Verification and validation of ICME methods and models for aerospace applications

225

113

Additive manufacturing (AM), widely known as 3D printing, is a direct digital manufacturing process, where a component can be produced layer by layer from 3D digital data with no or minimal use of machining, molding, or casting. AM has developed rapidly in the last 10 years and has demonstrated significant potential in cost reduction of performance-critical components. This can be realized through improved design freedom, reduced material waste, and reduced post processing steps. Modeling AM processes not only provides important insight in competing physical phenomena that lead to final material properties and product quality but also provides the means to exploit the design space towards functional products and materials. The length-and timescales required to model AM processes and to predict the final workpiece characteristics are very challenging. Models must span length scales resolving powder particle diameters, the build chamber dimensions, and several hundreds or thousands of meters of heat source trajectories. Depending on the scan speed, the heat source interaction time with feedstock can be as short as a few microseconds, whereas the build time can span several hours or days depending on the size of the workpiece and the AM process used. Models also have to deal with multiple physical aspects such as heat transfer and phase changes as well as the evolution of the material properties and residual stresses throughout the build time. The modeling task is therefore a multi-scale, multi-physics endeavor calling for a complex interaction of multiple algorithms. This paper discusses models required to span the scope of AM processes with a particular focus towards predicting as-built material characteristics and residual stresses of the final build. Verification and validation examples are presented, the over-spanning goal is to provide an overview of currently available modeling tools and how they can contribute to maturing additive manufacturing.

Section: Modeling Readiness For Real-life Ammentioning

confidence: 99%

Metal additive-manufacturing process and residual stress modeling

Megahed

Mindt

N’Dri

et al. 2016

225

113

“…Tool assessments were performed to obtain maturity level (TML), as described by Cowles et al [17], for each of the ICME computer codes in the framework. For micro-models, the maturity was estimated at four to five.…”

Section: Verification and Validationmentioning

confidence: 99%

Towards rapid qualification of powder-bed laser additively manufactured parts

Peralta

Enright

Megahed

et al. 2016

Qualification of aerospace components is a long and costly process involving material properties, material specifications, manufacturing process, and design among others. Reducing qualification time and cost while maintaining safety offers a large economic advantage and enables faster response to the market demands. In 2012, DARPA established the Open Manufacturing program, a project to develop an integrated computational materials engineering (ICME) framework aimed at rapid qualification. Rapid qualification requires the integration of several technologies: materials, process, design, models, monitoring and control, non-destructive evaluation (NDE), testing, among others. A probabilistic design approach is adopted in the rapid qualification process to enable the integration of these technologies into a single risk-based function to optimize the design process. This approach directs the efforts to those areas that play the most important roles, potentially reducing specimen testing that will be required to develop material databases and design limits. New tests also will be required to validate and verify the ICME framework and develop a better understanding of the processing-microstructure-property relation and associated variability of the processing conditions. The probabilistic design approach is demonstrated for the rapid qualification of an actual aircraft engine component constructed via the powder-bed additive manufacturing process. This paper summarizes the probabilistic rapid qualification design approach and its application to this novel manufacturing process with the goal of reducing the overall qualification process time by 40 % and qualification process cost by 20 %.

“…The rationale and approach for developing these guidelines and practitioner aides were described in a journal article in 2012 [2]. The initial versions of the recommended best practice, practitioner aides such as V&V checklists, a Tool Maturity Level (TML) assessment approach, and a recommended approach to assess risk vs. consequences of ICME application were appended as additional files accessible through the IMMI journal reference.…”

Section: Background and Hypothesismentioning

confidence: 99%

Update to recommended best practice for verification and validation of ICME methods and models for aerospace applications

Cowles¹,

Backman

Dutton

2015

Background: Rigorous verification and validation practices are regarded essential for successful implementation of Integrated Computational Materials Engineering (ICME) for aerospace applications. Guidelines and a recommended best practice for ICME verification and validation were developed in 2011 under Air Force Research Laboratory sponsorship and were published in 2012. These included general guidelines for ICME verification and validation, a recommended best practice, practitioner aides in the form of checklists for planning and status assessment, a Tool Maturity Level assessment guide, and a recommended approach for risk vs. consequence assessment for specific ICME applications. ICME development programs and expert practitioners have since reviewed and used the guidelines and provided constructive feedback for improvements. Findings: This feedback was used to generate a comprehensive revision to the original guidelines and recommended best practice, as well as to the corresponding practitioner aides. The System-Level and Model-Level Checklists were simplified and improved, as was the Tool Maturity Level assessment guide. A template for a one-page summary chart was also generated to facilitate communication of status. Conclusions: Experience with several ICME-related programs and expert practitioners reinforced the conclusion that guidelines and a recommended best practice are important tools to ensure that rigorous, comprehensive verification and validation practices are employed during ICME development and implementation efforts.