AWS A9.5:2013 pdf download.Guide for Verification and Validation in Computation Weld Mechanics
1.1 Scope. This guide introduces computational weld mechanics methodology through an overview of the current technology. It presents current practices for heat transfer, microstructure, residual stress, and distortion calculations. In addition, a framework for developing verification and validation (V&V) procedures for these models is presented through an example related to the prediction of thermo-mechanical conditions. This document establishes the foundation for future V&V operations to allow for other emerging computational weld mechanics tools.
1.1.1 Preface. Computational models have been used routinely to great advantage for more than three decades. This technology has been used in many industries to analyze and assist in the design of many items. From architecture to telecommunications, computational analyses (structural to thermal to fuid) have been used to develop objects from the most complex to commonplace everyday items. Numerical analysis has given engineers the capability to make products better, safer, and more functional with less development costs. The growth in the use of computational models shows that commercial industries have confidence in the accuracy of the codes to reduce costs and delivery times while improving quality. In manufacturing, computational solid mechanics (CSM) and computational fluid mechanics (CFM) have been fully adopted; yet, the use of computational weld mechanics (CWM) has not. It has been suggested that the same level of confidence in CWM analyses does not exist due to relative newness of the tools and the lack of experience in their use. In comparison CWM is quite complex involving a coupled phenomena of thermal and nonlinear, transient structural analyses.Information regarding material responses due to thermal inputs, microstructure evolution, and to stresses and strains are needed to perform this type of analysis. It is for these reasons that CWM has emerged about two decades later than CSM.
The process to develop confidence in computational modeling can be expedited by a process called verification and validation (V &V). Verification testing ensures that a computational code solves the mathematical state equations that describe the phenomenon with sufficient accuracy, robustness, and reliability. V alidation tests that a particular computa-tional model predicts a particular event with accuracy and reliability. Such V&V has been developed for computational solid mechanics [1]' with Figure 1 ilustrating a typical methodology used to develop V&V documents for creating mod-els throughout the design process. This approach can be applied to CWM as well. In welding, the relevant phenomenon might be distortion, residual stress, microstructure, or risk of in-service failure. Once through this process, a computa-tional model can be used repeatedly without physical experimentations with confidence that the output will be accurate and reliable.AWS A9.5 pdf download.