Chapter 3 – Normal Force, Shear Force, Bending Moment and Torsion

Publisher Summary This chapter examines the different types of loads to which a structural member may be subjected and determines corresponding internal force distributions. Structural members may be subjected to complex loading systems apparently comprised of several different types of loads. The complex systems consist of a maximum of four basic load types—axial loads, shear loads, bending moments, and torsion. Axial loads are applied along the longitudinal or centroidal axis of a structural member, shear loads act perpendicularly to the axis of a structural member, pure bending moments arise through the application of other types of loads to adjacent structural members. The chapter concludes with the discussion of the principle of superposition—an extremely useful principle in the analysis of linearly elastic structures. The principle states that if the displacements at all points in an elastic body are proportional to the forces producing them, the effect on such a body of a number of forces acting simultaneously is the sum of the effects of the forces applied separately.