Session: DA-09-02 Piping and Equipment Dynamics and Dynamic Response Analysis-2

Paper Number: 122624

122624 - An Application of Random Response Analysis for Analyzing Vibration Fatigue Failures Due to Liquid Impingement Loads 

Vibration fatigue failures of components or structures subjected to liquid impingement loads are common in oil and gas, and petrochemical industries.  The impulse force due to liquid impingement is random in nature as the magnitude of the force depends on factors such as the way in which liquid breaks-up as it falls, the variation in the droplet sizes, and the frequency of the droplets falling.  Often the designers estimate the impingement load as an equivalent static force based on the principles of rate of change of momentum.  While such static equivalent load is a good estimate for the time-averaged force, the use of such force alone in the design analyses is unconservative.  A better way to design the components for liquid impingement loads is to treat the impingement loads as random loading and analyze the components using random response analysis as discussed in this paper.  In the random response analysis, the liquid impingement load is defined in a statistical sense; power spectral density (PSD) as a function of frequency.  The stresses from the random response analysis are a measure of root-mean-square (RMS) stress.  Such RMS stresses can be compared to an RMS stress limit that can be obtained by integrating fatigue damage defined using a design fatigue (S-N) curve.  This paper discusses an application of the random response analysis for identifying the root cause of a pressure vessel’s internal deflector support cracking and the design changes to the deflector for protection against such vibration fatigue failures in the future.

Presenting Author: Seetha Ramudu Kummari The Equity Engineering Group, Inc.

Presenting Author Biography: Dr. Kummari is an engineer within the Advanced Analysis Group at E2G | The Equity Engineering Group, Inc. and provides engineering consulting services to the oil & gas, chemical, and nuclear industries on a wide variety of consulting projects. His areas of specialization include Fitness-For-Service using API 579, high temperature assessments, fatigue and fracture mechanics, and advanced stress and heat transfer analysis using Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD).

Dr. Kummari earned his Ph.D. in Mechanical Engineering from Case Western Reserve University, Cleveland, Ohio. As a part of his Ph.D. dissertation, he developed experimental and computational methods to assess fracture risks of bones in elderly people. He earned both his Bachelor’s and Master’s degree from a reputed educational institute in India, Indian Institute of Technology (IIT) Kharagpur.

Authors:

Seetha Ramudu Kummari The Equity Engineering Group, Inc.
Michael Bifano The Equity Engineering Group, Inc.
Derek Rinas The Equity Engineering Group, Inc.
Hassan Ishtiaque K+S Potash Canada