Integrated Computational Materials Engineering: The Customer’s Point of View: ICME for Residual Stress
Program Organizers: Rollie Dutton, Air Force Research Laboratory; David Furrer, Pratt & Whitney
Monday 2:00 PM
October 8, 2012
Room: Room 326
Location: David L. Lawrence Convention Ctr
Session Chair: Pamela Kobryn, AFRL
2:00 PM
Modeling of Residual Stresses and Machining Distortions of Aerospace Components: Shesh Srivatsa1; 1GE Aviation
Aircraft engine and airframe structural components that are machined from forgings represent a significant cost of both military and commercial aircraft. The buy-to-fly weight ratio, which is the ratio of the forged material weight to the finished part weight, is typically between 4 and 10 for such components. Machining distortions are a problem with most forged components which are quenched rapidly in order to generate the required mechanical properties. Typically additional machining operations and setups are added in a time-consuming and costly trial-and-error approach to minimize the effects of part distortion. Manufacturing residual stresses can adversely impact the behavior of the components during service. There is a need to understand and control the effects of heat treating and machining on residual stresses and distortions. This presentation will describe the development and validation of residual stress and distortion models for forgings used in aircraft engines.
2:40 PM
Validation of Residual Stress Fields Determined from Material Process Models: Michael Hill1; Adrian DeWald2; 1University of California, Davis; 2Hill Engineering, LLC
Physical process models for structural materials support the emerging discipline of integrated computational materials engineering (ICME), and a key output from such models is an estimate of the residual stress field in a work piece following production processes (e.g., forging, rolling, machining, welding) or post-production processes (e.g., rework, repair). Validation of process models requires a comparison of outputs to truth data that are typically derived from measurement. While this can be straightforward for certain outputs (e.g., distributions of grain size, hardness, tensile strength), validation of residual stress fields is more complicated. Several examples serve to illustrate these complicating factors and offer insights on measurement approaches for validation of ICME material process models.
3:00 PM
The Emerging Role of ICME in Airframe Affordability: Dale Ball1; Craig Bridges1; 1Lockheed Martin Aeronautics Co.
With production run sizes decreasing and unit costs increasing, airframe manufacturers are aggressively pursuing the development of advanced materials, structures and manufacturing processes that will reduce cost without compromising structural integrity. In recent years the use of computational simulation for material discovery, design and development and for structural optimization has become increasingly widespread. This emerging discipline of Integrated Computational Materials Engineering is enabling design trade studies with improved fidelity and has shown the potential to reduce the amount of physical testing required for structures certification. Recently, studies have been performed in which computed residual stresses in large aluminum forgings were included in an advanced optimization of several bulkheads. These results were then used to inform a cost model that addressed sustainment, as well as manufacturing and performance costs. In this paper, using the forging studies cited above, we will describe the increasingly important link between ICME and viable affordability assessments.
3:40 PM Break
4:00 PM
The Role of ICME in the Airframe Digital Twin Concept: Pamela Kobryn1; Eric Tuegel1; Ravi Penmetsa1; 1AFRL
Reducing maintenance costs while ensuring the continued airworthiness and availability of aircraft in this era of constrained budgets requires revolutionary changes in the way aircraft are managed while in service. One revolutionary concept for changing the way aircraft are managed is the Airframe Digital Twin (ADT) concept. An ADT is a cradle-to-grave model of an aircraft structure's ability to meet mission requirements. The ADT, as an ultra-realistic computer model of the as-built and maintained airframe, is explicitly tied to the materials and manufacturing specifications, controls, and processes used to build and maintain the aircraft. It is a single consistent model of an individual airframe that includes all variation and uncertainty in that aircraft. ICME and the associated Digital Thread have been identified as key components of the ADT. This presentation will introduce the ADT concept and the technology challenges / technology requirements associated with ICME and the Digital Thread.
4:20 PM
Application of ICME to Weld Process Innovations and Residual Stress Management: Zhili Feng1; Wei Zhang1; Paul Crooker2; Eric Willis2; Ken Wolfe2; Stan David1; 1Oak Ridge National Laboratory; 2EPRI
The applications of ICME to advance welding technologies will be discussed. First, an integrated weld process-property-performance modeling framework will be described, as well as the experimental work for model development and validation including in-situ neutron/synchrotron experiments. Several examples of modeling applications are presented, for proactive weld residual stresses for nuclear power plant life-cycle management, design and engineering of innovative welding processes to repair irradiated materials, and to improve the weld fatigue life for automotive applications. Perspectives to integrate welding modeling into the overall manufacturing process and structure performance optimizations will be provided.
5:00 PM
Incorporation of Residual Stresses into Design of Ni-Base Superalloy Structures: A Foundational Engineering Problem in Integrated Computational Materials Engineering (ICME): Michael Caton1; 1US Air Force Research Laboratory
The Materials and Manufacturing Directorate of the Air Force Research Laboratory is investing in a Foundational Engineering Problem (FEP) aimed at incorporating residual stress into the design of Ni-base superalloy structures. FEPs, as conceived in the 2008 National Materials Advisory Board report entitled Integrated Computational Materials Engineering: A Transformational Discipline for Improved Competitiveness and National Security, consist of an advanced engineering component, a materials system, and a manufacturing process that must be rapidly optimized within a more complex engineering system. FEPs are intended to accelerate the development and application of ICME within the industrial base. The presentation will outline the process of developing this FEP topic through a collaborative exchange between the Air Force and a consortium of aerospace industrial members within the Metals Affordability Initiative. The criteria, upon which the proposal selection was based, will be discussed and a high-level description of this recently-initiated, 5-year program will be provided.