【单选题】4 / 11薄壁圆筒环向应力近似公式为?Apd/(2δ)pd/(2\delta)pd/(2δ)正确B2pd/δ2pd/\delta2pd/δCpδ/(2d)p\delta/(2d)pδ/(2d)DFN/AF_N/AFN/A 且与 ppp 无关参考答案A参考解析σ=pd/(2δ)\sigma=pd/(2\delta)σ=pd/(2δ)。