NONLINEAR RESPONSE OF ACID STORAGE TANK COUPLED WITH PIPING ATTACHMENT UNDER SEISMIC LOAD FOR OPTIMAL SAFE DESIGN

Abstract

OPTIMUM SAFE DESIGN THROUGH NUMERICALLY INVESTIGATION AND SIMULATION OF FLUID STRUCTURE INTERACTION DUE TO SEISMIC LOADING ON ACID STORAGE TANK WITH PIPING ATTACHMENT IS PRESENTED. THE SEISMIC RESPONSE RELATIVELY DIFFERENT FROM CONVENTIONAL STRUCTURES DUE TO HYDRODYNAMIC FORCES ACTING ON THE TANK SHELL AND PIPE WALLS AND ALSO DUE TO MANY OTHER NONLINEAR FACTORS SUCH AS SLOSHING, FLUID-STRUCTURE INTERACTION, LARGE DEFECTION AND GEOMETRIC NONLINEARTIES. A NONLINEAR FLUID-STRUCTURE INTERACTION BASED ON THE FINITE ELEMENT METHOD IS PERFORMED ON A FULL-SCALE 3D MODEL. INVESTIGATIONS ARE SUPPLEMENTED BY A COMPUTATIONAL FLUID DYNAMIC ANALYSIS TO SIMULATE THE FLUID MOTION INSIDE THE TANK USING FULL-SCALE RESPONSE ACCELERATION TIME HISTORY OF KOCAELI EARTHQUAKE MAGNITUDE 7.4, RESPONSE OF THE MAXIMUM STRESS, DEFORMATION, AND DISPLACEMENT OF PIPING ATTACHMENT FOR RIGIDLY RESTRAINED FIXED AND FLEXIBLE TANKS AT DIFFERENT FLUID FILL LEVELS AND THICKNESS ARE EVALUATED. THE RESULTS ARE COMPARED AND ANALYZED WITH DESIGN CODES AND THE DIFFERENCE OBSERVED IN HYDROSTATIC PRESSURE IS LESS THAN 0.08%, AND THE DIFFERENCES OBSERVED IN MAXIMUM VALUES OF HYDRODYNAMIC PRESSURE ARE LESS THAN 4.3 %, 0.8% AND 1.5% AT THREE FLUID FILL LEVEL WHILE AVERAGE DIFFERENCE IN TRANSIENT TIME HISTORY TOTAL PRESSURE IS LESS THAN 0.4%. FINALLY, THE PROVISION GIVEN IN THE DESIGN CODES AND RESPONSE OF PARAMETERS OF PIPING COUPLED WITH AN ACID STORAGE TANK IS COMPUTED AND A SECOND ORDER POLYNOMIAL CORRELATION IS PROPOSED PER THE MINIMUM REQUIREMENT OF THESE CODES WITH ACCURACY OF ABOVE 0.9999 AND OVERALL AVERAGE DIFFERENCE LESS THAN 5% IN FIXED TANK AND IN FLEXIBLE TANK LESS THAN 2% FOR DESIGNING STORAGE TANK FOR OPTIMAL SAFE DESIGN BY ANALYSIS.