不同拉压特性的双层厚壁圆筒极限承载力解答

采用统一强度理论并考虑材料拉伸与压缩弹性模量的差异性，建立均匀内压作用下双层厚壁圆筒的应力表达式，获得了其内压相应的弹性极限解答、塑性极限解答，并分析拉压强度比、拉压模量系数、统一强度理论参数、半径比及分层半径对弹性、塑性极限内压的影响规律．研究结果表明：弹性、塑性极限内压随拉压强度比的增加而减小，但随统一强度理论参数、半径比的增加而增大；弹性极限内压随分层半径的增加呈现先增大后减小变化，随拉压模量系数的增加而一直减小；塑性极限内压与拉压模量系数、分层半径无关．应用于实际工程时，可根据所得结果选择合理的壁厚及分层半径，再根据材料特性确定其他参数，以便更加准确地计算结构的受力状况．

Solution of Ultimate Bearing Capacity for a Double-Layered Thick-Walled Cylinder with Different Tension and Compression Characteristics

On the basis of the unified strength theory, stress formulations of a double-layered thick-walled cylinder with uniform internal pressure were derived by considering different material elastic moduli under tension and compression. Then, elastic and plastic limit solutions of uniform internal pressure were obtained. Finally, influences of the tensile-compressive strength ratio, the tension-compression modulus coefficient, the unified strength theory parameter and the radius ratio as well as the layered radius on the elastic and plastic limit internal pressures were discussed. It is found herein that the elastic and plastic limit internal pressures decrease with the increase of the tensile-compressive strength ratio, but increase with the increase of the unified strength theory parameter and the radius ratio. With the increase of the layered radius, the elastic limit internal pressure increases first and then decreases; meanwhile, the elastic limit internal pressure decreases with an increasing tension-compression modulus coefficient. The plastic limit internal pressure is independent of the tension-compression modulus coefficient and the layered radius. For practical engineering applications, reasonable wall thicknesses and layered radii can be selected using the obtained results, and other parameters can be determined from the material properties, to more accurately calculate the structural stress conditions.