On the Effect of Cardboard Liners on Impact-Induced High Frequency Vehicular Driveline Vibrations

2007 ◽  
Author(s):  
Stephanos Theodossiades ◽  
Homer Rahnejat ◽  
Patrick Kelly
Keyword(s):  
Short Duration ◽  
High Frequency ◽  
Modern Trend ◽  
Component Level ◽  
Contact Behaviour ◽  
Foam Filled ◽  
High Frequency Vibrations ◽  
Metallic Wires ◽  
Noise Vibration ◽  
Fea Analysis

A typical driveline Noise, Vibration and Harshness (NVH) spectrum contains the contribution of a significant number of vibration components, ranging from a few Hz to several kHz. This is due to different NVH phenomena that have their causes in the contact behaviour of discrete driveline components. A short duration, audible, high frequency, elastoacoustic phenomenon, which occurs as a load reversal in the presence of lashes in the driveline, is onomatopoeically known in industry as clonk (300–5,000 Hz). Its short duration acts as an impulse that excites a large number of structural modes of the lightly damped driveline system. The above phenomenon has become a major concern to automobile manufacturers in recent years with the modern trend of reducing inertial effects in powertrain systems by use of materials of lower elastic moduli and thinner sections. The most common approach in industry to reduce the radiated clonk noise is by using palliatives, such as metallic wires, foam-filled driveshafts, the Dual Mass Flywheel (DMF) and cardboard liners. However, the mechanisms of vibration and noise reduction that the above palliatives introduce have not been fully understood yet, as these are rather used in an empirical manner. This paper investigates the effect of cardboard liners on the high frequency driveline response, by a combined study of FEA analysis at component level and experimental measurements in a drivetrain rig. The results reveal that cardboard liners reduce the severity of the driveline high frequency vibrations, as well as the number of the driveshafts’ structural modes that are excited by remote impacting of the drivetrain components through their lash zones. The predicted and observed effect of the cardboard liners shows good conformance with the existing literature.

Energy Absorption of Vibration in the Hand for Higher Frequencies

1996 ◽  
Vol 15 (2) ◽  
pp. 71-79 ◽  
Author(s):  
Anna SöRensson ◽  
Lage Burström
Keyword(s):  
Energy Absorption ◽  
High Frequency ◽  
Measurement Method ◽  
Vibration Energy ◽  
Frequency Range ◽  
Measurement And Analysis ◽  
Method Of Measurement ◽  
High Frequency Vibrations ◽  
Noise Vibration ◽  
Male Subjects

The aim of this study has been to develop a measurement method to study the absorption of vibration energy on exposure to high frequency vibrations. The developed measurement method consists of specially constructed equipment for measurement and analysis of the subject's absorption of vibration energy. In this study the energy absorption from the exposure to white noise vibration within the frequency-range 20 to 5000 Hz has been studied. Five female and five male subjects were involved in this study. The results show that the developed method of measurement works satisfactorily and gives reliable results for the energy absorption within the frequency-range 20 to 4000 Hz. Furthermore, the results show that the subjects absorb vibration energy even for frequencies above 1000 Hz. The results also show that the energy absorption is dependent upon factors such as gender, the level of the vibration and the frequency.

Simulation of vibration piercing of pipe blank at press

2020 ◽  
Vol 76 (11) ◽  
pp. 1128-1138
Author(s):  
S. R. Rakhmanov
Keyword(s):  
High Frequency ◽  
Deformation Zone ◽  
Pipe Blank ◽  
Equipment Operation ◽  
Metal Deformation ◽  
Technological Tool ◽  
High Frequency Vibrations ◽  
Pipe Blanks ◽  
Wave Phenomena

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.

Analytical Solution for Rotational Rub-Impact Plate Under Thermal Shock

2016 ◽  
Vol 32 (3) ◽  
pp. 297-311
Author(s):  
T.-Y. Zhao ◽  
H.-Q. Yuan ◽  
B.-B. Li ◽  
Z.-J. Li ◽  
L.-M. Liu
Keyword(s):  
Thermal Shock ◽  
High Frequency ◽  
Equations Of Motion ◽  
Low Frequency ◽  
Cantilever Plate ◽  
Analysis Method ◽  
Multiple Frequency ◽  
Width Direction ◽  
Blade Tip ◽  
High Frequency Vibrations

AbstractThe analysis method is developed to obtain dynamic characteristics of the rotating cantilever plate with thermal shock and tip-rub. Based on the variational principle, equations of motion are derived considering the differences between rubbing forces in the width direction of the plate. The transverse deformation is decomposed into quasi-static deformation of the cantilever plate with thermal shock and dynamic deformation of the rubbing plate under thermal shock. Then deformations are obtained through the calculation of modal characteristics of rotating cantilever plate and temperature distribution function. Special attention is paid to the influence of tip-rub and thermal shock on the plate. The results show that tip-rub has the characteristics of multiple frequency vibrations, and high frequency vibrations are significant. On the contrary, thermal shock shows the low frequency vibrations. The thermal shock makes the rubbing plate gradually change into low frequency vibrations. Because rub-induced vibrations are more complicated than those caused by thermal shock, tip-rub is easier to result in the destruction of the blade. The increasing friction coefficient intensifies vibrations of the rubbing plate. Minimizing friction coefficients can be an effective way to reduce rub-induced damage through reducing the surface roughness between the blade tip and the inner surface of the casing.

Convection of a binary mixture under high-frequency vibrations

2013 ◽  
Vol 341 (4-5) ◽  
pp. 477-482 ◽  
Author(s):  
Sergey M. Ishutov ◽  
Bela I. Myznikova ◽  
Boris L. Smorodin
Keyword(s):  
Binary Mixture ◽  
High Frequency ◽  
High Frequency Vibrations

scholarly journals Erratum to: Acute and cumulative effects of focused high-frequency vibrations on the endocrine system and muscle strength

2013 ◽  
Vol 113 (11) ◽  
pp. 2871-2871 ◽  
Author(s):  
Pierpaolo Iodice ◽  
Rosa Grazia Bellomo ◽  
Glaugo Gialluca ◽  
Giorgio Fanò ◽  
Raoul Saggini
Keyword(s):  
Muscle Strength ◽  
High Frequency ◽  
Endocrine System ◽  
Cumulative Effects ◽  
High Frequency Vibrations

Experimental support for the flowing aether concept of gravity

2021 ◽  
Vol 34 (4) ◽  
pp. 538-547
Author(s):  
Duncan W. Shaw
Keyword(s):  
Present Article ◽  
High Frequency ◽  
Experimental Support ◽  
High Frequency Vibrations ◽  
Two Sides

The article of Apffel et al. [Nature 585, 48 (2020)] reported on an experiment that produced the sight of two miniature sailboats floating upside down to each other on the two sides of a layer of glycerol that was levitated by high frequency vibrations. The vessel on the underside of the glycerol is a remarkable display of the results of simulated gravity caused by vibrations. The present article considers this and other experiments on simulated gravity and finds that they provide support for the flowing aether concept of the cause of gravity.

Ultrasonic Cutting of Switchgrass and Miscanthus Stems

2018 ◽  
Vol 34 (2) ◽  
pp. 343-353
Author(s):  
A. Bulent Koc Koc ◽  
Bo Liu
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
High Frequency ◽  
Cutting Speed ◽  
Particle Size Reduction ◽  
Element Analysis ◽  
Cutting Energy ◽  
High Frequency Vibrations ◽  
Ultrasound Assisted ◽  
Ultrasonic Cutting

Abstract. Ultrasound-assisted cutting has been used to cut materials with high precision, improved quality and reduced cutting forces. The research objective was to investigate the effects of high-frequency vibrations on the cutting force and cutting energy of switchgrass and miscanthus stems. Laboratory experiments were conducted on individual biomass stems at cutting speeds between 3 and 400 mm/s. An experimental cutting system with an ultrasound generator, an ultrasonic blade, a load cell, and a data acquisition system was developed. The custom designed blade was 5-cm wide and vibrated at 19.551 kHz with 2.8 µm tip vibration amplitude. There were significant measured differences in the cutting forces and cutting energies between conventional cutting and ultrasonic cutting of switchgrass and miscanthus stems (p < 0.05). These results suggest that the use of high-frequency vibrations reduce cutting force and cutting energy of both switchgrass and miscanthus stems. Ultrasound-assisted cutting reduced the cutting energy of switchgrass by 66.85% at 100 mm/s and miscanthus by 80.58% at 30 mm/s. However, ultrasonic cutting did not have a significant effect on the cutting force and cutting energy when the cutting speed was equal to or greater than the blade tip vibration speed. The results of this research should be useful for adapting the ultrasonic technology in biomass harvesting, particle size reduction, and processing equipment. Keywords: Biomass, Blades, Energy, Finite element analysis, Miscanthus, Switchgrass, Ultrasonics.

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