The Testing Times

These grips are used to test seat belts and webbing up to 100mm thick. seat belts have interesting properties, they have to cushion the shock of a crash without injuring the passenger of the car at low speed stops. In a collision it has a precise elastic limit, meaning that it stretching slightly to diffuse the shock, goes beyond its elastic limit, becomes plastic then holding it's passenger without breaking, there is a great deal of force involved in this process (which is why these grips are rated to 100 kN ...) The testing can be quite explosive as the belt stores a great deal of energy before failing. By exerting a tensile force on the belt it is possible to see how it will behave. One of the important features of this grip is that it is self tightening. The specimen is feed through the grips in a specific manner as not to damage the belt. A damaged belt can dramatically affect its ability to protect the passenger, and once it has been stretched to it's elastic limit and ...

A flexural test tells the tester how much force a specimen can withstand in the middle when supported at a distance (or its flexibility!). This test supports the specimen between two loose fitting ‘rollers’, the distance apart of which can be set for a specific test or specimen size. Once the sample is in place the anvil can be brought down just above the specimen. A variety of tests can then be performed. The specimen can be flexed a certain number of times to judge it’s elasticity or plasticity over a given time. The specimen could be flexed until it breaks, it could be flexed for a specific time and the responding force measured. This is a Heavy Duty system, which has been designed to suite the U-Series 100 kN System . It has a travel of 400mm from centre (800mm overall) and Ø10mm rollers. This can all be recorded in the software and multiple specimens can be tested.

At first sight, one of less intricate but useful tests is compression tests. This is basically applying a force (measured in Newton’s) to the sample and measuring the effect the force has. There are a wide range of tools for doing this but in general platens are used to hold the sample and apply the force. Platens are large flat surfaces that can be used to compress a sample… The S0404 platens are big, very big. They fit on the 100 kN U-series Systems (they can apply a force of 100 kN to an object) Tinius Olsen produce… These behemoth platens are 350mm x 350mm and 35mm thick plough ground plate. I’m a big chap and I can’t lift one on my own… A brute force approach, but the feedback received through the Loadcell and Compressometer is very precise and can show how much force a sample can take and spring back or fail. The results gleaned from these tests can tell a great deal about the product under test, the 'intelligence' comes in the form of the Software, which can be use...