Vol.23, No.2 2023, pp. 179–183
UDC:

Inhomogeneous beam structures of rectangular cross-section loaded in torsion are widely used in various load-bearing engineering applications. Delamination is one of the factors which have significant influence on the integrity and reliability of these beam structures. In many load-bearing structures, the inhomogeneous beams exhibit relaxation behaviour in their life-time. Therefore, this paper studies the delamination in beams under torsion considering the relaxation of stresses and its effect on the strain energy release rate. The beam has two longitudinal vertical layers. The delamination is between the layers. The free ends of the crack arms are loaded in torsion. The angles of twist are kept constant with time in order to induce relaxation behaviour. An analysis of the time-dependent compliance of the beam under torsion is performed to derive the strain energy release rate. The J-integral method is applied to verify the solution of the time-dependent strain energy release rate. The influence of various parameters on the strain energy release rate is assessed by using the derived solution.

Keywords: relaxation, inhomogeneous beam, delamination, torsion