哈尔滨工业大学春季材料力学期中考试试题A英文版.docVIP

哈尔滨工业大学2008年春季材料力学期中考试试题A英文版 (Note: this midterm exam,??points in total, is worth??of your final score.) 1. Single choice questions:????????(5 questions, 3 points each, 15 points in total) 1-1.?For the abscissa??and ordinate??in the conventional stress-strain diagram, (???????). A.?both??and??take initial values;??? B.?both??and??take instant values; C.??takes initial value,??takes instant value;??? D.??takes instant value,??takes initial value. 1-2.?Suppose the magnitude of the axial deformations of bars 1 and?2 in?the truss (see Fig. 1-2) are??and, respectively. With small-deformation assumption, the horizontal displacement??and vertical displacement??of point B are (???????). A.?，;?????????? B.?，; C.?，; D.?，. ?????????? ????????Fig. 1-2??????????????????????????????????????Fig. 1-3 1-3. As shown in Fig. 1-3, two cubic elements of the same material are subjected to two stress states, it can be concluded that their?(???????) are identical. A.?elastic strain energy density;???????B.?volumetric strain energy density; C.?distortional strain energy density;???D.?maximum shear stress. 1-4. In a beam,?the?neutral axis is the intersection line of (????????). A.?the longitudinal symmetry plane and the cross-section;??? B.?the longitudinal symmetry plane and the neutral surface; C.?the cross-section and the neutral surface;???? D.?the cross-section and the top or bottom surface of the beam. 1-5. For a transverse load applied to a beam having a rectangular cross-section, at the neutral axis, (?????????). A.?the normal stress reaches maximum, while the shear stress is zero;? B.?the normal stress is zero, while the shear stress reaches maximum; C.?both the normal and shear stresses reach maximum;?? D.?both the normal and shear stresses are zero. 2.?As shown in Fig. 2, in a rigid channel having a smooth bottom surface, there are a long bar AB and a slender bar AC, both fixed at A. Bar AC passes through AB via a hole without any contact in between. A short bar CD is connect