parabola method two measurement and calculation methods, can fully meet the engineering measurement or laboratory work requirements. Since the incident line without negative η tilt method can be measured at the same time measured σ_x and τ_ (xy), so the specimen surface only need to measure in two directions, you can determine the stress state. In the non-negative η tilt measurement of the incident line, if the stress is calculated by the conventional method or the inclined roll method of the incident line, a large systematic error often occurs. The size of the systematic error mainly depends on the normal stress in the measurement direction and the value of shear stress and η on this normal stress acting plane. The formula for calculating the stress and the related analysis of the tilted tilt method for the incident ray have been verified by the experimental results.