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Florent COCHENNEC, Emmanuelle ROUHAUD, Bruno FLAN, Lionel ROUCOULES - Numerical simulation of peen forming induced deformations: modeling and experimental validation - 2011
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-1,2 -1 -0,8 -0,6 -0,4 -0,2 0 0 50 100 150 200 250 300 Distance (mm) Displacement (mm)
M easured - Peening D irection
M easured - Norm al to p eening direction Sim ulated - Peening direction
Sim ulated - N orm al to peening direction
Numerical simulation of peen forming
induced deformations: modeling and
experimental validation
CONTEXT
F. Cochennec
1*, E. Rouhaud
2, B. Flan
3, L. Roucoules
41
LBMS, EA CNRS 4325, Universite de Bretagne Occidentale, 29285 Brest, France.
2ICD-LASMIS, FRE CNRS 2848, Univ Tech Troyes, 10010 Troyes, France.
3
SISSON LEHMANN – Norican group, 08000 Charleville-Mezieres, France.
4LSIS, UMR CNRS 6168, ENSAM, 13617 Aix-en-Provence, France.
• Experimental and numerical study of the peen forming process: study of the deformation mechanisms involved in shot-peening.
• The scope of the work is to identify data that permit to simulate the peen forming process.
• The choice of plastic strains as process data is made. The plastic strains induced by the impacts are identified on simple cases and then
numerically introduced in a Finite Element program to predict the deformation of more complex parts.
EXPERIMENTAL CASES
Partially shot-peened aluminum 2024T3 alloy plates
NUMERICAL SIMULATION
CONCLUSION
FURTHER WORK
b)
Measurements show the influence of the shot-peening path on the global deformations. Negligible for relatively thick specimens.
Appreciable for relatively thin specimens.
Peen forming simulation gives good results for these first application cases.
Investigation of the deformation mechanisms of thin metallic parts.
To give a better understanding of the influence of the shot-peening path. Application to more complex geometries.
To fit the industrial needs (large aeronautical stiffened panels).
Peening Zone 200 mm 50 mm 300 mm Peening direction
Totally shot-peened aluminum 2024T3 alloy plates
Peening Path -1,2 -1,0 -0,8 -0,6 -0,4 -0,2 0,0 0 20 40 60 80 100 120 140 160 Distance (m m ) Displacem ent (mm )
M easured - N orm al to peening direction
M easured - Peening direction
-4,0 -3,5 -3,0 -2,5 -2,0 -1,5 -1,0 -0,5 0,0 0 20 40 60 80 100 120 140 Displacem ent (m m) Distance (mm)
Measured - Normal to peening direction Measured - Peening Direction
-4,0 -3,5 -3,0 -2,5 -2,0 -1,5 -1,0 -0,5 0,0 -200 -150 -100 -50 0 50 100 150 200 Distance (m m ) Displacem ent (m m)
M easured - Norm al to peening direction
M easured - Peening direction
-24 -19 -14 -9 -4 1 -100 -80 -60 -40 -20 0 20 40 60 80 100 Displacem ent (m m) Distance (m m )
M easured - Peening direction
M easured - N orm al to p eening direction
Measured displacements after shot-peening (3-axial measuring machine)
a) 5 mm thick specimen b) 2 mm thick specimen
a)
b)
Measured displacements after shot-peening (3-axial measuring machine)
a) 5 mm thick specimen b) 2 mm thick specimen
• No influence of the peening path on global deformations for relatively thick specimens.
• Huge influence of the peening path on global deformations for thin specimens (cylindrical form depending on peening direction).
Incremental Hole Drilling results
• Classical method using strain gages.
• Model based on eigenstrains theories. Elastic FE problem with initial strains. • Numerical model coupled to optimization program to identify plastic strains. • Plates supposed to be free of external constraints during drilling.
0 100 200 300 400 500 600 0,00 0,20 0,40 0,60 0,80 1,00 1,20 Hole depth (mm) Microstrain (10-6)
Normal to peening direction Peening direction
Simulated - Normal to peening direction Simulated - Peening direction
0 100 200 300 400 500 600 700 800 0 0,2 0,4 0,6 0,8 1 1,2 Hole Depth (mm) Microstrain (10-6)
Normal to peening direction Peening direction
Simulated - Normal to peening direction Simulated - Direction of peening
Numerical results – Partially shot-peened plates
a) 5 mm thick specimen b) 2 mm thick specimen
a)
b)
• Nearly equi-biaxial plastic strain field identified in 5 mm thick specimen.
• Plasticity oriented in the normal to peening direction in 2 mm thick specimen.
• Non realistic modeling of the boundary conditions of the 2 mm thick specimen: measured microstrains evolution do not correspond to the theoretical one.
Application to peen forming simulation
• Identified plastic strains as process data.
• Simulation of the shot-peening of the same materials, with the same process parameters.
-4,0 -3,5 -3,0 -2,5 -2,0 -1,5 -1,0 -0,5 0,0 -200 -150 -100 -50 0 50 100 150 200 Distance (mm) Displacement (mm)
M easured - N orm al to p eening direction M easured - Peening direction
Sim ulated - N orm al to p eening direction Sim ulated - Peening direction
Finite Element calculation
a)
Finite Element calculation
Numerical results – 5 mm thick specimens
a) totally shot-peened plate b) stiffened panel
Finite Element calculation -20 -15 -10 -5 0 -100 -80 -60 -40 -20 0 20 40 60 80 100 Displacement (mm) Distance (mm)
M easured - Peening direction
M easured - Norm al to peening direction Sim ulated - P eening direction
Sim ulated - N orm al to peening direction