Session: FSI-02-02 Acoustics

Paper Number: 122684

122684 - Predicting Acoustically Vibration Induced Resonance From Modal Analysis 

Detailed results from experiments and partial results for finite-element models from a joint industry project (JIP) to investigate acoustically induced vibration (AIV) have been presented in past conferences. This paper investigates the generated test results and finite element results to derive a method to determine a-priori the modes that may be excited. The method uses the dynamic stress concentration ratio, which is the ratio between the near field and far field stresses, to examine the ideal relationship for resonance between stress and velocity.  It was found that planar acoustic modes (<200Hz) also have the ability to excite higher order structural modes and can be AIV concern, this is termed low-frequency AIV. .Corresponding tail pipe and header resonances are further examined to determine the cases where the header may be non-resonant to tail pipe vibrations. While the stress at the welds is increased in relation to the ideal relationship for resonance, the vibration velocity is depressed in such non-resonant cases (>200Hz).  The paper also utilizes the entire pressure range of experiments (Inlet 400 to 50PSI, backpressure 0-100PSI) and entire range of finite element models i.e., reducing tee, sweepolet, stub-on, stub-on with full reinforcement pad and pipet in Std and schedule 10S thickness. The results will contribute to development of an agreed common methodology for finite element-based simulation using only modal responses in the early design phase when pipe support details are unknown to make macro decisions on connection types to be used.

Presenting Author: Arindam Ghosh KBR

Presenting Author Biography: Arindam has 26 years of industrial noise and vibration control experience and currently working for KBR. He is involved in a wide range of projects in the oil and gas, petrochemical, chemical and refining industries as well as space projects. Arindam has significantly improved KBR modeling tools and understanding of plant noise and vibration e.g., accounting for structural vibration in noise modeling, safe design of vent silencer systems, and finite element modeling of acoustically induced vibration. He did his B.Tech. in Mechanical Engineering from Indian Institute of Technology Kharagpur and M.S. in Aeroacoustics from the University of Houston.

Authors:

Raj Arjunan KBR
Yaying Niu KBR
Arindam Ghosh KBR
Denis Karzcub Energy Institute