1. Axial force --- the pressure is negative and the tension is positive
shear force --- make the rod section rotate clockwise around any point in its body to be positive
2. Calculation of truss axial force with node method:
two unknown forces can be obtained from a node equation, generally starting from the support node and proceeding in turn. For a node, if the member is removed and replaced by force along the member direction, it can be assumed that it is tensile force (if the force is negative, it means pressure). The equilibrium equations in X and Y directions are listed respectively (the forces are projected into the equilibrium equations in X and Y directions respectively): ∑ x = 0 ∑ y = 0. The specific form may be as follows: f1cosa + f2cosb + acosc = 0, f1sina + f2sinb + asinc = 0, where a represents the known force, F1 F2 is the unknown force. The unknown forces F1 and F2 can be obtained by solving the equations. The positive value is the tensile force and the negative value is the pressure
3. Surface method: the so-called cross-section method is a method to use the imaginary cross-section to cut the bar at the required position, and then use the balance equation to calculate the internal force from the external force. The steps of calculating internal force with section method are as follows: (1) cut the section where you want to calculate the internal force, suppose to cut the bar, leave the research object, and discard the other part 2) Instead, the force (i.e. the internal force to be calculated) is used to replace the effect of the abandoned part on the research object. 4. The algebraic sum of the moments of two mutually balanced forces to the same point is zero 3) Calculate and draw the force diagram of the research object, and use the balance equation to calculate the internal force from the known external force.
4. The axial force at the upper end of each column is obtained by adding the shear force at the end of the transverse frame beam, the reaction force at the end of the longitudinal frame beam (calculated according to the simply supported beam) and the axial force from the upper column; The axial force at the lower end of each column is the axial force at the upper end plus the self weight of the column.
5. The numbers are out of sight. The picture is slanted
6. According to the fact that the strain of reinforcement is equal to that of concrete support.
7. It doesn't seem to make sense.. Bending moment diagram, shear force diagram and stress diagram all have the meaning of area representation and axial diagram.. I think it's Muyou..
8. The compressive stress is negative and the tensile stress is positive
9. It's very simple. Analyze the force at point B, and calculate the sum of longitudinal force and transverse force as 0.
10.
it took a lot of time to draw. I hope it can help you
