[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fshL8wUx8yDCUlug6RrI-aYwKdrctEhOts_l4pNFtANs":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":19,"related":20,"source":30,"type":31},[],"2025-05-10 16:48:18",186864734,[8,9,10,11],"增大构件的几何尺寸","提高构件表面的光洁度","减小构件连结部分的圆角半径","尽量采用强度极限高的材料",{"count":13,"courseId":14,"courseImg":15,"courseName":16,"workId":17,"workName":18},6,"4ea3fcd3ddf3cd5f864c04809e252ae8","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F39329f8ae8d09237f849d6834ce360f4.png","材料力学IMOOC（15期 2025春夏）","dda6c7fadc11431bbc48cabdadf97f16","第十三单元 交变应力","可以提高构件持久极限的有效措施有如下四种答案",[21,32,35,40,50,59],{"answer":22,"createTime":5,"id":23,"options":24,"question":29,"source":30,"type":31},[],186864732,[25,26,27,28],"(a)","(b)","(c)","(d)","分别受图示四种不同交变应力作用的试件,哪种情况最先会发生疲劳破坏?\u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F0a404315221944fbdb3b48cbcfcbce31.png\">","v1",0,{"answer":33,"createTime":5,"id":6,"options":34,"question":19,"source":30,"type":31},[],[8,9,10,11],{"answer":36,"createTime":5,"id":37,"options":38,"question":39,"source":30,"type":31},[],186864735,[25,26,27,28],"图示四种交变应力,哪一种同时满足条件:r>0和σ m +σ a<0.( r: 循环特征,σ m:平均应力,σ a:应力幅 ) \u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F657efff9a6889bbcc2db108c2ae92f18.png\">",{"answer":41,"createTime":42,"id":43,"options":44,"question":49,"source":30,"type":31},[],"2025-05-10 16:48:19",186864736,[45,46,47,48],"σ-1>σ0>σb","σb>σ0>σ-1","σ0>σ-1>σb","σb>σ-1>σ0","材料在对称循环下的持久极限为σ-1,脉动循环下的持久极限为σ0,静载荷下的强度极限为σb, 它们之间的关系有如下四种答案",{"answer":51,"createTime":42,"id":52,"options":53,"question":58,"source":30,"type":31},[],186864739,[54,55,56,57],"β σ-1\u002F(n ε σ κ σ)","κ σ σ-1\u002F(n ε σ β)","ε σ κ σσ-1\u002F(n β)","ε σ β σ-1\u002F(n κ σ)","已知材料的σ-1、κ σ、ε σ、β,规定安全系数n,则构件在对称循环下的许用应力为",{"answer":60,"createTime":42,"id":61,"options":62,"question":67,"source":30,"type":31},[],186864743,[63,64,65,66],"σ-1\u002F[β σ max\u002F(ε σ κ σ)]","σ-1\u002F[κ σ σ max\u002F(ε σ β)]","σ-1\u002F(ε σ κ σ σ max\u002Fβ)","σ-1\u002F(ε σ β σ max\u002Fκ σ)","已知材料的σ-1、κ σ、ε σ、β,构件的最大应力σ max ,构件在对称循环下的疲劳工作安全系数n有四种答案"]