COBEM99

S8 Engenharia Aeroespacial

Title:

SIZING AND TOPOLOGICAL OPTIMIZATION OF A SCIENTIFIC SATELLITE

Summary :

THE FRENCH-BRAZILIAN MICRO SATELLITE (FBMS) IS A SCIENTIFIC SATELLITE, WHICH WILL BE PIGGYBACK LAUNCHED BY THE LAUNCHER ARIANE 5. ITS MOST CRITICAL DESIGN CONSTRAINTS ARE: THE LOWER BOUND OF 40.0 HZ ON THE FIRST NATURAL FREQUENCY, IN ORDER TO AVOID COUPLING BETWEEN THE LAUNCHER S EXCITATION MODES AND THE NATURAL VIBRATION MODES OF THE SATELLITE; AND THE UPPER BOUND OF 10.5 KG ON THE STRUCTURAL MASS. THE STRUCTURE OF THE FBMS IS COMPOSED OF A CYLINDRICAL ALUMINUM ALLOY ADAPTER FOR CONNECTION WITH THE LAUNCHER, AND EIGHT SANDWICH PANELS (EACH COMPOSED OF THREE LAYERS) THAT DEFINE ITS TOPOLOGY. IN THIS PAPER, IT IS SHOWN THE IMPORTANCE OF STRUCTURAL OPTIMIZATION AND DESIGN SENSITIVITY ANALYSIS IN THE REDESIGN CYCLES OF SPACE STRUCTURES, BY PRESENTING ALL THE STEPS TAKEN AND THE DIFFICULTIES ENCOUNTERED WHEN TRYING TO MAXIMIZE THE FIRST NATURAL FREQUENCY FROM THE LOW VALUE OF 18.78 HZ OBTAINED WITH THE FIRST TRIAL DESIGN, WHILE MAINTAINING THE STRUCTURAL MASS BELLOW THE PREDEFINED UPPER BOUND. ALL THE MODAL AND SENSITIVITY ANALYSES AS WELL AS THE OPTIMIZATION STEPS WERE PERFORMED USING MSC/NASTRAN. THE DESIGN VARIABLE SPACE FOR THE STRUCTURAL OPTIMIZATION STEPS WAS COMPOSED OF THE THICKNESSES OF THE FACES AND CORE OF THE SANDWICH PANELS. KEY-WORDS: STRUCTURAL OPTIMIZATION, SENSITIVITY ANALYSIS, SPACE STRUCTURES

Author :

de Castro, Luciana Assis
Kataoka-Filho, Mário 0
Ravetti, Fernanda M. N.
Vidal, Creto Augusto

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