Residual Stress and SpringbackPrediction

Presenter: Jyhwen Wang, TAMUPIs: Bruce Tai and Jyhwen Wang, TAMU

Yannis Korkolis, UNHJian 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

3. Residual Stress and Springback Prediction

Industrial Need and Relevance:

Residual stress and springback

can affect the dimensional

accuracy and structure performance of formed parts.

NSF I/UCRC Planning Meeting Slide 3

3. Residual Stress and Springback Prediction

http://www.autoform.com/

3. Residual Stress and Springback Prediction

Project Objectives:

To develop effective methods to characterize residual stress and predict springback to improve product quality and reduce costs.

NSF I/UCRC Planning Meeting Slide 4

Material

http://www.freundcontainer.com/

Deformation Process

Residual Stress &Springback

3. Residual Stress and Springback Prediction

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

NSF I/UCRC Planning Meeting Slide 5

Materials and Design 50 (2013) 253-266.Acta Mechanica Sinca 32, 1 , (2016) 125-134. Metal Forming, Hosford and Caddell (2014)

X-Ray Diffraction (XRD)

• Bragg’s Law：2𝑑ℎ𝑘𝑙 sin 𝜃ℎ𝑘𝑙 = 𝑛𝜆

where λ is the wavelength of the radiation, 𝑑ℎ𝑘𝑙 is the lattice plane spacing of a family of crystallographic planes (hkl)

responsible for the Bragg peak and 𝜃ℎ𝑘𝑙 is the angular position of this diffraction peak. The peak will be observed at

an angle of 2𝜃ℎ𝑘𝑙 from the incident beam.

• 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.

• XRD can provide the full stress tensor.

X-Ray Diffraction (XRD) Facilities at Argonne (ANL)

Advanced Photon Source, ANLAbout 40 miles away from Northwestern

Sector 11 setup

Diffraction Pattern of the ADSIF Processed AA2024-T3 Material

X-Ray Diffraction (XRD) Facilities at Argonne (ANL) and Northwestern

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

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

High-Energy XRD at APS (ANL) Microdiffraction at APS (ANL)

General Diffraction at APS (ANL) XRD at Northwestern University

3. Residual Stress and Springback Prediction

NSF I/UCRC Planning Meeting Slide 9

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

Forming

Simulation

Residual Stress

Measurement

Springback

Characterization

Tooling

Geometry

3. Residual Stress and Springback Prediction

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

3. Residual Stress and Springback Prediction

Budget and Timeline:

Estimated cost of the project is $330K.

NSF I/UCRC Planning Meeting Slide 11

Task / MilestoneYear 1 Year 2

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Material characterization

Design/Select Tooling

Forming Simulations/Prediction

Forming Experiments

Residual Stress Measurement

Springback Characterization

3. Residual Stress and Springback Prediction

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