Overhead Guard Physical Tests vs LS-DYNA FE Simulations

The lifting and excavating industry are not as advanced as automotive in the use of modern CAE tools in the early stages of design and development of heavy machinery. There is still a lack of confidence in the integrity of the results from FE simulations and optimisation and this becomes a barrier to the adoption of virtual prototyping for vehicle verification. R&D of Tata Steel has performed tests on two forklift truck overhead guards supplied by a major manufacturer. Based on the international standard for Falling Object Protective Structures (FOPS) as an initial input to the method of testing, the main aim of this study was to generate as much test data as possible to correlate the Finite Element (FE) simulations of two tests - a static and a dynamic test. The static test was developed to deform the overhead guard plastically in a slow controlled manner, so it would be easier to correlate the measured data to FE simulation. A dynamic test is always very difficult to correlate due to the fact that the whole test is over in less than a second and the dynamic response of the structure makes the data extremely noisy. However, this paper demonstrates that paying close attention to all of the input data for an FE model results in a close correlation between the test and the FE simulation even in highly dynamic conditions.