某材料的曲线如图，强度计算时，若取安全系数为2，那么材料的许用应力（ ） MPa。https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/ced7a16808d046e7b71fc55ce30484a1.png
举一反三
- 条件同上题强度计算时，若取安全系数为2，那么材料的许用应力[σ]=___________Mpa
- 某材料的曲线如图所示，强度计算时，若取安全系数n=2，那么材料的许用应力[σ]=200MPa。[img=283x243]180384eb0525128.png[/img]
- 在定温边界条件下，稳态、无内热源、导热系数为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/bf35cea9e03449f0b64673e21dbdde56.png" />、内外径分别为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/3323de11627a4f51bc7b1fff540dcfef.png" />和<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/675dd37c97db44a7a723838858eab505.png" />、长度为l的单层圆筒壁的导热热阻为（）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/892cb3300ea148d994377392a697acb0.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7003425fa14a44d5aadbb9040240edca.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/040ff55c3a244877a0b06faf6042f47a.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/b5d2a5ed4d644ae6b2dab35d2ed8f3e5.png" />
- 如图示并联管路，已知各支路的沿程阻力系数之比为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/6e209020d20f4543823ce6516ae8ca06.png" />，管长之比为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/50814fe028094040bc955d8e1542b6d2.png" />，且<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/40b4c6a9565b483590c5c7d607e7ed66.png" />，则两支管的流量之比<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1055534bfce6426a94682ba086a5b17e.png" />=（）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/77815369f5cd41f3a2e68b9524b454c5.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/0cd231eebe45465f941a0f614743e6d2.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7555afa5223e40bf89ca575cf7b52754.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1b06cd474b844644a6d97ad87d208e94.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d0b2bca045414236a7d1c9925a9264f2.png" />
- 外径为D、内径为d的空心圆轴，其扭转截面系数为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/af42d1bd70034c0d85f2f419a2839f22.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/2e74a84c10d14288a269b7b8def735f1.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/55aca62def3e4c9485e9b0894a63a342.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/6ed4e2143b6a4c82ad03319473bb6a3a.png" />