scholarly journals Modeling of Self-Vibratory Drilling Head-Spindle System for Predictions of Bearings Lifespan

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
F. Forestier ◽  
V. Gagnol ◽  
P. Ray ◽  
H. Paris

The machining of deep holes is limited due to inadequate chip evacuation, which induces tool breakage. To limit this drawback, retreat cycles and lubrication are used. An alternative response to the evacuation problem is based on high-speed vibratory drilling. A specific tool holder induces axial self-maintained vibration of the drill, which enables the chips to be split. The chips are thus of a small size and can be evacuated. To anticipate the potential risk of decreased spindle lifespan associated with these vibrations, a model of the behavior of the system (spindle—self-vibrating drilling head—tool) is elaborated. In order to assess the dynamic behavior of the system, this study develops a rotor-based finite element model, integrated with the modelling of component interfaces. The current results indicate that the simulations are consistent with the experimental measurements. The influence of spindle speed and feed rate on bearing lifespan is highlighted.

1990 ◽  
Vol 112 (3) ◽  
pp. 355-365 ◽  
Author(s):  
Yih-Hwang Lin ◽  
M. W. Trethewey ◽  
H. M. Reed ◽  
J. D. Shawley ◽  
S. J. Sager

This paper describes the modeling and dynamic analysis of a high speed precision circuit board drilling machine. The drilling machine has two banks of movable drill spindles supported between parallel granite beams on an air bearing suspension. Each drill spindle is programmed to move laterally between the beams under the position control of a servo-feedback system. The drill spindles must complete a nominal 3.048 mm (0.12 in.) lateral move and a vertical drilling sequence every 200 ms. while maintaining an absolute positioning accuracy within 0.01778 mm (0.0007 in.). In order to meet these demanding specifications the dynamic behavior of the complete drill spindle/air bearing/granite beam system must be well understood. A specialized finite element model (FEM) is used to examine the dynamic responses of the critical components of this machine. The FEM code is capable of analyzing a sprung two degrees of freedom system moving on an elastic beam in an arbitrary fashion. The discussion concentrates on the engineering modeling considerations and compromises which were necessary to analyze the drilling machine with this computer code. The modeling rationale and use of experimental data to form an effective computer model capable of analyzing the dynamic behavior of the drilling machine are emphasized. Typical results from the finite element model are presented to illustrate the obtainable level of accuracy, detail and the limitations for modeling a system of this nature.


1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.


2013 ◽  
Vol 589-590 ◽  
pp. 157-162
Author(s):  
Ya Hui Hu ◽  
Qing Yun Zhang ◽  
Xiao Yu Yue

The changes of drilling forces during bone drilling provide a useful index for evaluating the risk of potential damage to the bone. The aim of the work is that an elastic-plastic dynamic finite element model is used to simulate the process of a drill bit drilling through the bone. The finite element model was set up in the Abaqus6.11; the prediction model of the drilling force was gotten by using the regression orthogonal experiment and data processing software Matlab7.0. Diverse values of drilling speed, feed rate and drill diameter are important factors which will lead to changes in the drilling forces. By controlling the drilling parameters can obtain the optimal drilling force. The results show that the diameter has the greatest influence on the drilling force, the drilling speed the second, the feed rate the last.


2010 ◽  
Vol 143-144 ◽  
pp. 863-867
Author(s):  
Yong Tang ◽  
Qiang Wu ◽  
Xiao Fang Hu ◽  
Yu Zhong Li

The milling process of hard-to-cut material high manganese steel ZGMn13 was simulated and experimental studied based on Johnson-Cook material model and shear failure model.The high speed milling processing finite element model has established adopting arbitrary Lagrangian-Euler method (ALE) and the grid adaptive technology,The influence of milling parameters to milling force is analyzed in the high speed milling high manganese steel process. The simulated and experimental results being discussed are matched well. It certifies the finite element model is correct.


Author(s):  
Chiara Silvestri ◽  
Louis R. Peck ◽  
Kristen L. Billiar ◽  
Malcolm H. Ray

A finite element model of knee human ligaments was developed and validated to predict the injury potential of occupants in high speed frontal automotive collisions. Dynamic failure properties of ligaments were modeled to facilitate the development of more realistic dynamic representation of the human lower extremities when subjected to a high strain rate. Uniaxial impulsive impact loads were applied to porcine medial collateral ligament-bone complex with strain rates up to145 s−1. From test results, the failure load was found to depend on ligament geometric parameters and on the strain rate applied. The information obtained was then integrated into a finite element model of the knee ligaments with the potential to be used also for representation of ligaments in other regions of the human body. The model was then validated against knee ligament dynamic tolerance tests found in literature. Results obtained from finite element simulations during the validation process agreed with the outcomes reported by literature findings encouraging the use of this ligament model as a powerful and innovative tool to estimate ligament human response in high speed frontal automotive collisions.


Author(s):  
Shakti P. Jena ◽  
S. Naresh Kumar ◽  
Hemanth Cheedella

Abstract The present study is based on the transverse vibration analogy of a string subjected to a travelling mass. The string is considered to be fixed at their both ends. The responses of the string due to the dynamic behavior of the travelling mass are determined using a numerical approach i.e. Green’s function. A Finite Element Model (FEM) has been developed to authenticate the numerical approach. For the responses analysis of the string, numerical example has been illustrated to study the behavior of the string due to the travelling mass and to check the convergence of the two proposed analogies (Green’s function and FEM). The complete analysis has been performed at constant travelling speed and different masses. The two approaches converge well and the Green’s function methodology found to be suitable one.


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