Impact crash and simulation of timber beams

As part of a national research program for alternative timber guard-rail systems tests have been conducted to gain knowledge about the impact strength of timber. In particular the difference between the standard bending and impact bending strength is of interest as well as the difference in behaviour between a number of wood species. Former research showed contradicting test results in that strength increases with loading speed in one test programme and the opposite in another test programme. Tests were carried out on three selected wood species and three temperature treated wood species. Three point impact bending tests were performed with a loading speed of 7rnIs. A high speed camera was used to determine the time of failure. Computer simulations were used to determine the actual bending moment at the time of failure as literature showed other methods to be inadequate. Peculiar impulse transmitting effect were detected by the high-speed camera (9000 imagesls. It was concluded that the impact behaviour is wood species and grade dependent. Some wood species didn't show any significant bending strength reduction for others the reduction was dramatic.