Browse Publications Technical Papers 2013-01-1438

Analysis of Damage Caused to Vehicle Body Panels by Impacting Hail and Various Tools and Objects 2013-01-1438

On the 25th December 2011 there was a hail storm in the state of Victoria, Australia, which caused approximately AU$712 million worth of damage. Some of this damage was caused to passenger vehicles. The authors conducted a number of inspections of hail-damaged vehicles as a result of insurance claims being disputed or rejected on the basis that some, or all, of the alleged hail damage was not created by hail but instead created intentionally by the vehicles' owners with the use of different tools and/or objects. As a result of the inspections and investigations of potentially fraudulent claims, the authors conducted a total of 119 tests designed to replicate damage caused to vehicle body panels by impacting hail and to recreate claimed hail damage by using tools and other objects. To do so, the authors created two sizes of hail: Ø20 mm and Ø40 mm hail. A total of 15 impact tests were conducted with Ø20 mm hail. The impact speed for the Ø20 mm hail varied between 75 km/h and 144 km/h, with the average being 113 km/h. A total of 50 impact tests were conducted with Ø40 mm hail. The impact speed for the Ø40 mm hail varied between 66 km/h and 133 km/h, with the average being 101 km/h.
The testing impact speeds were generally higher than the terminal velocities of the corresponding hail, so the damage observed is expected to be an over estimation of the actual damage caused by hail.
The hail was projected at the test vehicle using a purpose-built projectile launching device that used a sling-like mechanism to project hail in a horizontal direction at a test vehicle. The test vehicle was a white-colored 2001 model Holden Commodore with non-metallic paint. The body panels tested were: bonnet, roof, boot, all four doors, the vehicle pillars and cant rail. High speed cameras were used to determine the impact speed of the hail. Damage was photographed and recorded. In addition to impacting the vehicle with hail, a number of different tools and objects were used to recreate man-made damage. Tools and objects used were: claw hammer (conventional), welding hammer, ball-peen hammer, mason hammer, lead ball sink in a sock, golf ball in a sock, ratchet, breaker bar, crowbar and center punch. The conducted tests revealed the following findings: 1. hail impacting the vehicle body panels will not scratch or mark the paint but the paint may chip if hail impacts the vehicle near a fold or edge of a panel; 2. dents caused by hail will cause the light to move smoothly and continuously across the dent and the light will not "break" or crease; 3. where dents were caused by tools and objects the light will crease into multiple (two or more) distinct areas as it passes over the dent; 4. scratches and/or markings in the paint were identified on dents caused by tools and objects; 5. folds and curves on the panels did not affect the size of the dent caused to the panel; using the same tool and force to impact two different body panels (A-pillar and roof) resulted in dents that were very similar in physical appearance; 6. for the same impact speed the larger Ø40 mm hail caused more damage than the Ø20 mm hail; and 7. for the same size hail the higher impact speed hail caused more damage.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 40% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.