Incline Impact: A Case Study

An incline impact test can be used as a shock test in lieu of a drop test in several test protocols, including ISTA Procedure 1A [1]. Some test protocols, such as ISTA Procedure 1E [2], only allow for an incline impact test and horizontal impact test. In this case study, a graph was developed for a 500-lb impact tester at Christian Brothers University (CBU) Packaging Laboratory. It determines sliding platform location on the incline for a given packaged-product weight to meet the impact velocity recommended by the International Safe Transit Association (ISTA). One station of the platform location higher than the station obtained from the graph is recommended to ensure the meeting of ISTA recommended impact velocity. It is well known that weight is not used in impact velocity of a free fall drop. However, this case study shows that weight contributes to impact velocity of an incline impact test. It contributes to the rolling friction. A heavier weight yields a smaller coefficient of rolling friction ( 𝜇𝑘 ), which results in a higher impact velocity. The coefficient of rolling friction for CBU’s incline impact tester can be computed from 𝜇𝑘 = −9 −5𝑤 + 0.1092, where w is the total weight of the sliding platform and packaged product.