Showing papers on "Design tool published in 1969"

Problems of skew in concrete bridge design

Abstract: THE PROBLEMS OF SKEW IN CONCRETE BRIDGE DESIGN ARE DISCUSSED AGAINST THE BACKGROUND OF AVAILABLE ANALYTICAL AND EXPERIMENTAL METHODS OF SOLUTION. THE INADEQUACY OF THE ANALYTICAL AND EXPERIMENTAL METHODS OF SOLUTION IS EMPHASIZED, BUT THE GREAT POTENTIALITIES AND VERSATILITY OF THE FINITE ELEMENT METHOD ARE RECOGNIZED. SPECIAL CONSIDERATION IS GIVEN TO THE ASSESSMENT OF STRESSES NEAR THE OBTUSE CORNERS AND IN STIFFENING BEAMS AS WELL AS THE INFLUENCE OF POISSON'S RATIO ON THE STRESS DISTRIBUTION. THE IMPORTANCE OF CONSIDERING STRUCTURAL MODEL ANALYSIS AND TESTING AS A DESIGN TOOL, AND THE AUGMENTING ASPECTS OF ANALYTICAL AND EXPERIMENTAL METHODS ARE DISCUSSED. DESIGN CONSIDERATIONS WHICH ARE PECULIAR TO SKEW BRIDGE DECKS ARE ELABORATED UPON. THE CALCULATION OF MOMENTS AND REACTIONS, EFFECTS GENERATED BY VARIATIONS IN THE NUMBER, SPACING, AND FLEXIBILITY OF SUPPORTS, THE PRESENCE OF A PRESTRESSING FORCE AND THE PROPORTIONING OF FLEXURAL REINFORCEMENT ARE CONSIDERED. ELASTIC, ULTIMATE STRENGTH AND LIMIT DESIGN PROCEDURES ARE BRIEFLY DISCUSSED AND THE NEED FOR FURTHER RESEARCH IS EMPHASIZED. THE POSSIBILITY OF DEVELOPING DESIGN AIDS IN FORMS OF TABLES AND GRAPHS IS BRIEFLY EXAMINED. IT IS PROPOSED THAT CLAUSES PERTAINING TO THE PROBLEM OF SKEW BE INCORPORATED INTO EXISTING BRIDGE SPECIFICATIONS. /CGRA/RRL/A/

Armor systems development/evaluation guideline

Abstract: : This guide was developed to establish a systematic approach to the design of aircrew armor systems. It provides an integrated investigation of the feasibility of adding armor to an aircraft based on the aircraft's systems, mission and performance requirements; and the assessment of the aircrew's 'protection need' based on the aircraft's mission, environment, required aircrew functions, and inherent ballistic protection provided the crew by the aircraft components. The data derived from these analyses are synthesized into an Armor Design/Evaluation Methodology which utilizes a complex computer-graphics technique as a design tool. To illustrate this computer technique, several sample armor configurations modeled on the UH-1C aircraft are developed and evaluated. The effectiveness of this method, however, depends upon the accuracy of the input data generated and upon the application of human factors design principles.