Abstract: At present, accurate prediction of residual strength of long lifetime structure during its service period is an important and difficult problem facing the structural design engineer. A precise load-displacement curve in the process of crack growth will provide a highly effective solution to this problem. For that, based on the fracture toughness and resistance curve theories with thickness effect considered, an investigation of load-displacement curve for a plate with growing crack is made from both theoretical and experimental aspects. An expression is given by the Castigliano’s theorem to show the relation between the external loads and the deflection on the midpoint of specimen with a stationary crack. The fracture toughness and resistance curve theories with thickness effect considered are introduced to educe the analytic closed form solution to load-displacement curve at the midpoint of specimen during crack growth. A few experiments of crack growth are also performed under monotonously quasi-static loading. The experimental data are basically consistent with the results from the analytical closed form solution, which confirms the validity of this analytical closed form solution sufficiently.

Key words: Analytical closed form solution, Crack growth, Load-displacement curve, Thickness effect