Research of Frame Optimization Technology Based on SIMP

2012 ◽  
Vol 468-471 ◽  
pp. 2802-2805
Author(s):  
Xue Tao Huang ◽  
Liang Gu ◽  
Wei Wei Lv
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Ride Comfort ◽  
Low Frequency ◽  
Frame Structure ◽  
Resonance Phenomenon ◽  
Impact Factors ◽  
First Order ◽  
Low Frequency Vibration ◽  
External Motivation

The low frequency vibration of vehicle is very popular. The vibration can reduce ride comfort and cause early damage of part, so we must do something to reduce it. But the vibration has more complex impact factors, so it is very difficult to solve it. This paper has studied a new method to reduce it. It has studied the natural frequencies of the frame on the platform of OptiStruct software. Through the research, we find that the first order mode natural frequency of the frame is close to the external motivation, which is caused by moving unbalance of wheels. It leads to the resonance phenomenon, which is the main reason for vehicle low frequency vibration. In order to improve the vibration, this paper has researched the principle of SIMP topology optimization technology, and searched for the topology frame structure, whose first mode natural frequency is far away from the external motivation. Finally, this paper shows a new design for the frame, which reduces the low frequency vibration of vehicle greatly.

Analysis of Vibro-Acoustic Modulations in Nonlinear Acoustics Used for Impact Damage Detection - Numerical and Experimental Study

2013 ◽  
Vol 558 ◽  
pp. 341-348 ◽  
Author(s):  
Łukasz Pieczonka ◽  
Andrzej Klepka ◽  
Wieslaw Jerzy Staszewski ◽  
Tadeusz Uhl ◽  
Francesco Aymerich
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Composite Plate ◽  
Natural Frequencies ◽  
Impact Damage ◽  
Low Frequency ◽  
Fe Modeling ◽  
Low Frequency Vibration ◽  
Frequency Excitation ◽  
Nonlinear Acoustic

The paper investigates experimentally the effect of low-frequency vibration on nonlinear vibro-acoustic wave modulations applied to the detection of Barely Visible Impact Damage (BVID) in a composite plate. Finite Element (FE) modeling was used in a pretest stage to identify different motion scenarios of delaminated surfaces and relate them to natural frequencies of the damaged plate. In particular the opening-closing and frictional sliding actions of the defected interfaces have been considered. Subsequently, the identified frequencies have been used for low frequency excitation in nonlinear acoustic experiments on a composite plate with impact damage.

Enhanced ride comfort using nonlinear seat suspension with high-static-low-dynamic stiffness

2020 ◽  
Vol 51 (4-5) ◽  
pp. 63-76 ◽  
Author(s):  
Chun Cheng ◽  
Yan Hu ◽  
Ran Ma
Keyword(s):  
Ride Comfort ◽  
Structural Parameters ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Low Frequency ◽  
Coupled Model ◽  
Human Model ◽  
Vehicle Speed ◽  
Seat Suspension ◽  
Low Frequency Vibration

To attenuate the low-frequency vibration transmitted to the driver, a nonlinear seat suspension with high-static-low-dynamic stiffness is designed. First, the force and stiffness characteristics are derived. The nonlinear suspension can achieve the quasi-zero stiffness at the static equilibrium position when the structural parameters are properly designed. Then, a car-seat-human coupled model which consists of a quarter car model, a seat suspension, and a 4 degree-of-freedom human model is established to predict the biodynamic response of the driver. Finally, the isolation performance of the high-static-low-dynamic stiffness seat suspension under two typical road excitations is evaluated separately based on the numerical method. The effects of stiffness ratio, damping ratio, and vehicle speed on the ride comfort are investigated. The results showed that the nonlinear seat suspension outperforms the equivalent linear counterpart and can achieve the best ride comfort when the quasi-zero stiffness condition is satisfied.

Effect of Low-Frequency Vibration on Human Body in Standing Position Exposed to Railway Vehicle

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Rajesh Govindan ◽  
Suraj Prakash Harsha
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Human Body ◽  
Low Frequency ◽  
Vertical Direction ◽  
Standing Position ◽  
Mode Shapes ◽  
Railway Vehicle ◽  
Lateral Direction ◽  
Low Frequency Vibration

In this paper, the dynamic characteristics of the human body were investigated by developing a 3-D finite element model based on 50th percentile anthropometric data for a 54 kg Indian male subject in standing position by considering human body segments as an ellipsoid. The finite element modal analysis is carried out to extract several low-frequency vibration modes and its vibration mode shapes were presented in this paper. The results show that the lowest natural frequency of the standing passenger model occurs in the fore-and-aft direction. The second natural frequency occurs in the lateral direction and the first order natural frequency of the standing passenger model in the vertical direction occurs at 5.379 Hz. The model will be helpful to predict the vibration response of human body under various vibration environment encounters in the railway vehicle.

scholarly journals Low-Frequency Vibration Testing of Huge Bucket Wheel Excavator Based on Step-Decay Signals

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Y. Z. Jiang ◽  
C. J. Liu ◽  
X. J. Li ◽  
K. F. He ◽  
D. M. Xiao
Keyword(s):  
Fatigue Life ◽  
Natural Frequencies ◽  
Low Frequency ◽  
Vibration Testing ◽  
Testing Methods ◽  
Testing Method ◽  
Low Frequency Vibration ◽  
Free Decay ◽  
Supporting Rollers ◽  
Excitation Method

The low-frequency vibration of the bucket wheel excavator has an important impact on the fatigue life of the structures. For conventional vibration testing methods, it is difficult and expensive to excite the overall low-frequency vibration of the whole machine. Hence, in this paper, the excitation method that uses the belt-supporting rollers on the boom as an exciter is tried to excite the low-frequency vibration, so that the low natural frequencies can be identified by Fourier transforming the free decay signals caused by the sudden power off. By this method, the first five natural frequencies are obtained, and the results are verified through corresponding computational numerical model of the bucket wheel excavator. It can be concluded that the proposed testing method can achieve the same accuracy but is much more convenient and costs less than existing methods.

The Experiments of Cantilever Piezoelectric Vibrator Power Generation

2012 ◽  
Vol 236-237 ◽  
pp. 1368-1372
Author(s):  
Su Xiang Qian ◽  
Hong Sheng Hu ◽  
Li Xia Ge ◽  
Jia You Song
Keyword(s):  
Power Generation ◽  
Natural Frequency ◽  
Low Frequency ◽  
Experiment Research ◽  
Piezoelectric Vibrator ◽  
Piezoelectric Resonators ◽  
Low Frequency Vibration ◽  
Proper Mass

Papers on cantilever piezoelectric resonators experiment research in the low frequency vibration environment. The study proved that, to choose a proper mass can effectively regulate the cantilever piezoelectric vibrators natural frequency The more close to the incentive frequency and the natural frequency of piezoelectric vibrators, the better the results of piezoelectric vibrators power generation.

scholarly journals Vibration Analysis and Modeling of an Off-Road Vibratory Roller Equipped with Three Different Cab’s Isolation Mounts

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Vanliem Nguyen ◽  
Jianrun Zhang ◽  
Vanquynh Le ◽  
Renqiang Jiao
Keyword(s):  
Dynamic Model ◽  
Ride Comfort ◽  
Three Dimensional ◽  
Low Frequency ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Nonlinear Dynamic Model ◽  
Obvious Effect ◽  
Low Frequency Vibration ◽  
Power Spectral

This study proposes a dynamic model of the vibratory roller interacting with the off-road deformed terrain to analyze the low-frequency performance of three different cab’s isolation mounts under the different operating conditions. In order to evaluate the ride comfort of the vibratory roller with the different cab’s isolation mounts, a three-dimensional nonlinear dynamic model is established. The power spectral density (PSD) and the weighted root mean square (RMS) of acceleration responses of the vertical driver’s seat, cab’s pitch, and roll vibrations are chosen as objective functions in the low-frequency range. Contrastive analysis of low-frequency vibration characteristics of the vibratory roller with the traditional rubber mounts, the hydraulic mounts, and the pneumatic mounts is carried out. Experimental investigations are also used to verify the accuracy of models. The research results show that the hydraulic mounts have an obvious effect on mitigating the cab vibration and improving the ride comfort in comparison with the traditional rubber mounts and the pneumatic mounts.

Design, Analysis, and Experimental Studies of a Novel PVDF-Based Piezoelectric Energy Harvester With Beating Mechanisms

2014 ◽  
Author(s):  
Kuo-Shen Chen
Keyword(s):  
Natural Frequency ◽  
Energy Harvester ◽  
Piezoelectric Materials ◽  
Low Frequency ◽  
Major Barrier ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Low Frequency Vibration ◽  
High Efficient ◽  
The Future

Wireless sensor networks become increasingly important in modern life for structural health monitoring and other related applications. In these applications, due to their overall sensor populations and possible covered measurement areas, the replacement of batteries becomes a difficult and unrealistic task. As a result, energy harvesters to convert environment wasted vibration energy into electricity for powering those sensor nodes become important and many miniaturized device have been realized by using MEMS technology. In order to achieve optimal performance, the energy harvester must be operated at the resonance frequency. However, the vibration frequencies of environmental vibrations are usually much less than that of those miniaturizing energy harvesters and this fact could be a major barrier for energy harvesting performance. In this paper, a new piezoelectric energy scavenging concept is proposed and demonstrated to convert environmental vibrations into electricity. Unlike previous MEMS-based piezoelectric energy harvesters, which suffer from matching between environmental low frequency vibration and the much higher system natural frequency, this work proposes a novel beating design using polymer piezoelectric materials in collaborating with a beating mechanism. That is, by creating impact force via the low frequency vibration motion from the mechanism, it is possible to excite system natural frequency by the low frequency environmental vibrations and it is possible to operate the entire system at the natural frequency. This work contains details in presenting this idea, designing piezoelectric harvester systems with flexible PVDF elements, exploring their vibration characteristics, and energy accumulating strategies by using a capacitor with a full-bridged rectifiers or a boost conversion. By experimental characterization, the overall harvesting efficiency of the proposed design is much greater than that from the design without the beating mechanism. It indicates that the efficiency is significantly improved and the proposed translational design could potentially improve the future design approach for piezoelectric energy harvesters significantly. In summary, this preliminary study shows that it is a feasible scheme for the application of piezoelectric materials in harvesting electricity from environmental vibrations. Although this work is still in its initial phase, the results and conclusions of this work are still invaluable for guiding the development of high efficient piezoelectric harvesters in the future.

scholarly journals Prediction of Wind Velocity to Raise Vortex-Induced Vibration through a Road-Rail Bridge with Truss-Shaped Girder

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Seungtaek Oh ◽  
Sung-il Seo ◽  
Hoyeop Lee ◽  
Hak-Eun Lee
Keyword(s):  
Wind Tunnel ◽  
Natural Frequency ◽  
Wind Velocity ◽  
Vortex Shedding ◽  
Natural Frequencies ◽  
Wind Tunnel Test ◽  
Resonance Phenomenon ◽  
Vortex Induced Vibration ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency

Vortex-induced vibration (VIV) of bridges, related to fluid-structure interaction and maintenance of bridge monitoring system, causes fatigue and serviceability problems due to aerodynamic instability at low wind velocity. Extensive studies on VIV have been performed by directly measuring the vortex shedding frequency and the wind velocity for indicating the largest girder displacement. However, previous studies have not investigated a prediction of wind velocity to raise VIV with a various natural frequency of the structure because most cases have been focused on the estimation of the wind velocity and peeling-off frequency by the mounting structure at the fixed position. In this paper, the method for predicting wind velocity to raise VIV is suggested with various natural frequencies on a road-rail bridge with truss-shaped girder. For this purpose, 12 cases of dynamic wind tunnel test with different natural frequencies are performed by the resonance phenomenon. As a result, it is reasonable to predict wind velocity to raise VIV with maximum RMS displacement due to dynamic wind tunnel tests. Furthermore, it is found that the natural frequency can be used instead of the vortex shedding frequency in order to predict the wind velocity on the dynamic wind tunnel test. Finally, curve fitting is performed to predict the wind velocity of the actual bridge. The result is shown that predicting the wind velocity at which VIV occurs can be appropriately estimated at arbitrary natural frequencies of the dynamic wind tunnel test due to the feature of Strouhal number determined by the shape of the cross section.

The effect of bi-axial in-plane loads on the natural frequency of nano-plates

2017 ◽  
Vol 24 (19) ◽  
pp. 4513-4528 ◽  
Author(s):  
Seyed Ghasem Enayati ◽  
Morteza Dardel ◽  
Mohammad Hadi Pashaei
Keyword(s):  
Natural Frequency ◽  
Nonlocal Elasticity ◽  
Natural Frequencies ◽  
Plate Theory ◽  
Nonlocal Parameter ◽  
Nonlocal Elasticity Theory ◽  
Classical Plate Theory ◽  
First Order ◽  
Compressive Loads ◽  
Comprehensive Study

In this paper, natural frequencies of nano-plates subjected to two-sided in-plane tension or compressive loads, based on Eringen nonlocal elasticity theory and displacement field of first-order shear deformation plate theory (FSDT), are investigated. By considering total rotational variables as the two rotations due to bending and shear, another formulation form of FSDT nano-plate is achieved, that can simultaneously consider classical plate theory (CLPT) and FSDT. In a comprehensive study, the effects of different parameters such as a nonlocal parameter, aspect ratio, thickness to length ratio, mode number, boundary conditions and also length of nano-plate are examined on the dimensionless natural frequency. The results show that simultaneously applying two-sided tension and compressive in-plane loads changes frequency in a manner which is different to one-directional loading.

Beam design for voice coil motors used for energy harvesting purpose with low frequency vibrations: A finite element analysis

2016 ◽  
Vol 07 (03) ◽  
pp. 1640001 ◽  
Author(s):  
Hector A. Tinoco
Keyword(s):  
Finite Element ◽  
Energy Harvesting ◽  
Finite Element Model ◽  
Natural Frequency ◽  
Low Frequency ◽  
Voice Coil Motor ◽  
Element Model ◽  
Design Tool ◽  
Beam Design ◽  
Low Frequency Vibration

In this study, a numerical approach is established to design a beam coupled to a Voice Coil Motor (VCM) with the aim to maximize the displacement in the inductive transducer. A finite element model is developed to simulate a VCM with different beams applying a harmonic analysis. The VCM is extracted from a recycled hard disk drive (HDD) and a parametric modal analysis is performed to identify the material parameters of the HDD and the beam. These parameters are obtained comparing the real vibration modes and natural frequencies (VCM-beam) with those determined from the finite element model. A numerical-experimental case study is carried out to demonstrate that if a beam is designed for a specific low frequency vibration between 0 and [Formula: see text], the displacements are maximized in the VCM. For this purpose, real acceleration measurements taken from three individuals are used to provide the vibration signals in the numerical model. A beam is designed for one of the individuals using the natural frequency values determined from the measured signals. Results show that the displacements are maximized in the model which coincides with the natural frequency of the chosen individual. The main purpose of this research is to establish a design tool for energy harvesting purposes with VCM based on low frequency vibration sources as for example gait motions.

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