TY - JOUR
T1 - Identification of noise sources of forge hammers during production
T2 - An application of residual spectrum techniques to transients
AU - Trethewey, M. W.
AU - Evensen, H. A.
N1 - Funding Information:
The authors gratefully acknowledge the financial support of the National Science Foundation, Division of Applied Research and the Forging Industry Educational and Research Foundation. The help and cooperation of the following companies were necessary in the performance of this research: A. Finkl & Sons, Company, construction and maintenance of a research hammer test site facility; Chambersburg Engineering Company for its aid in the test hammer conversion and consultation on hammer technology; Rockford Drop Forge Company, C&F Forge Company, Melling Drop Forge Company, Letts Drop Forge and Lindell Drop Forge Company, in field measurements and Erie Press Systems for providing engineering data on their impact forging equipment.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1981/8/8
Y1 - 1981/8/8
N2 - Three gravity-drop, four-piece forge hammers are analyzed to determine the principal structural sources of impulsive noise radiation during production forging. A three-input single-output model is used to describe the hammer system, based on "input" signals taken from one column, the anvil and the ram accelerations, and one "output" signal taken from the sound pressure at the operator's position. The frequency response functions between the elemental vibrations and the sound pressure signal are determined from these signals by residual spectrum techniques. For the three hammers studied, the analysis shows that the ram is a major source of acoustic energy radiated to the oeprator's position, while the columns and anvil radiate between 1 and 4 dB less energy. The three-input model is then used to estimate the effect of acoustic shrouds on the sound energy radiation. The results indicate that it may be necessary to treat all the structural elements before significant reductions can be achieved, due mainly to the high degree of interaction between the components. The residual spectrum derived from this model indicates that the three input model may not be totally adequate for all production hammers; it may be necessary to develop higher-input models, with use of data from more transducers located to sense a higher number of contributing vibration modes. However, in this study the three-input model accounted for 73-82% of the sound energy density at the operator's position.
AB - Three gravity-drop, four-piece forge hammers are analyzed to determine the principal structural sources of impulsive noise radiation during production forging. A three-input single-output model is used to describe the hammer system, based on "input" signals taken from one column, the anvil and the ram accelerations, and one "output" signal taken from the sound pressure at the operator's position. The frequency response functions between the elemental vibrations and the sound pressure signal are determined from these signals by residual spectrum techniques. For the three hammers studied, the analysis shows that the ram is a major source of acoustic energy radiated to the oeprator's position, while the columns and anvil radiate between 1 and 4 dB less energy. The three-input model is then used to estimate the effect of acoustic shrouds on the sound energy radiation. The results indicate that it may be necessary to treat all the structural elements before significant reductions can be achieved, due mainly to the high degree of interaction between the components. The residual spectrum derived from this model indicates that the three input model may not be totally adequate for all production hammers; it may be necessary to develop higher-input models, with use of data from more transducers located to sense a higher number of contributing vibration modes. However, in this study the three-input model accounted for 73-82% of the sound energy density at the operator's position.
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U2 - 10.1016/S0022-460X(81)80172-1
DO - 10.1016/S0022-460X(81)80172-1
M3 - Article
AN - SCOPUS:0019875515
SN - 0022-460X
VL - 77
SP - 357
EP - 374
JO - Journal of Sound and Vibration
JF - Journal of Sound and Vibration
IS - 3
ER -