A reduced modal parameter based algorithm to estimate excitation forces from optimally placed accelerometers. Issue 3 (4th March 2017)

• Record Type: Journal Article
• Authors: Gupta, Deepak K.; Dhingra, Anoop K.
• Is Part Of: Inverse problems in science and engineering. Volume 25:Issue 3(2017)
• Page Start: 397
• Page End: 417
• Publication Date: 2017-03-04
• Subjects: Load recovery -- force transducer -- D-optimum design -- accelerometer placement -- model reduction; Engineering mathematics -- Periodicals; Inverse problems (Differential equations) -- Periodicals; 620.001515357
• DOI: 10.1080/17415977.2016.1169276
• Languages: English
• ISSNs: 1741-5977

Abstract

Abstract: This paper presents a time domain technique for estimating dynamic loads acting on a structure from acceleration time response measured experimentally at a finite number of optimally placed accelerometers on the structure. The technique utilizes model reduction to obtain precise load estimates. The structure essentially acts as its own load transducer. The approach is based on the standard equilibrium equations of motion in modal coordinates. The modal parameters of a system – natural frequencies, mode shapes and damping factors – can be estimated experimentally from measured data, analytically for simple problems, or using the finite element method. For measurement of the acceleration response, there can be a large number of locations on the structure where the accelerometers can be mounted, and the precision with which the applied loads are estimated from measured acceleration response may be strongly influenced by the locations selected for accelerometer placements. A solution approach, based on the construction of D-optimal designs, is presented to determine the number and optimum locations of accelerometers that will provide the most precise load estimates. An improvement in the algorithm, based on reduced modal matrix, is further proposed to reconstruct the input forces accurately. Numerical examples that help understand the main characteristics of the proposed approach are also presented. The numerical results illustrate the effectiveness of the proposed technique in accurately recovering the loads imposed on discrete as well as continuous systems.