DEVELOPMENT OF ADVANCED FINITE ELEMENTS FOR STRUCTURAL ANALYSIS

MANY INDUSTRIAL FIRMS IN THE UNITED STATES RELY HEAVILY ON FINITE ELEMENT STRUCTURAL ANALYSIS. THIS IS PARTICULARLY TRUE OF THE AEROSPACE AND AUTOMOTIVE INDUSTRIES. THIS PROPOSAL OFFERS AN OPPORTUNITY TO IMPROVE THE RETURNS ON THIS INVESTMENT BY PROVIDING MORE ACCURATE RESULTS AND REDUCED COMPUTING TIMES. IT IS BASED ON AN APPROACH CALLED THE "INTEGRATED FORCE METHOD". LIKE THE STANDARD FORCE METHOD, THE IFM OFFERS INCREASED ACCURACY, ESPECIALLY IN STRESS CALCULATIONS, BUT DOES NOT REQUIRE SELECTION OF REDUNDANTS. THE PRESENT PROPOSAL USES A DERIVATIVE OF THE IFM, CALLED THE DUAL IFM. THE DUAL FORMULATION PRESERVES MOST OF THE BENEFITS OF THE IFM WITHIN THE CONTEXT OF A DISPLACEMENT-BASED FINITE ELEMENT COMPUTER PROGRAM. THIS MAKES IT POSSIBLE TO INTRODUCE NEW IFM ELEMENTS INTO A CODE LIKE NASTRAN WITH MINIMAL DISRUPTION, TAKING ADVANTAGE OF MOST OF THE EXISTING FACILITIES OF NASTRAN. SOME PRELIMINARY RESULTS ARE AVAILABLE FOR SIMPLE PLATE BENDING TEST PROBLEMS. THE DISCRETIZATION ERRORS SHOWN BY THE NEW ELEMENTS ARE CONSIDERABLY SMALLER THAN THOSE PRODUCED BY TWO ESTABLISHED CODES, ASKA AND MSC/NASTRAN, BY FACTORS OF FIVE OR MORE.