Vibration Testing of Novel Engine Mount: Technical Note

Author(s):  
M.Ravi Teja Reddy ◽  
V. Jayakumar ◽  
D. Santhoshkumar ◽  
A. Muniappan

In order to isolate the vibrations in rotating machineries, engine mounts are used. In this paper, a novel engine mount that is specially designed using fluorocarbon material is experimentally assessed for an improved performance with an existing rubber based engine mount. The changes are made in the dimensions of the existing engine mount for better vibration absorption. Experimental results have shown a considerable benefit in vibration suppression by the engine mount using fluorocarbon more than the ones using rubber.

Author(s):  
Payam Soltani ◽  
Christophe Pinna ◽  
David J Wagg ◽  
Roly Whear

Hydraulic engine mounts are key elements in an automotive vehicle suspension system that typically experience a change of their designed function during their working lifetime due to progressive material ageing, primarily from the elastomeric component. Ageing of the engine mount, resulting from severe and continuous mechanical and thermal loads, can have a detrimental impact on the ride and comfort and long-term customer satisfaction. This paper introduces a new practical methodology for simulating the ageing behaviour of engine mounts resulting from the change in properties of their elastomeric main spring component. To achieve this, a set of dynamic mechanical thermal analysis tests were conducted on elastomeric coupons taken from a set of engine mounts with different service and ageing conditions. These experimental results were used to characterise the change in mechanical response of the elastomer and to build up an empirical elastomer ageing model. Then a finite element model of the main spring was developed that used the elastomer ageing model so that the ageing behaviour of the engine mount could be simulated. The resulting ageing model was verified by using experimental results from a second batch of ex-service engine mounts. The results show an increasing trend of the vertical static stiffness of the engine mounts with distance travelled (or age) up to a certain distance (approximately 95,000 km). The trend is then reversed and a softening effect is observed. Moreover, the results reveal that both the maximum stiffness value and the distance travelled at the peak stiffness decrease as the temperature increases.


Author(s):  
Omid Mohareri ◽  
Siamak Arzanpour

The hydraulic engine mount (HEM) has been designed to provide a vibration isolation characteristic to control road and engine induced vibrations in vehicles by using two fluid passages known as decoupler and inertia track. These types of engine mounts are known for their best noise, vibration, and harshness (NVH) suppression performance among other different types of engine mounts. However, a low cost technique to recycle the dissipated energy of the system in the process of vibration suppression is significantly advantageous. A novel design structure in which the decoupler is replaced with a water turbine to capture and restore the vibration energy of the system is presented in this paper. The turbine design and selection has been done based on the upper and lower chamber pressures and the fluid flow rates in the system’s resonant frequency. The mount vibration isolation and energy generation performance is studied in both frequency and time domains. The simulation results demonstrate that a considerable amount of energy can be harvested from the engine vibration sources. This recent study demonstrates a novel energy harvesting technique in vehicles that require minimum design modifications of conventional hydraulic mounts.


Author(s):  
D. Santhoshkumar ◽  
V. Jayakumar ◽  
M.Ravi Teja Reddy ◽  
A. Muniappan

Vibrations are caused in an engine due to the continuous motion of reciprocating and rotating parts. Engine mounts are used as the vibration isolators from the engine to frame. The absorbing capacity of the mounts should be large enough to withstand the vibrational force for longer periods. Engine mount’s strength depends upon the material and the type of the design. The modelling and assembly of the engine mount is done using solidworks and the analysis of the mount is done using Ansys software. Modal analysis is done on the engine mount at working frequency. With the results obtained, factor of safety is calculated and it is compared with the existing mount. The proposed engine mount model results in encouraging factor of safety value.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph K. E. Ortega ◽  
Revathi P. Mohan ◽  
Cindy M. Munoz ◽  
Shankar Lalitha Sridhar ◽  
Franck J. Vernerey

AbstractThe sporangiophores of Phycomyces blakesleeanus have been used as a model system to study sensory transduction, helical growth, and to establish global biophysical equations for expansive growth of walled cells. More recently, local statistical biophysical models of the cell wall are being constructed to better understand the molecular underpinnings of helical growth and its behavior during the many growth responses of the sporangiophores to sensory stimuli. Previous experimental and theoretical findings guide the development of these local models. Future development requires an investigation of explicit and implicit assumptions made in the prior research. Here, experiments are conducted to test three assumptions made in prior research, that (a) elongation rate, (b) rotation rate, and (c) helical growth steepness, R, of the sporangiophore remain constant during the phototropic response (bending toward unilateral light) and the avoidance response (bending away from solid barriers). The experimental results reveal that all three assumptions are incorrect for the phototropic response and probably incorrect for the avoidance response but the results are less conclusive. Generally, the experimental results indicate that the elongation and rotation rates increase during these responses, as does R, indicating that the helical growth steepness become flatter. The implications of these findings on prior research, the “fibril reorientation and slippage” hypothesis, global biophysical equations, and local statistical biophysical models are discussed.


Author(s):  
Sudhir Kaul ◽  
Anoop K. Dhingra ◽  
Timothy G. Hunter

This paper presents a comprehensive model to capture the dynamics of a motorcycle system in order to evaluate the quality of vibration isolation. The two main structural components in the motorcycle assembly - the frame and the swing-arm - are modeled using reduced order finite element models; the power-train assembly is modeled as a six degree-of-freedom (DOF) rigid body connected to the frame through the engine mounts and to the swing-arm through a shaft assembly. The engine mounts are modeled as tri-axial spring-damper systems. Models of the front-end assembly as well as front and rear tires are also included in the overall model. The complete vehicle model is used to solve the engine mount optimization problem so as to minimize the total force transmitted to the frame while meeting packaging and other side constraints. The mount system parameters - stiffness, position and orientation vectors - are used as design variables for the optimization problem. The imposed loads include forces and moments due to engine imbalance as well as loads transmitted due to irregularities in the road surface through the tire patch.


Author(s):  
A. R. Ohadi ◽  
G. Maghsoodi

In this paper, vibration behavior of engine on nonlinear hydraulic engine mount including inertia track and decoupler is studied. In this regard, after introducing the nonlinear factors of this mount (i.e. inertia and decoupler resistances in turbulent region), the vibration governing equations of engine on one hydraulic engine mount are solved and the effect of nonlinearity is investigated. In order to have a comparison between rubber and hydraulic engine mounts, a 6 degree of freedom four cylinders V-shaped engine under inertia and balancing masses forces and torques is considered. By solving the time domain nonlinear equations of motion of engine on three inclined mounts, translational and rotational motions of engines body are obtained for different engine speeds. Transmitted base forces are also determined for both types of engine mount. Comparison of rubber and hydraulic mounts indicates the efficiency of hydraulic one in low frequency region.


Author(s):  
Gholamhossein Adham ◽  
Seied Omid Keyhan ◽  
Hamid Reza Fallahi ◽  
Heliya Ziaei ◽  
Mohan Thomas

Abstract Background Nasal sill is one of the components of the alar ring, affecting the esthetic outcomes of rhinoplasty; accordingly, we developed a novel technique to adjust defects in this area and compared it with the available techniques. Methods Our technique was based on creating a tunnel access to the nasal sill area through an incision made in the lower third of the columella using the open approach or through a nostril base incision in patients, who underwent alar base reduction, followed by insertion of a cartilaginous graft into the marked defect area. Results A total number of 54 patients with a defect in the nasal sill area were included in this study. Thirty-one patients underwent open rhinoplasty with the sill approach from the lower third of the columella, while 23 patients underwent rhinoplasty with a nostril base approach for nasal sill augmentation procedure. There were no reports of patient dissatisfaction, infection, bleeding, sensory dysfunction, or remaining asymmetry of the sill area. Conclusion Based on the findings of the present study, this technique can be successfully used in reconstructing the nasal sill area with minimal complications and morbidity.


Author(s):  
Nejat Olgac ◽  
Martin Hosek

Abstract A novel active vibration absorption technique, the Delayed Resonator, has been introduced recently as a unique way of suppressing undesired oscillations. It suggests a control force on a mass-spring-damper absorber in the form of a proportional position feedback with a time delay. Its strengths consist of extremely simple implementation of the control algorithm, total vibration suppression of the primary structure against a harmonic force excitation and full effectiveness of the absorber in a semi-infinite range of disturbance frequency, achieved by real-time tuning. All this development work was done using the absolute displacements of the absorber in the feedback. These displacement measurements may be difficult to obtain and for some applications impossible. This paper deals with a substitute and easier measurement: the relative motion of the absorber with respect to the primary structure. Theoretical foundations for the Delayed Resonator (DR) are briefly recapitulated and its implementation on a single-degree-of-freedom primary structure disturbed by a harmonic force is introduced utilizing both absolute and relative position measurement of absorber mass. Methods for stability range analysis and transient behavior are presented. Properties acquired for the same system with these two different feedback are compared. Relative position measurement case is found to be more advantageous in most applications of the Delayed Resonator method.


2001 ◽  
Author(s):  
Giulio Grillo ◽  
Nejat Olgac

Abstract This paper presents an influence region analysis for an actively tuned vibration absorber, the Delayed Resonator (DR). DR is shown to respond to tonal excitations with time varying frequencies [1–3]. The vibration suppression is most effective at the point of attachment of the absorber to the primary structure. In this study we show that proper feedback control on the absorber can yield successful vibration suppression at points away from this point of attachment. The form and the size of such “influence region” strongly depend on the structural properties of the absorber and the primary system. There are a number of questions addressed in this paper: a) Stability of vibration absorption, considering that a single absorber is used to suppress oscillations at different locations. b) Possible common operating frequency intervals in which the suppression can be switched from one point on the structure to the others. A three-degree-of-freedom system is taken for as example case. One single DR absorber is demonstrated to suppress the oscillations at one of the three masses at a given time. Instead of an “influence region” a set of “influence points” is introduced. An analysis method is presented to find the common frequency interval in which the DR absorber operates at all three influence points.


Author(s):  
Yu Zhao ◽  
Masayoshi Tomizuka

Although input shaping is an effective approach for vibration suppression in a variety of applications, the time delay introduced is not desired. Current techniques to reduce the time delay can not guarantee zero delay or may cause non-smooth motion, which is harmful for the actuators. In order to address such issue, a modified zero time delay input shaping is proposed in this paper. Experimental results show the advantage of the proposed approach.


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