Engine mount quality tests

A series of tests of engine mounting brackets manufactured by Concentric (Pressed Products), part of the Concentric group, for Nissan Motor Manufacturing UK confirmed that the parts will perform satisfactorily in service. Concentric was diversified group of companies supplying components and services round the world for the end products of other manufacturers; it was acquired by Haldex in 2008

The Birmingham, UK, based company, which specialised in safety-critical pressed metal assemblies and precision welded fabrication, sent three different types of bracket to TWI for testing as part of Nissan's stipulated quality assurance programme.

Concentric was well aware of TWI's expertise and know-how in testing a range of components and structures. The tests covered static strength, durability (fatigue behaviour) and bolt loosening (loss of torque).

The first task was to manufacture and modify the jigs and fixtures needed to load the components. Two jigs were supplied by Concentric but two more were designed and made at TWI. Trials to obtain correct running conditions were followed by tests on 18 components to develop the techniques.

In static tests the brackets did not exhibit a clearly defined elastic limit, so load-versus-extension methods of determining the yield point could not be used. As an alternative, a method of hysteresis loading was adopted and proved satisfactory in strength determination.

The main test programme then encompassed a minimum of three components in each of 18 test types, i.e. a total of at least 54 tests. Brackets of the types successfully tested will soon be in service in the new Nissan range of family saloons.