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Vibration Characterization and Numerical Modeling of a Pneumatic Impact Hammer

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dc.contributor.authorKadam, Rahul Sadashiven
dc.contributor.committeechairJohnson, Martin E.en
dc.contributor.committeememberInman, Daniel J.en
dc.contributor.committeememberBurdisso, Ricardo A.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T20:42:47Zen
dc.date.adate2006-10-16en
dc.date.available2014-03-14T20:42:47Zen
dc.date.issued2006-07-20en
dc.date.rdate2006-10-16en
dc.date.sdate2006-08-05en
dc.description.abstractHand transmitted vibration (HTV) is one of the most common hazards faced by workers in the construction industry. A major source of HTV is hand held percussion tools, such as pneumatically driven chipping hammers and rock drills. This thesis presents a new approach to measuring the vibration from these tools using an experimental hand arm model to which the tools are attached. The experimental hand-arm model has been designed to have similar dynamic characteristics to that of a human hand-arm system. This approach addresses the issue of repeatability as HTV measurements suffer from variability between cases. The measured acceleration of the hand-arm system is in range or close to range of the measured accelerations of the test subjects with superior repeatability. Further, the thesis presents a nonlinear numerical model of a pneumatic impact hammer. Fundamentally, the numerical model was made up of two different sub-models, 1) a fluid flow model and 2) a structural dynamic model. The fluid flow model was based on the equations for mass flow rate of air though a bleed orifice assuming an isentropic process. The second sub-model deals with modeling the structural components of the impact hammer consisting of the major hammer like the center body, handle, piston and chisel as well as the human hand and the ground. Time domain simulations of the hammer were carried out by using a state space formulation to get displacements, velocities and accelerations of the each component as well as the exhaust jet velocities. Experiments were carried out to measure the handle response and exhaust jet velocities as well as pressure profiles. The results obtained from the numerical model were then validated using these experimental results. Finally, a parametric study using the numerical model was carried out to explore different vibration control techniques.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-08052006-111525en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08052006-111525/en
dc.identifier.urihttp://hdl.handle.net/10919/34359en
dc.publisherVirginia Techen
dc.relation.haspartthesis_rkadam_2006.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectHand Transmitted Vibrationsen
dc.subjectState-space Modelingen
dc.subjectVibration and Acoustic Characterizationen
dc.subjectNumerical Modelingen
dc.subjectPneumatic Impact Hammeren
dc.titleVibration Characterization and Numerical Modeling of a Pneumatic Impact Hammeren
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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