A scientific problem and analytical method for structure reinforcement

Beam reinforcement is reduced to mechanics behavior of structures of multilayer materials in this paper. An analytical method is presented based on Hamiltonian system. In the system, displacements and stresses are pairs of dual variables. The state vectors of the system describe directly connective conditions on the interfaces of two materials and structures so that the rule of normal and shear stresses on the interface can be revealed. Based on the criterion of lamination crack, the interface strength is determined. Results show that the lamination crack correlates highly with the ratios of material constants and geometrical parameters of structures. The result and conclusion provide a design criterion for structure reinforcement.