6926475943

Key Word*: Forging machinery. No iw source Identification, Multipoint excitation technique

The application of mułtiple input model* to anaiyze rtruc-turally generated no i te from a forge Hammer i* discussed. Thi* articla i* intended to preient the rationaie for application and analytis of mułtiple input modeli for noiee *ource Identification. The deveiopment of the empirical model* i* reviewed and investigated to *how how the term* in the model can be interpreted to mathematically limulate the *alective wrapping approach to aource Identification. The interaction of the structural excitation forces and radiated structural noite i* examined for a four-piece forge Hammer and provide* an indication of the chara eter ist k: measurement* naeded to develop the mułtiple input model that i* repre-*entative of the hammer'* sound radiation. The traniducer requirementt for application to forge Hammer* ara examined through experiments performed on a laboratory test struc-ture and a forge hammer column. The resułts indicate that a single, well-placed traniducer may be sufficient to charac-terize the sound radiation from a monolithic element.

84-1577

Devełopment and Application of Mułtiple-Input Modela for Structural Noiee Source Identification of Forge Hammera. Part II - Application

M.W. Tretheweyand H.A. Evensen Penn$ylvania State Univ., University Park, PA 16802, J. Acoust. Soc. Amer.. 75 (4). pp 1099-1104 (Apr 1984) 6 figs, 3 tables, 3 refs

Key Word*: Forging machinery, Noise source Identification, Multipoint excłtation technique

Thi* article anaiyze* the application of the muttiple-input model i ng technique to the structural noise source Identification of a Chamberiburg no. 8 die forger. A co m per i son of three-, five-, and seven-lnput model* applied to the forge hammer under production conditions indicate* that as few a* five traniducer* would suffice to characterize the sound contributions of the fłve structural element*. Analysis of these model* indicate* that the ram i* the dominant source of sound energy, the column* are secondary source*, and th« yoke and anvil are minor source when detected through a microphone at the operator'* posłtion. The analysis also show* that the coupling between the hammer structural element* i* sufficient to render conventk>nel wrapping Identification method* unreliable for analyzing hammer noise.

84-1578

Machinę Tool Modificatioiu with Tuned Dam per*

P.J. Riehle and D. Brown

Anatrol Corp., Cincinnati, OH, S/V, Sound Vib., 18 (1), pp 34-39 (Jan 1984) 14 figs, 8 refs

Key Word*: Machinę tools, Chatter, Dynamie vibration absorption (aquipment), Viscoala*tic damping

Machinę tool vibration problem* associatad with chatter and how these problem* can be corrected with the application of tuned dam per* are discussed. The fundamenta!* of self-axcited and forced machinę tool chatter and techniquet for reducing chatter are briefly described. The proces* of designing tuned damper* for structural modifications i* reviewed with special emphasis placed on the selection of viscoetostic damping materiał*. A cate study involving a machinę tool chatter problem and rts solution with a tuned damper is described in detail.

84-1579

On-Line Identification and Control of Machining Chatter in Turamg through Dynamie Data System Methodology

Shing-Yuan Tsai

Ph.D. Thesis, Univ. of Wisconsin-Madison, 286 pp (1983)

DA8323406

Key Word*: Chatter, Machinę tools, Vibration control

The time-varying stabillty of the machining proces* nece*-titates a technique of on-line chatter identif ication and control. In a *ix-*tage study, *uch a technique was *ought. The thaoretical derivation and developed strategy prewnted in thi* study hava provided a solid batis for developing a chatter free fathe.

STRUCTURAL SYSTEMS

BRIDGES

84-1580

Experimental and Anałytical Erahiation of Cauaes of Cracfcing in Precaat Panel Highway Bridges

F.E. Fagundo and C.O. Hays. Jr.

Univ. of Florida. Gainesville, FL, ISA Trans., 23 (1). pp 1-9 (1984) 10 figs. 6 refs