Wood Debris Impact Tests at Lehigh University

These full-scale in-air impact tests were conducted to investigate the effect of contact area and contact stiffness on peak impact force and impact duration. A 19.7 ft wood utility pole with an average diameter of 9.5 in. was chosen to impact a load cell. The head-on impact tests were conducted using both large end and small end of the wood pole. The linear and nonlinear behavior of the wood pole was examined during an axial impact. The steel plate, rubber sheet and plywood sheets were used in front of the load cell to investigate the effect of contact stiffness. Three different load cells were used to change the contact area during wood pole impact tests.
The wood pole was instrumented with six strain gauges at three cross sections along the length: 6 in. from the front, in the middle, and 6 in. from the rear. At each instrumented cross section, two strain gauges were mounted on the top and bottom of the wood pole.
Accelerometers and light sensors were used to measure the impact velocity and rebound velocity. In order to provide sufficient resolution to capture accurately an impact event, data from all instrumentation (i.e., load cell, accelerometers, strain gauges, and light sensors) were recorded at 50 kHz.