Impact Performance of Roofing Tiles
More than any other exterior surface a building's roof is the one that is exposed to the most impacts from weather-driven objects such as tree debris and ice. Roof tiles cracked by impacting objects will allow moisture to penetrate and decay the underlying structure resulting in costly repairs. Arbitrarily increasing the tile thickness can improve impact performance; however designers must then consider the additional weight and cost of materials inherent in this simplistic approach Impact performance at both high and low energies, need to be accurately quantified in order to optimize the design of the tiles.
We were recently asked by a supplier of synthetic roofing tiles to assist them in choosing an instrumented impact system that could be used to perform low energy tests to ascertain how much damage may occur to their products. The customer supplied us with several samples of two different styles of tiles that they manufacture.
Both our CEAST 9340 and our CEAST 9350 Impact Test Machines are capable of performing the tests that the customer wanted to do. A custom support fixture which simulates the position and way that the tiles are installed was designed and recommended to the customer. Instrumented with a 22.2kN tup, ½” hemispherical tup insert, as well as our DAS 8000 Data Acquisition System and Visual Impact software, we were able to establish the energy levels at which incipient damage begins to occur in the tiles supplied. We prevented any secondary impacts on the specimen by installing the Anti Rebound Device.
Either the 9340 or the 9350 are well suited for helping customers determine the performance characteristics of their materials when subjected to an impact event. The information gathered by doing instrumented impact testing can be used to provide the customer with a data baseline whereby they can determine how changes made in the mix of raw materials will perform in real life situations. A broader range of testing could be accomplished with the use of an environmental chamber to study impact characteristics at different temperatures as well as using different fixtures and inserts to simulate other unsupported spans and impact events.
Impact resistance is one of the most important properties for component designers to consider, as well as the most difficult to quantify. Impact resistance is a critical measure of service life and more importantly these days, it involves the perplexing problem of product safety and liability. With the combined experience of Dynatup® and CEAST, Instron® has more than 80 years experience in designing impact testing systems to simulate real-life impact conditions.
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