CWA 16799:2014

Validation of computational solid mechanics models CWA 16799:2014

Scope

1.1. This CEN Workshop Agreement (CWA) builds on the research outputs of two completed projects from the European Commission's Framework Programmes FP5 and FP7 with the aim of supporting their implementation in engineering industry and the related research community. The FP5 project SPOTS (Standardisation Project for Optical Techniques of Strain measurement) led to a unified calibration methodology for all optical systems capable of measuring strain fields on planar surfaces of engineering components subject to static and pseudo-static loading12-14. The SPOTS project provided an initial step in the process of validating computational solid mechanics models by creating a route for providing high quality data from experiments which is a pre-requisite in the validation process.
1.2. The FP7 project ADVISE extended the research outputs from SPOTS in two important areas, i.e. developing an efficient quantitative method of comparing very large datasets16,21 based on image decomposition and extending the calibration methodology to include dynamic and out-of-plane loading of engineering components.
1.3. This CWA includes both a protocol for validation of computational solid mechanics models using data-fields from calibrated instruments and a methodology for the calibration of optical systems for measurement of displacement and strain fields in static and dynamic loading. These procedures provide a general approach to the validation of computational solid mechanics models used in engineering design and the evaluation of structural integrity.
1.4. This CWA exploits a number of very powerful optical measurement techniques for acquiring displacement and strain data in engineering components subject to service loads , of which digital image correlation is becoming ubiquitous. These techniques generate high-density maps of displacement and strain containing of the order of 105 to 106 data values per view, which with careful experimental design could cover the majority of the surface of an engineering component. This CWA provides a procedure for the quantitative comparison of such data with corresponding data generated by engineering simulations based on computational solid mechanics models.
1.5. This CWA proposes the use of image decomposition to allow displacement and strain fields to be represented by feature vectors, which are invariant to rotation, scale and translation, and allow enormous data compression while preserving all of the relevant information21. A validation protocol is described, based on this data compression, that is efficient to apply, takes into account uncertainties, and gives a quantitative measure of the level of agreement between the datasets from experiment and simulation16.
1.6. It is not the intention that this CWA should provide a definitive or prescriptive methodology for the validation of a computational solid mechanics model. Instead, an objective criterion and a set of associated tools are provided that can be incorporated into a plan or strategy for verification and validation, which is appropriate to the model and its intended uses. The ASME Guide for Verification and Validation in Computational Solid Mechanics4 provides further guidance on such plans and strategies, so that the procedures described here can be seen as complementary to the ASME guide.