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Validation of post-buckling behaviour of unstable cross-section structures under compression loads. Authors : Silvia Ortiz Santamaria Angel Martinez Aja. ITP CAPACITIES. DESIGN ,MANUFACTURE and PRODUCT SUPPORT. GAS TURBINE. Rotating components. Static components. Casing.
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Validation of post-buckling behaviour of unstable cross-section structures under compression loads Authors : Silvia Ortiz Santamaria Angel Martinez Aja 2002 3RD Worldwide Aerospace Conference and Technology Showcase
ITP CAPACITIES DESIGN ,MANUFACTURE and PRODUCT SUPPORT GAS TURBINE Rotating components Static components Casing RADIAL STRUCTURES NOZZLE 2002 3RD Worldwide Aerospace Conference and Technology Showcase
WHY POST-BUCKLING? Aeronautical structures weight improvement More reliable structures Great competitiveness APPLICATIONS Engine radial structures Casings for aircraft engines 2002 3RD Worldwide Aerospace Conference and Technology Showcase
ADVANTAGES Traditional methodology of post-buckling analysis particular geometries and load types Post-buckling analysis using FEM general methodology for any geometry and load type Is FEM post-buckling analysis reliable? 2002 3RD Worldwide Aerospace Conference and Technology Showcase
P Crippling load Local buckling load Stable behaviour Local buckling P P d CRIPPLING ANALYSIS PROBLEM DEFINITION FOR FEM POST-BUCKLING VALIDATION Crippling = Post-buckling Residual strength analysis after local buckling 2002 3RD Worldwide Aerospace Conference and Technology Showcase
TWO CORNER FORMED CROSS-SECTIONS X785-C SECTION LS-160 SECTION MULTI CORNER FORMED CROSS-SECTION B2-SHAPE SECTION Tested specimens from NACA 3784 Material: AlClad2024-T3 CRIPPLING ANALYSIS PROBLEM EXAMPLES ANALYSED 2002 3RD Worldwide Aerospace Conference and Technology Showcase
CRIPPLING ANALYSIS FEM SIMULATION USING MSC.Nastran Analysis Steps 1.- FEM using QUAD4 elements 2.- Linear buckling analysis to obtain the column length representative of the behaviour of an infinite long column. 3.- FEM perturbation of initial geometry with MSC.Patran. 4.- Non-linear static analysis (elasto-plastic material behaviour + large displacement) toobtain the collapse load/stress. 2002 3RD Worldwide Aerospace Conference and Technology Showcase
X785-C section First buckling Mode 9526 psi 2002 3RD Worldwide Aerospace Conference and Technology Showcase
X785-C section Test Crippling Stress: 30489 psi [Ref. NACA 3784] FEM Crippling Stress: 29700 psi Error = 2,65% Displacements at crippling point Displacement-Load Curve 2002 3RD Worldwide Aerospace Conference and Technology Showcase
Y R 3/16 t = 0.04 1 Central Point R 1/8 X 5/8 LS-160 section First buckling Mode 33830 psi 2002 3RD Worldwide Aerospace Conference and Technology Showcase
LS-160 section Test Crippling Stress: 32400 psi [Ref. NACA 3784] FEM Crippling Stress: 33710 psi Error= 4.0 % Displacements at crippling point Displacement-Load Curve 2002 3RD Worldwide Aerospace Conference and Technology Showcase
MSC.Nastran results available crippling test data 2002 3RD Worldwide Aerospace Conference and Technology Showcase
0.082 t=0.032 1.198 R=3t 0.445 1.001 B2-Shape section First buckling Mode 13390 psi 2002 3RD Worldwide Aerospace Conference and Technology Showcase
B2-Shape section Test Crippling Stress 27100 psi [Ref. NACA 3784] FEM Crippling Stress 27893 psi Error= 2,9 % Displacements at crippling point Displacement-Load Curve 2002 3RD Worldwide Aerospace Conference and Technology Showcase
MSC.Nastran results available Crippling test data 2002 3RD Worldwide Aerospace Conference and Technology Showcase
CONCLUSION Post-buckling analysis using finite element method offers a general methodology for any geometry and load type Validated technology 2002 3RD Worldwide Aerospace Conference and Technology Showcase