Glued-laminated beams with holes Part 1: Stress investigations

This paper investigates the influence of holes to stresses in glued-laminat ed beams taking into account the orthotropic material. The specifications i n DIN 1052 do not tolerate even small holes without additional strengthenin g. An analytical solution of the stress concentration at the border of an e lliptical hole for different loads is calculated using formulations of Lekh nitskii und Savin. Calculating the stresses in the area surrounding the hol e using the finite element method verifies the analytical solution and conf irms that the highest stresses appear at the border of the hole. Those stre ss peaks strain only a small volume, so that a criterion of failure based o n those stress peaks seems to be meaningless.