材料力学课堂教学软件（英文版）-范钦珊-Strength of Materials－3.pptVIP

Eccentric load：does neutral axis exit? If yes, does it pass through the center of area of cross section. Knowing that external force FP and the size of cross- section shown in the Figure, determine the normal stress at the fur angular points of the section ABED. ? Applications of the normal stress equation ? Application examples Example 5 There are two methods to solve this problem:equilibrium method and simplified method of external force system. ? Some special cases ? Applications of the normal stress equation Example 5 Solution：1.Determine the internal force components in the section Solution：2.determine the stresses in the section ? Some special cases ? Applications of the normal stress equation Example 5 Stress plane ? Some special cases ? Applications of the normal stress equation Example 5 Neutral axis ? Concept of neutral axis ? Applications of the normal stress equation Stress distribution The equation above is the normal stress distribution equation in the cross—section. According to Hooks law ? The method of normal stress analysis ? Strain and stress distribution ? Utilize the statics equations to determine undetermined constants ? The method of normal stress analysis Substituting the expression of stress with undermined constants into the three statics equations related to normal stress, ? Utilize the statics equations to determine undetermined constants ? The method of normal stress analysis From the geometry property of the cross—section,we obtain: ? Utilize the statics equations to determine undetermined constants ? The method of normal stress analysis In these equation is the static moment is the moment of inertia is the product of inertia ? Utilize the statics equations to determine undetermined constants ? The method of normal stress analysis ？ How to simplIfy the expression Sy= Sz= 0 , Iyz = 0 Assuming that the c