Modal testing

About: Modal testing is a research topic. Over the lifetime, 4047 publications have been published within this topic receiving 64772 citations.

Effectiveness of particle and mass impact damping on tool vibration during hard turning process

Abstract: In the machine tools, tool vibration is an undesirable phenomenon which affects tool life, quality of machined surface and produces irritating noise. This tool vibration is due to the interaction between metal cutting process and forces acting on the machine tool. In this investigation, an attempt was made to reduce tool vibration during turning of hardened steel using particle and mass impact dampers. A mass impact damper used in this investigation consists of a concentrated mass made of copper mounted on the bottom of the tool holder and particle damper consists of copper particles of 3.5 mm diameter positioned along the axis of the tool holder. Particle size and its location were designed using computational analysis and impact hammer–based modal testing was performed for both dampers. When these dampers were mounted on the tool holder, particles will collide with each other and subdue the vibration produced in the tool holder. Cutting experiments were conducted to study the influence of mass and parti...

Development of an on-line parameter estimation system using the discrete modal filter

Abstract: Ongoing development of an automated system for monitoring the frequency and damping of time varying structural systems is discussed. A spatial filtering technique called the discrete modal filter is used to uncouple multiple response measurements into modal coordinate responses. Since the modal coordinate responses are the responses of single-degree-of-freedom systems, the frequency and damping may be accurately estimated with short data records. An on-line monitoring system is discussed which may be useful in a variety of applications. The focus in this paper is on the application to aircraft flight flutter testing.

Verification of equivalent mass–spring–damper models for crowd–structure vibration response prediction

Abstract: This paper describes the modal testing and in situ vibration monitoring of a high profile UK stadium during 2004 and 2005, including multiple concerts and sports events. The paper explains how current design guides pertaining to crowd dynamic loading of grandstands can be practically implemented using experimental modal data or finite element (FE) models. Three major pieces of guidance are considered: Canadian, ISO, and UK. Particular attention is given to new UK Recommendations as they are a major diversion from other methods and have yet to be robustly verified against real events on full-scale structures. This paper is therefore a unique verification exercise for all three guidelines because it makes use of rare combined in situ video and structural vibration response data pertinent to crowd dynamic loading of grandstands. Canadian guidance is found to predict the order of magnitude of responses well but lacks reliable precision, whilst the UK Recommendations are found to be very good at recreating res...