《哈尔滨工业大学二零一六年材力期中考试试题（英文）》.doc

(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 connected to AC at its end. A