Residual Stress and Springback Prediction Presenter: Jyhwen Wang, TAMU PIs: Bruce Tai and Jyhwen Wang, TAMU Yannis Korkolis, UNH Jian Cao, Northwestern
Executive Summary: Objective/Industrial Need: accurate springback prediction to achieve better part quality Approach: use x-ray diffraction and strain relaxation methods to characterize residual stress to improve model predictions of residual stress and springback Deliverable: Effective methods to characterize and predict residual stress and springback Budget and Timeline: $330k for 2 years; supports 3 RAs NSF I/UCRC Planning Meeting Slide 2
Industrial Need and Relevance: Residual stress and springback can affect the dimensional accuracy and structure performance of formed parts. http://www.autoform.com/ NSF I/UCRC Planning Meeting Slide 3
Project Objectives: To develop effective methods to characterize residual stress and predict springback to improve product quality and reduce costs. Material Deformation Process Residual Stress & Springback http://www.freundcontainer.com/ NSF I/UCRC Planning Meeting Slide 4
Approach/Methodologies: Proposed forming processes air bending, U-channel forming, deep drawing and microforming Residual stress measurement X-ray diffraction and strain relaxation Finite element simulation Materials and Design 50 (2013) 253-266. Acta Mechanica Sinca 32, 1, (2016) 125-134. Metal Forming, Hosford and Caddell (2014) NSF I/UCRC Planning Meeting Slide 5
X-Ray Diffraction (XRD) In our world, about 95% of the solid material can be described as crystalline. When X-ray beams encounters with a crystalline atoms inside the solid material, or more specifically, the metal or alloy material, the X-ray beam will be scattered or reflected. Bragg s Law: 2d hkl sin θ hkl = nλ where λ is the wavelength of the radiation, d hkl is the lattice plane spacing of a family of crystallographic planes (hkl) responsible for the Bragg peak and θ hkl is the angular position of this diffraction peak. The peak will be observed at an angle of 2θ hkl from the incident beam. XRD can provide the full stress tensor.
X-Ray Diffraction (XRD) Facilities at Argonne (ANL) Sector 11 setup Diffraction Pattern of the ADSIF Processed AA2024- T3 Material Advanced Photon Source, ANL About 40 miles away from Northwestern
X-Ray Diffraction (XRD) Facilities at Argonne (ANL) and Northwestern High-Energy XRD at APS (ANL) Microdiffraction at APS (ANL) Beamline Beam size (μm) Energy (KeV) 1-ID-B,C,E 1000 5 50-90 5-BM-D 15000 500 4.5-80 6-ID-D 1000 1000 70-130 11-ID-C 200 200 105.1 Beamline Beam size (μm) Energy (KeV) 13-ID-C,D 2 2 4.9-45 13-ID-E 1 1 2.4-28 16-ID-B 5 4 18-60 18-ID-D 150 50 3.5-35 24-ID-C 60 20 6.5-20 24-ID-E 120 20 12.68 34-ID-E 0.3 0.3 7-30 General Diffraction at APS (ANL) XRD at Northwestern University Beamline Beam size (μm) Energy (KeV) 11-ID-D 450 50 6-25 12-BM-B 1000 500 4.5-26 33-BM-C 900 500 5-35 33-ID-D,E 70 30 4-40 Instrument Beam size (μm) Energy (KeV) Scintag XDS2000 2000 500 8.04 Rigaku ATXG 2000 50 8.04 Rigaku Smartlab 2000 50 8.04
Approach/Methodologies: Characterize materials and evaluate constitutive models Conduct forming experiments and simulations to obtain residual stress and springback results one forming experiment aims to study the twist, the idea is to have a microforming setup such that in-situ residual stress measurement can be taken at ANL (Argonne National Lab) Compare model predictions to experimental results and identify effective modeling techniques Material Characterization Forming Processes Residual Stress Measurement Tooling Geometry Forming Simulation Springback Characterization NSF I/UCRC Planning Meeting Slide 9
Deliverables: Characterizing and comparing residual stress using X-ray diffraction and strain relaxation (and inverse) method Effective methods to characterize and predict residual stress Modeling techniques to accurately predict springback. NSF I/UCRC Planning Meeting Slide 10
Budget and Timeline: Estimated cost of the project is $330K. Task / Milestone Material characterization Year 1 Year 2 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Design/Select Tooling Forming Simulations/Prediction Forming Experiments Residual Stress Measurement Springback Characterization NSF I/UCRC Planning Meeting Slide 11
Discussion: Are the industrial need and relevance accurately captured? Are the objectives realistic and complete? Are the approaches technically sound and appropriate? Are there alternative implementation paths or better approaches? Are the deliverables impactful to industrial partners? Are the budget and timeline reasonable? Are there conflicts with intellectual property or trade secrets? List additional project specific questions are appropriate. NSF I/UCRC Planning Meeting Slide 12