METHODS FOR FULL SCALE IMPACT TESTING
OF SKI SAFETY BARRIERS

Nicola Petrone1 and Francesca Ceolin2

1Departement of Mechanical Engineering, University of Padova, Italy
2DolomitiCert Laboratories, Longarone BL, Italy

KEY WORDS: ski safety barriers, impact behaviour, full scale testing.

INTRODUCTION: Aim of the study was the development of full scale test methods for the dynamic evaluation of the structural behaviour of ski safety barriers during the impact of instrumented dummies. Ski safety during competitions and generally in the skiing resorts always relies on the proper application of safety barriers such as type A, B, C nets and foam or air mattresses. The present work addresses the development of repeatable full scale test methods for a standard experimental comparative evaluation of safety barriers.

METHOD: Two types of full scale test methods were developed: (i) a 12 m tower pendulum on dry soil (Fig. 1) and (ii) a steep 110 m toboga on snow (Fig. 2). Air and foam mattresses were tested by both methods with either a fixed wall or a set of dynamic poles planted in the soil/snow. Wooden dummies of 70/82 kg mass were instrumented with triaxial accelerometers at the CoM, impacts were sampled at 50 kHz and filmed by 3 video cameras.

Figure 1. (a) Dummy for pendulum. (b) Foam mattress with poles. (c) Results for foam mattress with poles.

Figure 2. (a) Dummy for snow. (b) Foam mattress with poles. (c) Results of foam mattress with poles.

RESULTS: In pendulum tests, maximum impact speed was 56.5 km/h. The peak values recorded on foam mattresses for the resultant decelerations were greater than 20 g with the fixed wall and around 14 g with the poles; air mattresses showed lower ability of energy absorption (80%) than foam (93%) and higher tendency of the dummy to jump over the barrier. In the snow tests the maximum impact speed was 73.8 km/h but the orientation of the dummy was not consistent during the impacts. Peak resultant decelerations on fixed wall were 19 g for foam and 35.8 for air mattresses; type B nets gave 13.5 maximum peaks.

CONCLUSION: The methods proposed were able to give significant quantitative values for the comparative evaluation of different safety barriers. The tower pendulum method is suitable for the definition of a standard testing procedure.

REFERENCES

Petrone N., Pollazzon C., Morandin T., Structural behaviour of ski safety barriers during impacts of an instrumented dummy, 7th ISEAConf., Biarritz, 2-6 June 2008, Vol. 2, pp.633-642, Springer, 2008.