AWS A9.5:2013 pdf free download

AWS A9.5:2013 pdf free download.Guide for Verification and Validation in Computation Weld Mechanics.
The development of integrated thermo-mechanical-metallurgical models is indeed challenging due to the complex interaction between physical processes during welding. Some of these physical processes include heat and mass transfer, phase transformations, electro-magnetic phenomenon, plastic strain, and reactions with environment during welding. Researchers have developed a framework for linking thermo-mechanical histories to microstructure development and mechanical heterogeneity in welds (see Annex B—Part C). These developments are again summarized in Figure 3.
According to Figure 3, by integrating individual sub-models for heat, mechanical, and material models, one can predict the overall performance of welded structures. The approach starts with a heat-transfer model thai simulates temperature distributions in three-dimensions [T =f(x, y, z. time)] as a function of process parameters and time. Thermal cycle data will be used by material models to predict the microstructure evolution and its impact on transient mechanical (o-t relations) properties. The transient changes in temperature and mechanical properties will he fed into a finite-element structural model to predict plastic strain distribution. This information allows for the prediction of final properties, residual stress, and distortion in a complex welded geometry. This interdisciplinary approach may appear simple; however, it requires collaboration between experts in metallurgy, finite element analyses, welding process, and computer science [62, 63]. To a limited extent, this vision has become a reality by pioneering work in many organizations and commercial software companies (see Annex B—Part D). There exist several conference proceedings that provide a detailed progression of integrated weld modeling and its capability for a wide range of joining processes (see Annex B—Part E). In addition, there are several useful classic textbooks related to modeling of welding processes (see Annex B—Part F).
5.3 Key Analysis Inputs. Key inputs are those that are either fundamental to the analysis, or that the analysis will be particularly sensitive to them. A CWM may contain thermal, metallurgical and structural analyses, and inputs and assumptions are addressed with respect to each.
5.3.1 Material Properties. Accuracy of the prediction by CWM relies on the accuracy of thermal, physical, mechanical, and metallurgical properties used by the models. Universally accepted, codified material properties for a wide range of materials do not exist as they do in other technology areas (e.g., the NIST Database of chemical properties, or the ASME Boiler and Pressure Vessel Code Section II. “Material Properties”). This unfortunate combination of sensitivity and uncertainty is largely counteracted by the use of a concept called the cutoff temperature; this concept is addressed in 5.6.1. For a certain subset of analyses, greatly simplified material properties have been found to be adequate when used in combination with test data. Examples are contained in the methods described in 5.7.AWS A9.5:2013 pdf free download.