地大17秋《材料力学》在线作业12
地大《材料力学》在线作业一一、单选题：
1.在下列说法中，（）是正确的。 (满分:4)
A.当悬臂梁只承受集中力时，梁内无弯矩
B.当悬臂梁只承受集中力偶时，梁内无剪力
C.当简支梁只承受集中力时，梁内无弯矩
D.当简支梁只承受集中力偶时，梁内无剪力
2.莫尔强度理论认为材料的破坏（） (满分:4)
A.与破坏面上的剪应力有关，与正应力无关
B.与破坏面上的正应力有关，与剪应力无关
C.与破坏面上的正应力和剪应力无关
D.与破坏面上的正应力和剪应力均有关
3.若梁的横截面具有两根对称轴，则横截面的形心和弯曲中心必位于该两对称轴的交点。 (满分:4)
A.正确
B.错误
4.对于受扭的圆轴，关于如下结论： ① 最大剪应力只出现在横截面上； ② 在横截面上和包含杆件的纵向截面上均无正应力；③ 圆轴内最大拉应力的值和最大剪应力的值相等。现有四种答案，正确的是 (满分:4)
A.②③对
B.①③对
C.①②对
D.全对
5.在横截面面积相等的条件下，（）截面杆的抗扭强度最高。 (满分:4)
A.正方形
B.矩形
C.实心圆形
D.空心圆形
6.横截面上的内力通常是（）。 (满分:4)
A.一个主矢
B.一个主矩
C.一个主矢和一个主矩
D.一个标量
7.矩形截面梁，若截面高度和宽度都增加1倍，则其强度将提高到原来的（）倍。 (满分:4)
A.2
B.4
C.8
D.16
8.分析任意实心截面形状杆件的斜弯曲时，荷载分解的方向应当是一对（） (满分:4)
A.任意正交坐标轴
B.过形心的正交坐标轴
C.过形心的水平与垂直正交坐标轴
D.形心主惯性轴
9.在冲击应力和变形实用计算的能量法中，因为不计被冲击物的质量，所以计算结果与实际情况相比，（） (满分:4)
A.冲击应力偏大，冲击变形偏小
B.冲击应力偏小，冲击变形偏大
C.冲击应力和变形均偏大
D.冲击应力和变形均偏小
10.表示扭转变形程度的量（）。 (满分:4)
A.是扭转角，不是单位扭转角
B.是单位扭转角，不是扭转角
C.是扭转角和单位扭转角
D.不是扭转，也不是单位扭转角
11.图示1/4圆截面，c点为形心，则 <IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/aac484f3.GIF\\\></IMG> (满分:4)
A.y1，z1是主惯性轴，而y，z不是
B.y，z是主惯性轴，而y1，z1不是
C.两对轴都是主惯性轴
D.两对轴都不是主惯性轴
12.一梁在集中荷载P作用下，其变形能为U，若将力P改为2P，其它条件不变，则其变形能为（）。 (满分:4)
A.2U
B.4U
C.8U
D.16U
13.铸铁试件扭转破坏是（） (满分:4)
A.沿横截面拉断
B.沿横截面剪断
C.沿45°螺旋面拉断
D.沿45°螺旋面剪断
14.如图所示的悬臂梁，为减少最大挠度，则下列方案中最佳方案是<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/2d09b808.GIF\\\></IMG> (满分:4)
A.梁长改为l/2，惯性矩改为I/8
B.梁长改为3l4，惯性矩改为I/2
C.梁长改为5l/4，惯性矩改为3I/2
D.梁长改为3l/2，惯性矩改为I/4
15.用力法求解静不定问题的正则方程，实质上是（） (满分:4)
A.静力平衡方程
B.物理方程
C.变形协调方程
D.功的互等定理
16.长度和受载形式均相同的两根悬臂梁，若其抗弯截面刚度EI相同，而截面形状不同，则两梁的（） (满分:4)
A.最大正应力相等，最大挠度不等
B.最大正应力不等，最大挠度相等
C.最大正应力和最大挠度都不等
D.最大正应力和最大挠度都相等
17.实心圆轴扭转，己知不发生屈服的极限扭矩为T0，若将其横截面积增加１倍，那么极限扭矩是 (满分:4)
A.1.414T0
B.2T0
C.2.828T0
D.4T0
18.<p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>杆件在（）变形时，其危险点的应力状态为图示应力状态。</span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\191\\\ height=\\\169\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/70b46c69-6c08-4b7e-8716-ee89ac6f72b2/200910618517229.jpg\\\ /></span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\></span></p> (满分:4)
A.<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>斜弯曲</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
B.<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>偏心拉伸</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
C.<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>拉弯组合</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
D.<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>弯扭组合</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
19.<p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>如图所示，在平板和受拉螺栓之间垫上一个垫圈，可以提高（）强度。</span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\199\\\ height=\\\148\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/493a0bdf-3c92-41cb-b939-363f13544345/2009106174637409.jpg\\\ /></span></p> (满分:4)
A.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>螺栓的拉伸</span>
B.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>螺栓的剪切</span>
C.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>螺栓的挤压</span>
D.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>平板的挤压</span>
20.桁架受力和选材分别如图A、B、C、D，从材料力学观点看，图( )较为合理。 (满分:4)
A.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/32d90bf6.GIF\\\></IMG>
B.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/9b328fc3.GIF\\\></IMG>
C.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/fa4b9cad.GIF\\\></IMG>
D.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/c1471f82.GIF\\\></IMG>
21.<p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>低碳钢的两种破坏方式如图</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>、</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>所示，其中（）。</span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\485\\\ height=\\\101\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/4a59f41d-b95c-4fcf-a51b-de79fdc6fd3c/2009106175132208.jpg\\\ /></span></p> (满分:4)
A.(a)<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为拉伸破坏，</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为扭转破坏</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
B.<span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>、</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>均为拉伸破坏</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
C.<span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为扭转破坏，</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为拉伸破坏</span>
D.<span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(a)、<span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(b)</span></span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>均为扭转破坏</span>
22.构件的强度是指( ) (满分:4)
A.在外力作用下构件抵抗变形的能力
B.在外力作用下构件保持原有平衡态的能力
C.在外力作用下构件抵抗破坏的能力
23.比较图示两梁强度和刚度，其中（b）梁由两根高为0.5h、宽度仍为b的矩形截面梁叠合而成，且相互间摩擦不计，则有<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/0f3a6816.GIF\\\></IMG> (满分:4)
A.强度相同，刚度不同
B.强度不同，刚度相同
C.强度和刚度均相同
D.强度和刚度均不相同
24.材料相同的圆杆，它们的剪切强度条件和扭转强度条件中，许用应力的意义相同，数值相等。 (满分:4)
A.正确
B.错误
25.连接件剪应力的实用计算是以假设（）为基础的。 (满分:4)
A.剪应力在剪切面上均匀分布
B.剪应力不超过材料的剪切比例极限
C.剪切面为圆形或方形
D.剪切面面积大于挤压面面积
地大《材料力学》在线作业二
一、单选题：
1.莫尔强度理论认为材料的破坏（） (满分:2.5)
A.与破坏面上的剪应力有关，与正应力无关
B.与破坏面上的正应力有关，与剪应力无关
C.与破坏面上的正应力和剪应力无关
D.与破坏面上的正应力和剪应力均有关
2.<p><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>开口薄壁圆管一端固定，一端自由，自由端受集中力</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>P</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>作用。梁的横截面和</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>p</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>力作用线如图所示，</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>C</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为截面形心，则梁的变形状态为（）</span></p><p><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\149\\\ height=\\\146\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/276c0a1b-8270-4698-9a0b-69e089b9ddb7/200910618241774.jpg\\\ /></span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span></p> (满分:2.5)
A.<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>平面弯曲</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
B.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>斜弯曲</span>
C.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>平面弯曲</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>+</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>扭转</span>
D.<span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>斜弯曲</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>+</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>扭转</span>
3.横截面上的内力通常是（）。 (满分:2.5)
A.一个主矢
B.一个主矩
C.一个主矢和一个主矩
D.一个标量
4.如图所示的两铸铁梁，材料相同，承受相同的载荷F。则当F增大时，破坏的情况是<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/b4dbbf04.GIF\\\></IMG> (满分:2.5)
A.同时破坏
B.（a）梁先坏
C.（b）梁先坏
5.<p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>低碳钢的两种破坏方式如图</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>、</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>所示，其中（）。</span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\485\\\ height=\\\101\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/4a59f41d-b95c-4fcf-a51b-de79fdc6fd3c/2009106175132208.jpg\\\ /></span></p> (满分:2.5)
A.(a)<span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为拉伸破坏，</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为扭转破坏</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
B.<span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>、</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>均为拉伸破坏</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span>
C.<span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为扭转破坏，</span><span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(b)</span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>为拉伸破坏</span>
D.<span style=\\\FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体\\\ lang=\\\EL\\\>(a)、<span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(b)</span></span><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>均为扭转破坏</span>
6.两端铰支细长压杆，若在其长度的一般处加一活动铰支座，则欧拉临界压力是原来的（）倍 (满分:2.5)
A.1/4
B.1/2
C.2
D.4
7.在材料相同的条件下，随着柔度的增大（） (满分:2.5)
A.细长杆的临界应力是减小的，中长杆不是
B.中长杆的临界应力是减小的，细长杆不是
C.细长杆和中长杆的临界应力均是减小的
D.细长杆和中长杆的临界应力均不是减小的
8.长度和受载形式均相同的两根悬臂梁，若其抗弯截面刚度EI相同，而截面形状不同，则两梁的（） (满分:2.5)
A.最大正应力相等，最大挠度不等
B.最大正应力不等，最大挠度相等
C.最大正应力和最大挠度都不等
D.最大正应力和最大挠度都相等
9.桁架受力和选材分别如图A、B、C、D，从材料力学观点看，图( )较为合理。 (满分:2.5)
A.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/32d90bf6.GIF\\\></IMG>
B.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/9b328fc3.GIF\\\></IMG>
C.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/fa4b9cad.GIF\\\></IMG>
D.<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/c1471f82.GIF\\\></IMG>
10.结构的静不定次数等于（） (满分:2.5)
A.未知力的数目
B.支座反力的数目
C.未知力数目与独立平衡方程数目的差数
D.支座反力数目与独立平衡方程数目的差数
11.图所示，铸铁梁有（A），（B），（C）和（D）四种截面形状可以供选取择，根据正应力强度，采用（ ）图的截面形状较合理。<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/e913de79.GIF\\\></IMG> (满分:2.5)
A.A
B.B
C.C
D.D
12.如图所示的悬臂梁，为减少最大挠度，则下列方案中最佳方案是<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/2d09b808.GIF\\\></IMG> (满分:2.5)
A.梁长改为l/2，惯性矩改为I/8
B.梁长改为3l4，惯性矩改为I/2
C.梁长改为5l/4，惯性矩改为3I/2
D.梁长改为3l/2，惯性矩改为I/4
13.某机器的圆轴用45号钢制成，在使用中发现弯曲刚度不够，改善抗弯刚度的有效措施是（） (满分:2.5)
A.对轴进行调质热处理
B.改用优质合金钢
C.加粗轴径
D.增加表面光洁度
14.非对称的薄臂截面梁承受横向力时，若要求梁只发生平面弯曲而不发生扭转，则横向力作用的条件是 (满分:2.5)
A.作用面与形心主惯性平面重合
B.作用面与形心主惯性平面平行
C.通过弯曲中心的任意平面
D.通过弯曲中心，平行于主惯性平面
15.<p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>与图示应力圆对应的是（）应力状态</span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\206\\\ height=\\\169\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/ff1835ea-c43a-421c-ba97-daecd473e583/200910617590257.jpg\\\ /></span></p> (满分:2.5)
A.纯剪切
B.单向
C.二向
D.三向
16.<span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>梁在集中力偶作用截面处</span> (满分:2.5)
A.<span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>M</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图无变化，</span><span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>Q</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图有突变</span>
B.<span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\><span lang=\\\EN-US\\\>M</span></span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图无变化，</span><span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>Q</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图有折角</span>
C.<span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>M</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图有突变，</span><span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>Q</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>无变化</span>
D.<span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>M</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图有突变，</span><span lang=\\\EN-US\\\ style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA\\\>Q</span><span style=\\\FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>图有折角</span>
17.铸铁试件扭转破坏是（） (满分:2.5)
A.沿横截面拉断
B.沿横截面剪断
C.沿45°螺旋面拉断
D.沿45°螺旋面剪断
18.构件的强度是指( ) (满分:2.5)
A.在外力作用下构件抵抗变形的能力
B.在外力作用下构件保持原有平衡态的能力
C.在外力作用下构件抵抗破坏的能力
19.根据均匀性假设，可认为构件的( ) 在各处相同。 (满分:2.5)
A.应力
B.应变
C.材料的弹性系数
D.位移
20.图示1/4圆截面，c点为形心，则 <IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/aac484f3.GIF\\\></IMG> (满分:2.5)
A.y1，z1是主惯性轴，而y，z不是
B.y，z是主惯性轴，而y1，z1不是
C.两对轴都是主惯性轴
D.两对轴都不是主惯性轴
21.若某低碳钢构件危险点的应力状态为近乎三向等值拉伸，进行强度校核时宜采用（）强度理论。 (满分:2.5)
A.第一
B.第二
C.第三
D.第四
22.梁发生平面弯曲时，其横截面绕（ ）旋转。 (满分:2.5)
A.梁的轴线
B.截面对称轴
C.中性轴
D.截面形心
23.材料经过冷作硬化后，其( )。 (满分:2.5)
A.弹性模量提高，塑性降低
B.弹性模量降低，塑性提高
C.比例极限提高，塑性提高
D.比例极限提高，塑性降低
24.厚壁玻璃杯因沸水倒入而发生破裂，裂纹起始于（） (满分:2.5)
A.内壁
B.外壁
C.壁厚的中间
D.内、外壁（同时）
25.比较图示两梁强度和刚度，其中（b）梁由两根高为0.5h、宽度仍为b的矩形截面梁叠合而成，且相互间摩擦不计，则有<IMG SRC=\\\http://file.open.com.cn/Lms/ItemDBAttachments/image/singleselect/ddptclx/20060408/0f3a6816.GIF\\\></IMG> (满分:2.5)
A.强度相同，刚度不同
B.强度不同，刚度相同
C.强度和刚度均相同
D.强度和刚度均不相同
26.应力是横截面上的平均内力。 (满分:2.5)
A.正确
B.错误
27.在下列条件中，（）对于变形体的虚功原理是不必要的。 (满分:2.5)
A.变形体的材料是线弹性的
B.变形体处于平衡状态
C.虚位移必须是微小的
D.虚位移必须满足位移边界条件和变形连续条件
28.一梁在集中荷载P作用下，其变形能为U，若将力P改为2P，其它条件不变，则其变形能为（）。 (满分:2.5)
A.2U
B.4U
C.8U
D.16U
29.若梁的横截面具有两根对称轴，则横截面的形心和弯曲中心必位于该两对称轴的交点。 (满分:2.5)
A.正确
B.错误
30.材料力学只限于研究等截面杆。 (满分:2.5)
A.正确
B.错误
31.一拉伸钢杆，弹性模量E=200GPa，比例极限σp=200MPa，今测得其轴向应变ε=0.0015，则横截面上的正应力（）。 (满分:2.5)
A.σ=Eε=300MPa
B.σ>300MPa
C.200MPa<σ<300MPa
D.σ<200MPa
32.<p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>在图示四个单元体的应力状态中，（）是正确的纯剪切状态。</span></p><p><span style=\\\FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EL; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\424\\\ height=\\\131\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/6618a2bb-2256-4574-81e5-391c82ce719d/2009106174954801.jpg\\\ /></span></p> (满分:2.5)
A.(A)
B.(B)
C.(C)
D.(D)
33.等截面直梁在弯曲变形时，挠曲线的曲率最大发生在（ ）处。 (满分:2.5)
A.挠度最大
B.转角最大
C.剪力最大
D.弯矩最大
34.若将受扭实心圆轴的直径增加一倍，则其刚度是原来的 (满分:2.5)
A.2倍
B.4倍
C.8倍
D.16倍
35.<p style=\\\TEXT-INDENT: -30.75pt; MARGIN-LEFT: 30.75pt; mso-list: l0 level2 lfo1; tab-stops: list 30.75pt\\\ class=\\\MsoNormal\\\><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>高宽比</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>h/b=2</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>的矩形截面梁，若将梁的横截面由竖放（图</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>(a)</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>）改为平放（图（</span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\>b</span><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\>）），则梁的最大挠度是原来的（）倍</span></p><p style=\\\TEXT-INDENT: -30.75pt; MARGIN-LEFT: 30.75pt; mso-list: l0 level2 lfo1; tab-stops: list 30.75pt\\\ class=\\\MsoNormal\\\><span style=\\\FONT-FAMILY: 宋体; mso-ansi-language: EL; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'\\\><img width=\\\203\\\ height=\\\169\\\ alt=\\\\\\ src=\\\http://file.open.com.cn/ItemDB/8639/5015620f-f602-4da1-8c94-66eb25a89a4c/2009106175831492.jpg\\\ /></span><span style=\\\mso-ansi-language: EL\\\ lang=\\\EL\\\><o:p></o:p></span></p> (满分:2.5)
A.2
B.<p>4</p>
C.6
D.8
36.在梁的正应力公式中，Ｉ为梁截面对（）的惯性矩。 (满分:2.5)
A.形心轴
B.对称轴
C.中性轴
D.形心主轴
37.在横截面面积相等的条件下，（）截面杆的抗扭强度最高。 (满分:2.5)
A.正方形
B.矩形
C.实心圆形
D.空心圆形
38.阶梯圆轴的最大切应力发生在 (满分:2.5)
A.扭矩最大的截面
B.直径最小的截面
C.单位长度扭转角最大的截面
D.不能确定
39.外力就是构件所承受的载荷。 (满分:2.5)
A.正确
B.错误
40.杆件受扭时，横截面上的最大切应力发生在距截面形心最远处。 (满分:2.5)
A.正确
B.错误
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