Constitutive steady-state creep equations are proposed for orthotropic materials with different tensile and compressive resistances. The resistances are described using lower functions with different exponents for tension and compression. Equations are written for tension, shear, and plane stress problems. The model is used to solve the problem of torsion by a constant moment at a temperature T = 200°C for annular cross-section rods cut from a plate of AK4-1 transversely isotropic alloy in the normal direction to the plate and in the longitudinal direction. Constitutive equations for torsion are derived. Values of model parameters were obtained in experiments on uniaxial tension and compression of solid circular specimens cut in various directions. An analytical solution for the rate of torsion angle of a circular cross-section rod cut normal to the plate was obtained for the same exponent in tension and compression. For a rod cut in the longitudinal direction, an upper estimate of the torsion angle rate was obtained. The calculated results are in satisfactory agreement with experimental data.

中文翻译：

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蠕变条件下具有不同拉伸和压缩特性的正交各向异性材料的本构方程的构建

提出了具有不同拉伸和压缩阻力的正交各向异性材料的本构稳态蠕变方程。使用具有不同拉伸和压缩指数的较低函数来描述阻力。方程式是为张力、剪切和平面应力问题编写的。该模型用于求解在温度 T = 200°C 下的恒定力矩扭转问题，对于从 AK4-1 横向各向同性合金板切下的环形截面杆，在板法向和纵向方向。推导出扭转的本构方程。模型参数值是通过对不同方向切割的实心圆形试样进行单轴拉伸和压缩实验获得的。对于相同的拉伸和压缩指数，获得了垂直于板切割的圆形截面杆的扭转角速率的解析解。对于沿纵向切割的杆，获得了扭转角速率的上限估计值。计算结果与实验数据吻合较好。