[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fLyL2I9yMeWKvoc3rGfc9VaBwiP1Ul15SMNSMz3vuvsg":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":19,"related":20,"source":31,"type":32},[],"2023-10-18 07:31:17",100433496,[8,9,10,11],"0.24","-0.24","-4.17","4.17",{"count":13,"courseId":14,"courseImg":15,"courseName":16,"workId":17,"workName":18},12,"49d3efb62406e11f41a6865232264480","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F90262ba8150937310055f9146e61feaa.png","机械设计","94e90704214943f3a1f0b626988fa0e9","","发动机连杆横截面上的应力变化规律中最大应力为31.2 N\u002Fmm2,最小应力为-130 N\u002Fmm2,则该变应力的应力比r为",[21,33,36,45,55,63,72,81,90,98],{"answer":22,"createTime":23,"id":24,"options":25,"question":30,"source":31,"type":32},[],"2024-11-04 20:22:00",100433495,[26,27,28,29],"变应力是由变载荷产生,也可能由静载荷产生","变应力是由静载荷产生","静载荷不能产生变应力","变应力只能由变载荷产生","下列四种叙述中 是正确的","v1",0,{"answer":34,"createTime":5,"id":6,"options":35,"question":19,"source":31,"type":32},[],[8,9,10,11],{"answer":37,"createTime":23,"id":38,"options":39,"question":44,"source":31,"type":32},[],100433497,[40,41,42,43],"三个","一个","两个","四个","变应力特性σmax、σmin、σm、σa及r等五个参数中的任意 来描述",{"answer":46,"createTime":47,"id":48,"options":49,"question":54,"source":31,"type":32},[],"2024-09-23 23:11:30",100433499,[50,51,52,53],"\u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F394834ed29694f9a6bdf21ac772442d2.png\">","\u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F43da3583b7824c58e4356d97b2aed695.png\">","\u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F9f171cc86464748425c383e77e46f31f.png\">","\u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F6d42d52eb0195db248debbc7c518883d.png\">","机械零件的强度条件可以写成",{"answer":56,"createTime":47,"id":57,"options":58,"question":62,"source":31,"type":32},[],100433500,[59,60,61],"不足","刚好满足要求","足够","一直径d=18mm的等截面直杆, 杆长为800mm,受静拉力F=36kN,杆材料的屈服点σs=270Mpa, 取许用安全系数[S]σ=1.8, 则该杆的强度",{"answer":64,"createTime":23,"id":65,"options":66,"question":71,"source":31,"type":32},[],100433501,[67,68,69,70],"屈服点","强度极限","弹性极限","疲劳极限","在进行疲劳强度计算时,其极限应力应为材料的",{"answer":73,"createTime":47,"id":74,"options":75,"question":80,"source":31,"type":32},[],100433502,[76,77,78,79],"539","135","175","417","45钢的持久疲劳极限σ-1=270Mpa,设疲劳曲线方程的幂指数m=9,应力循环基数N0=5×106次,当实际应力循环次数N=104次时,有限寿命疲劳极限为 Mpa",{"answer":82,"createTime":23,"id":83,"options":84,"question":89,"source":31,"type":32},[],100433503,[85,86,87,88],"零件的材料、热处理方法、绝对尺寸","零件的表面状态、绝对尺寸、应力集中","零件的应力循环特性、应力集中、加载状态","零件的应力集中、加工方法、过载","影响零件疲劳强度的综合影响系数Kσ与 等因素有关",{"answer":91,"createTime":23,"id":92,"options":93,"question":97,"source":31,"type":32},[],100433504,[94,95,96],"降低","不变","增高","零件表面经淬火、渗氮、喷丸、滚子碾压等处理后,其疲劳强度",{"answer":99,"createTime":23,"id":100,"options":101,"question":106,"source":31,"type":32},[],100433505,[102,103,104,105],"脉动循环变应力","不对称循环变应力","静应力","对称循环变应力","在图示设计零件的σm-σa极限应力简图中,如工作应力点M所在的0N线与横轴间夹角为450,则该零件受的是"]