msc.software worldwide aerospace conference and technology showcase toulouse, april 8-10, 2002

Worldwide Aerospace Conference and Technology Showcase 2002 1PAGE

AEROSPAZIODivisione Aeronautica

MSC.SOFTWARE

WORLDWIDE AEROSPACE CONFERENCE and TECHNOLOGY SHOWCASE

TOULOUSE, April 8-10, 2002

Numerical simulation of the Super Plastic Forming Process

of the

EFA – 2000 Under Carriage Door

F. Giordano– A. Natale – M. Calcagni

Alenia Aerospazio – Divisione Aeronautica

MSC. Software S.r.l. – Italy



NUMERICAL SIMULATION OF THE S.P.F. PROCESS OF THE NUMERICAL SIMULATION OF THE S.P.F. PROCESS OF THE EFA - 2000 UNDER CARRIAGE DOOREFA - 2000 UNDER CARRIAGE DOOR

OBJECTIVES AND GOALS

In the last years, more and more frequent utilization of the S.P.F.

to evaluate in advance the critical points

to adopt the right production strategies

to reduce the number of tests

to decrease the global costs

necessity in developing tools of numerical simulation




OBJECTIVES AND GOALS (CONT’D)

analysis and application of the new capabilities Marc

Tool chosen for the numerical simulation: MSC.Marc

comparison between numerical and experimental readings of the door thickness

numerical simulation of the S.P.F. process for the U/C Door

Steps followed:

Marc code applied to a concrete problem of the Alenia Aerospazio - Divisione Aeronautica:

S.P.F. of the Under Carriage Door of the EF2000

auto-adaptive remeshing

study of the simulation of the friction between die and forming plate

optimization of the loading curve




SUPERPLASTICITY

S.P.F. : process able to produce very complex structures, based on the superplasticity of various kind of material

Condition to be verified to have superplastic state:

grains’ little dimensions (110 m)forming temperature higher than 50% fusion temperaturelow deformation velocitystrain rate sensitivity factor at least equal to 0.3

In this state, possibility of undergoing very high deformation without necking

Superplasticity : particular state achieved by metals, alloys, ceramic materials in specific temperature and pressure conditions




S.P.F. SIMULATION FOR EF200 U/C DOOR

heated ( T= 485± 10°C) dies and presses are used;

initial plate thickness: 2.5 mm;

target strain rate=4*10-4 sec-1

transfer of the die geometric model from CATIA by Direct Access CATIA

realization of the F.E.M. model of the plate to be formed

reproduction of the F.E.M. model of the die

application of the real loading curve and of the real constraints

In the real process:

In the numerical simulation :



U/C DOOR EF2000


TEST

U/C DOOR



F.E. MODELS OF THE PLATE AND OF THE DIE


DIE

GRIDS: 77576SURFACES : 19394

PLATE

NODES : 14641ELEMENTS : 14400



MATERIAL CHARACTERIZING

Utilization of a law (Power law)n

mY BA

.

0 )( with : A=0n

Y B.

Bibliographic research to find the values of B ed n

Material isotropic and with a rigid-plastic law


by curve at 505 °C :

B=509.69 N*sec/mm2 n=0.65




LOADING AND CONSTRAINTS OF THE U/C DOOR MODEL

Numerical loading: the real differential pressure has been applied to the plate

Constraints: edges of the plate clamped

Real loading: hot pressurized air insufflated on the upper and on the lower part of the plate




RESULTS OF MSC.Marc ANALYSIS

HISTORY OF THE THICKNESS DISTRIBUTION





HISTORY OF THE THICKNESS DISTRIBUTION (CONT’D)



LOCATION OF THE EXPERIMENTAL AND NUMERICAL READINGS





EXPERIMENTAL-NUMERICAL READINGS CORRELATION

Location Exp. Readings Num. Readings % Gap3 1.82 1.95 7.144 1.84 1.81 1.635 1.61 1.59 1.246 1.45 1.46 0.697 1.53 1.43 6.538 1.6 1.57 1.879 1.86 1.85 0.5410 1.66 1.66 011 1.6 1.6 012 1.95 1.61 17.4313 2 1.97 1.514 1.95 1.99 2.0515 2 2.03 1.516 1.83 1.84 0.5517 1.8 1.84 2.2218 2 1.98 119 1.95 1.92 1.5420 1.8 1.7 5.521 2.02 1.94 3.9622 1.96 1.9 3.0623 2.04 1.97 3.4324 1.88 1.85 1.5925 1.77 1.97 11.2926 2.1 2.09 0.4927 1.85 1.76 4.86

Location Exp. Readings Num. Readings % Gap28 1,81 1,87 3,3129 2,14 2,17 1,430 2,12 2,13 0,4731 2,1 2,09 0,4732 1,96 1,78 9,1834 1,78 1,73 2,835 1,91 1,87 2,0936 1,7 1,63 4,1237 2 2,03 1,538 1,67 1,77 5,9839 1,8 1,74 3,3340 1,81 1,64 9,3942 1,9 1,84 3,1643 1,93 1,97 2,0744 2,05 1,91 6,8345 2,11 1,97 6,6350 2,02 1,96 2,9754 2,07 2 3,3855 2,11 1,89 10,4256 1,91 1,94 1,5757 2 2,02 158 2,02 2 159 2,05 1,77 13,6560 2,11 1,9 9,9561 2,09 2,06 1,43

PART A




EXPERIMENTAL-NUMERICAL READINGS CORRELATION

PART B

Location Exp. Readings Num. Readings % Gap1 2,14 1,99 7,002 1,94 1,98 2,063 1,94 2 3,094 1,97 1,96 0,515 1,97 2,02 2,536 1,98 2,07 4,547 1,8 2,11 17,28 1,9 2,04 7,39 2,06 2,14 3,8810 21 1,99 5,2311 1,9 1,89 0,5212 2,06 1,91 7,2814 2,08 2,01 3,3616 2,15 2,08 3,2518 2,1 2 4,7620 2,14 2,05 4,222 2,08 2,03 2,423 2,02 2,01 0,4924 2,23 2,13 4,4825 2,13 2,08 2,3426 1,97 1,96 0,5127 2,1 2,05 2,3828 2,13 2,13 029 1,95 2,07 6,1530 2,2 2,14 2,7231 2,02 2,06 1,98

Location Exp. Readings Num. Readings % Gap32 2,04 2,04 033 1,93 1,91 1,0334 2,13 2,22 4,2235 2,16 2,22 2,7736 2,03 1,92 5,4237 2,07 2,04 1,4538 2,05 2,12 3,4139 2,01 2,04 1,4940 2,29 2,35 2,6246 2,05 1,87 8,7847 2 2,05 2,548 1,95 1,96 0,5149 2,03 2,05 0,9850 2,12 2,12 051 2,12 1,85 12,7352 2,06 1,81 12,1357 2,09 2,02 3,3558 2,09 1,99 4,78A 2,37 2,3 2,95B 1,8 1,77 1,66D 1,81 1,68 7,18F 1,75 1,75 0G 2,37 2,36 0,42M 1,68 1,65 1,78N 1,69 1,66 1,77



STUDY OF DIE - PLATE FRICTION


Non perfect agreement in few points of readings study of new MSC.Marc capabilities

Attention on a quick tool: the “test” of the door

Realization of a new detailed F.E.M. for the die and for the initial plate related to the test



STUDY OF DIE -PLATE FRICTION (CONT’D)

Ffr=Fn2/ *arctan (Vr/RVCNST)*t

= 0

= 0.1

= 0.25

= 0.5


More reliable model of the friction (Coulomb friction):

Ffr=Fn

Model of the friction available from Marc :

Choice of RVCNST so that the Coulomb friction has been used

Friction coefficient unknown parametric study by utilizing various friction coefficients



TEST OF THE DOOR

FRICTION PARAMETRIC STUDY- = 0Thickness distribution




TEST OF THE DOOR

FRICTION PARAMETRIC STUDY- = 0.1Thickness distribution





TEST OF THE DOOR





TEST OF THE DOOR

FRICTION PARAMETRIC STUDY

Numerical-Experimental thickness correlation

Point Exp. Readings Num. Readings Num. Readings Num. Readings Num. Readings(=0) (=.1) (=.25) (=.5)

A 2.37 2.33 2.36 2.37 2.38B 1.8 1.75 1.72 1.67 1.66C 1.89 1.82 1.82 1.85 1.87D 1.81 1.55 1.66 1.7 1.75E 1.92 1.98 1.99 2 2.03F 1.75 1.73 1.73 1.71 1.7G 2.37 2.28 2.28 2.28 2.3H 1.85 2.05 2.01 1.99 1.98I 1.78 1.6 1.66 1.7 1.75L 1.87 1.86 1.87 1.89 1.9M 1.68 1.62 1.58 1.54 1.52N 1.69 1.62 1.58 1.54 1.51O 2.63 2.49 2.49 2.49 2.5P 2.26 2.48 2.49 2.49 2.49Q 2.5 2.49 2.49 2.49 2.5



STUDY OF OPTIMIZED LOADING CURVE


Operative application to improve the S.P.F. process: study of an optimized loading curve

By utilizing the new Marc capability, the loading curve is the main result

Necessity of indicating the direction, the versus of the loading and the maximum value of the pressure to be applied (p = 1N/mm2)

Choice of the “ending” termination



U/C DOOR EF2000

STUDY OF THE OPTIMIZED LOADING CURVE

Thickness distribution





Strain rates and V.M. stresses distribution

U/C DOOR EF2000





Thickness distribution

U/C DOOR EF2000





Strain rate distribution

U/C DOOR EF2000





U/C DOOR EF2000

STUDY OF THE OPTIMIZED LOADING CURVE WITH AUTO-ADAPTIVE REMESHING

Study of the new MSC.Marc capability to have a finer mesh in the critical zones

First level of remeshing




Thickness and strain rate distribution

U/C DOOR EF2000




SUMMARY OF THE TIME CALCULATION


Processor used: IBM RS/6000 449 Model 170 W/S - 1Gb of Ram 18 Gb of Internal Disk Drive



CONCLUSIONS


A study on the possibility of numerically simulating the S.P.F. has been performed

Numerical-experimental comparison demonstrates the opportunity of the Code MSC.Marc utilization like a good tool of numerical simulation

A study of simulation of die-plate friction has been performed

The capability of producing an optimized loading curve has been studied and applied

The capability of realizing an auto-adaptive remeshing has been explored

Advantages of a numerical simulation:

a more detailed knowledge of all the parameters of the process

possibility of knowing the optimized loading curve

numerical evaluation of the influence of the parameters on the process

reduction of the experimental tests

possibility of knowing the optimized thickness distribution of the initial plate

msc.software worldwide aerospace conference and technology showcase toulouse, april 8-10, 2002

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