scholarly journals Presentation of an Approach on Determination of the Natural Frequency of Human Lumbar Spine Using Dynamic Finite Element Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Fan Ruoxun ◽  
Liu Jie ◽  
Liu Jun ◽  
Wang Weijun
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Natural Frequency ◽  
Excitation Frequency ◽  
Element Model ◽  
Mechanical Parameters ◽  
Element Analysis ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Human Lumbar Spine

Occurring resonance may negatively affect the health of the human lumbar spine. Hence, vibration generated in working and living environments should be optimized to avoid resonance when identifying the natural frequency of the human lumbar spine. The range of the natural frequency of the human lumbar spine has been investigated, but its specific numerical value has not been determined yet. This study aimed at presenting an approach based on resonance for predicting the specific numerical value of the natural frequency of the human lumbar spine. The changes in the numerical fluctuation amplitudes and the cycles of lumbar mechanical parameters during resonance are greater than those during nonresonant vibration. Given that the range of the natural frequency has been identified, vibrations at different excitation frequencies within this range can be applied in a human lumbar finite element model for dynamic finite element analysis. When the excitation frequency is close to the natural frequency, resonance occurs, causing great changes in the numerical fluctuation amplitudes and the cycles of lumbar mechanical parameters. Therefore, the natural frequency of the lumbar finite element model could be back-calculated. Results showed that the natural frequency of the established model was 3.5 Hz. Meanwhile, the closer the excitation frequency was to the natural frequency, the greater the changes in the numerical fluctuation amplitudes and cycles in the parameters would be. This study presented an approach for predicting the specific numerical value of the natural frequency of the human lumbar spine. Identifying the natural frequency assists in finding preventive measures for lumbar injury caused by vibration and in designing the vibration source in working and living environments to avoid approximating to the natural frequency of the human lumbar spine.

Dynamic Behavior on Emergency Landing of Light Aircraft with Occupant Restraint System

2012 ◽  
Vol 591-593 ◽  
pp. 2513-2517
Author(s):  
Lin Yin Luo ◽  
Yan Bin He ◽  
Xuan Liu ◽  
Xiao Hu Yao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Restraint System ◽  
Element Analysis ◽  
Occupant Restraint System ◽  
Head Injury Criterion ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Safety Design

In the case of aircraft emergency landing, occupants’ safety analysis and research is one of the indispensable links in the verification of airworthiness safety. However, traditional experimental methods is time-consuming, complex and costly, seriously affect the development of new models to market. This paper established a finite element model of the full-size aircraft cockpit according to a certain type of amphibious light aircraft, and adding the dummy and safety belt occupant restraint system finite element model on this basis. In accordance with the requirements of CCAR-23 test conditions, using large dynamic finite element analysis software LS-DYNA numerical simulation was processed to study this aircraft’s emergency landing procedure. This paper investigated the dynamic response of the dummy and head injury criterion (HIC) value etc. The results provide certain reference for aircraft emergency landing safety design.

The Dynamic Finite Element Analysis for Gravitational Settling of a Sunken Ship in Soft Foundation

2014 ◽  
Vol 638-640 ◽  
pp. 605-608
Author(s):  
Zhong Xiao ◽  
Yuan Zhan Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Large Amplitude ◽  
Element Model ◽  
Element Analysis ◽  
Gravitational Settling ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Soft Foundation ◽  
Compression Region

The calculation for the gravitational settling and position of a sunken ship can provide important information for a reasonable salvage program. A 3D elastic-plastic dynamic finite element model was established to calculate the gravitational settling of a sunken ship in soft foundation of Tianjin port in China. The results showed that a large amplitude settlement had happened in previous seconds, and then settlement tended to be stable. The stable value was in keeping with the field observation value. Besides, a collapse pit on the top surface of soils under the hull induced by the gravity of dredge was formed while soils around the compression region were raised. Moreover, the strain value increased rapidly in previous seconds which induced a large amplitude settlement of the ship and then tended to be stable.

The Finite Element Analysis and Optimization for the Grinder Based on the Joint Surface

2013 ◽  
Vol 281 ◽  
pp. 165-169 ◽  
Author(s):  
Xiang Lei Zhang ◽  
Bin Yao ◽  
Wen Chang Zhao ◽  
Ou Yang Kun ◽  
Bo Shi Yao
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Element Model ◽  
Joint Surface ◽  
Weak Links ◽  
Response Analysis ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Harmonic Response Analysis ◽  
Grinding Machine

Establish the finite element model for high precision grinding machine which takes joint surface into consideration and then carrys out the static and dynamic analysis of the grinder. After the static analysis, modal analysis and harmonic response analysis, the displacement deformation, stress, natural frequency and vibration mode could be found, which also helps find the weak links out. The improvement scheme which aims to increase the stiffness and precision of the whole machine has proposed to efficiently optimize the grinder. And the first natural frequency of the optimized grinder has increased by 68.19%.

The Dynamic Finite Element Analysis of Shearer’s Running Gear Based on LS-DYNA

2011 ◽  
Vol 402 ◽  
pp. 753-757 ◽  
Author(s):  
Hai Long Tong ◽  
Zhong Hai Liu ◽  
Li Yin ◽  
Quan Jin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Simulation Analysis ◽  
Dynamic Contact ◽  
Secondary Development ◽  
Element Analysis ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Element Theory ◽  
Meshing Process

Base on contact kinetics finite element theory, proceed secondary development of road wheel and pin mesh’s nonlinear dynamic contact analysis in LS-DYNA module, and carry out contrast of simulation analysis, achieved stress, strain and dynamic identities that caused by meshing impact in the whole meshing process, accord with practice, can instruct product practice design.

Dynamic Finite Element Analysis of a Cylindrical Roller Bearing

2011 ◽  
Vol 143-144 ◽  
pp. 437-442
Author(s):  
Bao Hong Tong ◽  
Yin Liu ◽  
Xiao Qian Sun ◽  
Xin Ming Cheng
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Roller Bearing ◽  
Element Analysis ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Simulation Results ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

A dynamic finite element analysis model for cylindrical roller bearing is developed, and the complex stress distribution and dynamic contacting nature of the bearing are investigated carefully based on ANSYS/LS-DYNA. Numerical simulation results show that the stress would be bigger when the element contacting with the inner or outer ring than at other times, and the biggest stress would appear near the area that roller contacting with the inner ring. Phenomenon of stress concentration on the roller is found to be very obvious during the operating process of the bearing system. The stress distributions of different elements are uneven on the same side surface of roller in its axis direction. Numerical simulation results can give useful references for the design and analysis of rolling bearing.

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