1、中文 3280 字 毕业设计（论文）外文资料翻译 学院： 机械工程学院 专业： 机械设计制造及其自动化 班级： 姓名： 学号： 外文出处： Tyler T J, Hill R, Lai E. Friction generated ultrasound from geotechnical materialsJ. Ultrasonics, 2004, 42(1): 169-172. 附 件： 1、外文原文； 2、外文资料翻译译文。 指导教师评语： 签字： 年 月 日 附件 1： Friction generated ultrasound from geotechnical materials TJ
2、 Tyler, R Hill, E Lai Abstract Drilling is a process involved with product manufacturing and for civil engineers, site preparation. The usual requirement is for efficient material removal. In this study, the friction pair interaction generated by a drilling process provides ultrasound information re
3、lated to parameters for the geotechnical material being drilled, where the drill bit has non-degrading ultrasonic characteristics and no essential requirement for material removal. This study has considered monitoring the ultrasonic signal generated by drilling process, with a view to characterising
4、 the parameters of the geotechnical material being drilled and provides a novel method to identify or characterise ground structures. Drilling of geotechnical material systems, typically involve the interaction of a rotating probe and a granular composite medium. The applied load and angular velocit
5、y are measured to determine their relevance to the ultrasonic signal. Samples of granular materials have been graded into controlled grain size ranges. Attention has been focused on determining the effects on the ultrasound signal of grain size, bulk density and the water content of the granular mat
6、erial. A comparison between the various granular samples of the different grain sizes, density, water content and the associated ultrasonic signal has been done. The effect of each variable, and existing theory for these effects is commented upon. The broad aim of this research is to evaluate ultras
7、onic monitoring of drilling and assess its potential for real-time geotechnical ground condition monitoring applications and offer it as an alternative to existing methods. _ 2004 Published by Elsevier B.V. 1. Introduction The ultrasound generated from a solidsolid friction pair has been the main fo
8、cus of research concerning friction-generated ultrasound, mainly associated with rotating and reciprocating machines. A frictional process developed during relative movement between contacting materials has an inherent level of wear that eventually would result in failure. Monitoring the ultrasonic
9、signal generated from machinery has become an alternative condition-monitoring tool, as the generated signal contains information related to the microcondition of the friction pair. It is possible to detect when components of a machine are becoming worn and a thus reduce the risk of catastrophic fai
10、lure leading to production down time. Holroyd and Randall 1 discussed the sensitivity of using acoustic emission (AE) for detecting changes in lubrication, overloading, wear and review a number of different techniques used to analysethe acoustic signature. Further methodologies for analysing the fri
11、ction generated acoustic signatures were discussed by Bukkapatnam et al. 2 and provide a novel analysis technique based on chaos theory, wavelets and neural networks. Much of the research concerning condition monitoring focuses on the changes in the signal due to wear, but some research have also fo
12、cused on the parameters associated with the generated acoustic signal.Work by Diei 3 monitored the acoustic emission generated by tool wear during face milling and proposed a power function relationship between the AERMS voltage and the rate of frictional energy dissipationgiven by AERMS ekgssAaV Tm
13、=2 e1T where k and m are constants that depend on the AE measuring system and the material properties of the friction pair, g is a function of surface roughness and elastic properties of the friction pair, ss is the shear strength of the interfacial material, Aa is the visible area of contact and V
14、is the sliding velocity. The parameters g and Aa essentially define the real area of contact andtherefore, the AERMS is a function of the real area of contact, the shear strength and the sliding velocity. Results obtained by Dieis work also indicated a linear relationship between the AERMS and the s
15、liding velocity. Jiaa and Dornfield 4 monitored the AE generated by a pin on disk experiment, highlighting that the AE is caused by impulsive shock due to asperity collisions and micro-vibrations excited by stickslip phenomena. The research shows that the AERMS increases with load while a linear rel
16、ationship exists between the relative surface velocity and the AERMS. Sarychev and Shchavelin 5 describe the frictional process and the generated acoustic emission associated with it. Two general rules were established relating the rate of counting the acoustic pulses (count rate) to the sliding spe
17、ed of the friction pair and the applied load. The general rule for the dependence of the count rate N_ on the sliding velocity is in the form: N_ A t BvX e2T where A and B are constants and X P1. A similar relationship also applies for the dependence of the load on the count rate, but the exponent X
18、 61. A further relationship was expressed relating the AE activity to the regime of friction in elastic contact: N_ a k N0:71h0:71A0:71 c r0:90R1:60 a V e3T where N is the normal load, h the generalised elastic modulus, Ac the counter area of contact, r the surface asperity tip radius, Ra is the surface roughness and k is a
