ABSTRACT
In the previous chapters, the structural and stress problems were solved on the basis of static equilibrium by considering the relationship between the internal forces (stresses) and the externally applied loads. The same problems can also be solved on the basis of the principle of conservation of energy by considering the energy built up within a body. The energy is stored due to the deformation in relation to the work done by the externally applied loads. In general, the principle of conservation of energy in structural and stress analysis establishes the relationships between stresses, strains or deformations, material properties and external loadings in the form of energy or work done by internal and external forces. The basic concepts of work and energy are as follows:
Unlike stresses, strains or displacement, energy or work is a scalar quantity. Simple application of an energy method is to equalise the work done by external loads and the energy stored in a deformed body, while the most powerful method that can effectively solve a complex structural and stress problem is based on the principle of virtual work.
