Headform Impact Testing of Plastic Glazing Materials 930741
The primary objective of this study was to compare the safety performance of two different plastic glazing materials to that of tempered glass in a moveable window application. A headform impact test method was used to determine if the use of plastic glazing materials offers the potential to reduce the risk of head injuries and fatalities inside impact collisions. These tests were conducted to simulate the dummy head velocity as it penetrates the side glazing area during Federal Motor Vehicle Safety Standard (FMVSS) 214 full-scale, side impact, crash testing. The two plastic glazing materials tested were an abrasion resistant (AR) coated copolymer of methyl methacrylate and N-methyl glutarimide (i.e., acrylic-imide or PMMI), and a polycarbonate (PC). Each of these window materials was evaluated in the driver's door of a Pontiac 6000 vehicle. The safety performance of these glazing materials was evaluated in each of the three categories: lacerations, head injuries due to contact, and containment.
None of the materials tested resulted in lacerations which penetrated through the outer layer of chamois. This result indicates that each of the materials offered acceptable laceration characteristics.
Head injury criteria (HIC) and 3 millisecond Clip values were used to assess the potential for head injuries due to contact forces. The highest HIC value measured was 262, which is much lower than the 1000 limit specified for FMVSS 208 frontal impacts. Additionally, the highest 3 ms Clip value measured was 55 g which is well below the 80 g limit specified for FMVSS 201. Therefore, the potential for head injuries due to contact is considered unlikely for each of the glazing materials.
The test windows offered total containment at the following headform impact velocities: PMMI at 26 km/h (16 mph), PC at 17.5 km/h (11 mph), and tempered glass at 14 km/h (8.7 mph). The category of containment revealed the largest differentiation between these glazing materials and showed that PMMI offered total containment at much higher headform impact velocities compared to polycarbonate, followed by tempered glass.