With the increment of working temperature in magneto-rheological (MR) absorber, the performance of the absorber will be significantly degraded. In order to improve the performance (MR) absorber considering the negative effect on output damping force, the six σ robust optimal method is proposed. The maximum damping force, the dynamic range, the power dissipation, and the fail-safe ability are analyzed in the optimal process. The fluctuations of several key geometrical parameters due to manufacturing tolerances or other uncontrollable factors are also considered to achieve the optimal objective. To increase computing efficiency of the optimal design procedure, the magnetic field model based on the response surface method is utilized to predict the distribution of the magnetic field intensity. The adaptive simulated annealing algorithm is used to solve the non-linear optimal problem. The numerical results show that the perturbation of output force can be reduced while the temperature is fluctuating, which means that the optimization process can alleviate the damping force’s sensitivity to the temperature fluctuation and increase the robust of the absorber. Subsequently, the performances of the semi-active suspension with the optimized absorber under different loads and temperatures are analyzed and the effectiveness of the optimization algorithm is confirmed.

Robust design of magneto-rheological (MR) shock absorber considering temperature effects

Deep hole boring using slender bars that have tuned mass dampers integrated within them make the boring process chatter vibration resistant. Dampers are usually designed using classical analytical solutions that presume the (un)damped boring bar which can be approximated by a single degree of freedom system, and the damper is placed at the free end. Since the free end is also the cutting end, analytical models may result in infeasible design solutions. To place optimally tuned dampers within boring bars, but away from the free end, this paper presents a receptance coupling approach in which the substructural receptances of the boring bar modelled as a cantilevered Euler–Bernoulli beam are combined with the substructural receptances of a damper modelled as a rigid mass integrated anywhere within the bar. The assembled and damped system response thus obtained is used to predict the chatter-free machining stability limit. Maximization of this limit is treated as the objective function to find the optimal mass, stiffness and damping of the absorber. Proposed solutions are first verified against other classical solutions for assumed placement of the absorber at the free end. Verified models then guide prototyping of a boring bar integrated with a damper placed away from its free end. Experiments demonstrate a ~100-fold improvement in chatter vibration free machining capability. The generalized methods presented herein can be easily extended to design and develop other damped and chatter-resistant tooling systems.

Design of Chatter-Resistant Damped Boring Bars Using a Receptance Coupling Approach

In boring process, tool vibration is an important parameter which results in progressive tool wear, poor surface finish and cutting tool damage. This tool vibration was reduced by passive, semi-active and active techniques which are used by various researchers in the past. In this paper, various techniques employed to prevent tool vibration in boring operation are reviewed, analyzed and presented. It was inferred that the control of tool vibration was effective by utilizing appropriate damping mechanism in the boring process. Also, from the overall review of the literature, it was observed that as the tool wear started to progress, the tool vibration gets increased which leads to failure of the tool. In this review paper, scope of developing a damper where tool vibration can be suppressed by varying the damping ability based on requirement was established.

Suppression of Tool Vibration in Boring Process: A Review

Tool vibration is a dynamic instability of cutting process, which is a result of interaction between metal-cutting process and dynamics of machined tool. In metal-cutting process, the presence of t...

Vibration control techniques during turning process: a review

A new cutting tool is always well-defined and sharp at the onset of the metal cutting process and gradually losses these properties as the machining process advances. Similarly, at the beginning of the machining process, amplitude of tool vibrations is considerably low and it increases gradually and peaks at the end of the service period of the cutting tool while machining. It is significant to provide a corresponding real-time varying damping to control this chatter, which directly influences accuracy and quality of productivity. This paper aims to review the literature related to the application of smart fluid to control vibration in metal cutting and also focused on the challenges involved in the implementation of active control system during machining process.,Smart dampers, which are used as semi-active and active dampers in metal cutting, were reviewed and the research studies carried out in the field of the magnetorheological (MR) damper were concentrated. In smart materials, MR fluids possess some disadvantages because of their sedimentation of iron particles, leakage and slow response time. To overcome these drawbacks, new MR materials such as MR foam, MR elastomers, MR gels and MR plastomers have been recommended and suggested. This review intents to throw light into available literature which exclusively deals with controlling chatter in metal cutting with the help of MR damping methods.,Using an MR damper popularly known for its semi-active damping characteristics is very adaptable and flexible in controlling chatter by providing damping to real-time amplitudes of tool vibration. In the past, many researchers have attempted to implement MR damper in metal cutting to control vibration and were successful. Various methods with the help of MR fluid are illustrated.,A new cutting tool is always well-defined and sharp at the onset of metal cutting process and gradually losses these properties as the machining process advances. Similarly, at the beginning of the machining process, amplitude of tool vibrations is considerably low and it increases gradually and peaks at the end of service period of cutting tool while machining. Application of MR damper along with the working methodology in metal cutting is presented, challenges met are analyzed and a scope for development is reviewed.,This study provides corresponding real-time varying damping to control tool vibration which directly influences accuracy and quality of productivity. Using an MR damper popularly known for its semi-active damping characteristics is very adaptable and flexible in controlling chatter by providing damping to real-time amplitudes of tool vibration.,This study attempts to implement smart damper in metal cutting to control vibrations.,It is significant to provide corresponding real-time varying damping to control tool vibration which directly influences accuracy and quality of productivity.

Application of smart fluid to control vibration in metal cutting: a review

In the manufacturing industry, most of the components are made by machining operations. The performance of the product to a large extent is dependent on the accuracy and consistency of the machinin...

Experimental Investigation on Boring Tool Vibration Control Using MR Fluid Damper

The current investigation presents the wear-worn surface analysis of a silicon carbide-reinforced brass-based composite synthesized by stir casting. Wear behavior of the brass composite pin was analyzed by disc tribometer. Wear characterization studies and confirmation of elemental composition are investigated through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) respectively. The worn surface of the synthesized brass composite was analyzed using atomic force microscopy (AFM). The aim of the investigation is to examine the surface morphology of the worn specimen. Based on the input constraints, the wear rate ranges from 0.0135 to 0.0893 mm3/min. The applied load is the predominant factor in the wear rate (83.75%). Sliding velocity has a minor effect on wear rate (1.06%). The improved surface roughness of 15.27 nm was produced on the worn surface. The novelty of the research work is to study the various surface parameters of the worn surface, such as roughness average, root mean square roughness, maximum height of the roughness, skewness, and kurtosis. These parameters were analyzed at different wear-worn surfaces of the synthesized brass composite. The wear-worn surface was deeply investigated and incorporated with SEM and AFM analysis. 

/pdf/wear-behavior-of-brass-based-composite-reinforced-with-sic-2p55jxlr.pdf

E. Mohan

Papers

Experimental Investigation on Boring Tool Vibration Control Using MR Fluid Damper

Wear Behavior of Brass Based Composite Reinforced with SiC and Produced by Stir Casting Process

Effect of Heterogeneous Nucleation of B4c and Bn on Metallographic and Mechanical Behaviour of Mg-Al-Zn Alloy Hybrid Composites

Optimization and Machinability behaviours on synthesized copper tin composite