Eager to know about how mechanical testing is performed on composite materials? Then reading this article is a must for you.
Due to the increasing awareness of the benefits offered by composite materials, more and more applications & products are utilising them every day. As such, the demands for mechanical testing of composite structures, components and materials is skyrocketing with the developing needs for lightweight composites in the field of ground transportation, aerospace and sustainable energy projects. But in order to be used in structural applications, inhomogeneous and anisotropic materials require various mechanical tests for absolute characterisation of their properties.
The primary international standards for mechanical testing of composites are maintained by European Committee for Standardisation, ISO and ASTM. in several cases, it has been found that test methods as per different standards involve almost the same processes. However, there exist substantial differences in fixture and specimen dimensions.
The initial tests performed for determining bulk properties of composites are usually those for compression, shear and tension. For materials development and qualification, other tests are utilised to explore intricate properties and include OHT or OFC (open hole tension or compression), CAI (compression after impact), inter-laminar fracture toughness and fatigue. All of these tests are conducted over various temperatures, since materials might have had to be conditioned in different environments such as by immersion in liquids and exposure to high humidity.
One of the most in-demand areas of mechanical weld testing in Melbourne for composites is undoubtedly aerospace applications. Labs that undertake the tests have to face several challenges, the most common of which are:
The most commonly used environment for testing composites is temperature (general range: -80 to 250 degrees Celsius. There are specially designed chambers to conduct tests at high as well as low temperatures. The chambers have forced convection to heat up and systems for injecting liquid nitrogen to cool down. Prior to testing, specimens are conditioned in wet or hot conditions or by exposure to fuel, water and other hydraulic fluids. When in their conditioning medium, the materials normally take some days or even weeks for achieving equilibrium.
To conclude with, performing mechanical tests on composites is intricate and encompasses several tests, regulatory standards and different environments. Nowadays, however, grips & machines aligned effectively for testing, test software having pre-configured methods and interchangeable fixtures, have made things a lot easier.
