scholarly journals Parameter Equivalent Method of Stator Anisotropic Material Based on Modal Analysis

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4257 ◽  
Author(s):  
Zeyu Zhang ◽  
Zhiyong Jiao ◽  
Hongbing Xia ◽  
Yuhan Yao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Anisotropic Material ◽  
Element Model ◽  
Correction Method ◽  
Stator Core ◽  
Modal Frequency ◽  
Material Parameters ◽  
The Relationship ◽  
Parameter Correction

Accurate calculation of the vibration mode and natural frequency of a motor stator is the basis for reducing motor noise and vibration. However, the stator core and winding material parameters are difficult to determine, posing issues which result in modal calculation bias. To address the problem of calibrating the stator material parameters, we developed a parameter correction method based on modal frequency. First, the stator system was simplified to build a stator system finite element model. Secondly, the relationship between modal frequency and material parameters was analyzed by finite element software, the relationship between modal frequency and material parameters was derived, and the anisotropic material parameter correction method was summarized. Finally, a modal experiment was carried out by the hammering method, and the simulation and experimental errors were within 3%, which verified the accuracy of the finite element model. The proposed correction method of anisotropic material can quickly determine the stator material parameters, and the stator core and winding anisotropic material can ensure the accuracy of the modal analysis.

scholarly journals Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue

2021 ◽  
Author(s):  
Zwelihle Ndlovu ◽  
Dawood Desai ◽  
Thanyani Pandelani ◽  
Harry Ngwangwa ◽  
Fulufhelo Nemavhola
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Test Data ◽  
Element Model ◽  
Finite Element Models ◽  
Anisotropic Model ◽  
Material Models ◽  
Material Parameters ◽  
Constitutive Parameters

This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.

scholarly journals Dynamic Analysis of Tapered Thin-Walled Beams Using Spectral Finite Element Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yiping Shen ◽  
Zhijun Zhu ◽  
Songlai Wang ◽  
Gang Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wind Turbine ◽  
Element Model ◽  
Rotor Blades ◽  
Mode Shapes ◽  
Modal Frequency ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Spectral Finite Element

Tapered thin-walled structures have been widely used in wind turbine and rotor blade. In this paper, a spectral finite element model is developed to investigate tapered thin-walled beam structures, in which torsion related warping effect is included. First, a set of fully coupled governing equations are derived using Hamilton’s principle to account for axial, bending, and torsion motion. Then, the differential transform method (DTM) is applied to obtain the semianalytical solutions in order to formulate the spectral finite element. Finally, numerical simulations are conducted for tapered thin-walled wind turbine rotor blades and validated by the ANSYS. Modal frequency results agree well with the ANSYS predictions, in which approximate 30,000 shell elements were used. In the SFEM, one single spectral finite element is needed to perform such calculations because the interpolation functions are deduced from the exact semianalytical solutions. Coupled axial-bending-torsion mode shapes are obtained as well. In summary, the proposed spectral finite element model is able to accurately and efficiently to perform the modal analysis for tapered thin-walled rotor blades. These modal frequency and mode shape results are important to carry out design and performance evaluation of the tapered thin-walled structures.

scholarly journals Curvature reduces bending strains in the quokka femur

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3100 ◽  
Author(s):  
Kyle McCabe ◽  
Keith Henderson ◽  
Jess Pantinople ◽  
Hazel L. Richards ◽  
Nick Milne
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Linear Relationship ◽  
Strain Gradient ◽  
Stance Phase ◽  
Element Model ◽  
Knee Extensors ◽  
Bending Strain ◽  
Biarticular Muscles ◽  
The Relationship

This study explores how curvature in the quokka femur may help to reduce bending strain during locomotion. The quokka is a small wallaby, but the curvature of the femur and the muscles active during stance phase are similar to most quadrupedal mammals. Our hypothesis is that the action of hip extensor and ankle plantarflexor muscles during stance phase place cranial bending strains that act to reduce the caudal curvature of the femur. Knee extensors and biarticular muscles that span the femur longitudinally create caudal bending strains in the caudally curved (concave caudal side) bone. These opposing strains can balance each other and result in less strain on the bone. We test this idea by comparing the performance of a normally curved finite element model of the quokka femur to a digitally straightened version of the same bone. The normally curved model is indeed less strained than the straightened version. To further examine the relationship between curvature and the strains in the femoral models, we also tested an extra-curved and a reverse-curved version with the same loads. There appears to be a linear relationship between the curvature and the strains experienced by the models. These results demonstrate that longitudinal curvature in bones may be a manipulable mechanism whereby bone can induce a strain gradient to oppose strains induced by habitual loading.

Accuracy and Robustness Analysis of Geometric Finite Element Model Updating Approach for Material Parameters Identification in Transient Dynamic

2018 ◽  
Vol 16 (01) ◽  
pp. 1850084 ◽  
Author(s):  
Clément Touzeau ◽  
Benoit Magnain ◽  
Quentin Serra ◽  
Éric Florentin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Numerical Test ◽  
Robustness Analysis ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Transient Dynamic ◽  
Material Parameters ◽  
Material Parameters Identification

We study the accuracy and the robustness of the Geometrical Finite Element Model Updating method proposed in Touzeau et al. [Touzeau, C., Magnain, B., Emile, B., Laurent, H. and Florentin, E. (2016) “Identification in transient dynamic using a geometry-based cost function in finite element model updating method,” Finite Elements Anal. Des. 122, 49–60]. In this work, the method is applied to transient dynamic in finite transformations to identify mechanical material parameters. A stochastic approach is performed to determine accuracy and robustness. The method is illustrated on numerical test cases and compared to a classical FEMU method. Uncertainties on the loading are taken into account in the identification using an original approach.

Establishment Method of the Simplified Model for Research on the Crashworthiness of B-Pillar in Side Impact

2014 ◽  
Vol 635-637 ◽  
pp. 502-506 ◽  
Author(s):  
Wei Min Zhuang ◽  
Qin Hua Xu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
High Accuracy ◽  
Side Impact ◽  
Simplified Model ◽  
Body Parts ◽  
Establishment Method ◽  
Short Time ◽  
The Relationship

In order to improve the efficiency of the calculation of the whole car side impact finite element model,simplified model often used in research of B-pillar in passenger car. It is critical to establish a high accuracy simplified model in a short time. The relationship between the energy absorption of body parts and the calculation accuracy of simplified model was analyzed,and the result can be used as a guide for the establishment of simplified model.

Study on Bearing Behaviors of Bolted Joints in Composite Laminates

2013 ◽  
Vol 652-654 ◽  
pp. 1509-1513
Author(s):  
Tao Huang ◽  
Zhe Su
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Finite Element Model ◽  
Composite Laminates ◽  
Element Model ◽  
Bolted Joints ◽  
Stress And Strain ◽  
Bolted Joint ◽  
Bearing Stress ◽  
The Relationship

An experimental investigation was conducted to determine the bearing stress of single-lap double bolted composite joints. The bearing stress of a group of specimen was presented and the relationship between the stress and strain was obtained. The experimental results show that the damage of the bolted joints was a progressive process; and the ultimate bearing stress depends not only on the laminates’ strength but also on the bolt strength. A finite element model was created based on the bolted joint specimen to simulate the loading – displacement response. The numerical results verified the experiment results qualitatively.

Simulation Analysis of Scour Impacts on the Dynamic Properties of a Bridge Structure

2013 ◽  
Vol 663 ◽  
pp. 27-30
Author(s):  
Yi Bo Li ◽  
Bin Peng ◽  
Wei Zheng ◽  
Rong Liu Gu ◽  
Chao Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Water Level ◽  
Simulation Analysis ◽  
Dynamic Properties ◽  
Element Model ◽  
Scour Depth ◽  
Bridge Structure ◽  
State Highway ◽  
The Relationship

Many damages of bridge are caused by scour. This paper tries to find out the relationship between the changes of dynamic properties of bridges and scour. The influence of scour on the Mississippi State Highway 33 Bridge is analyzed considering 2 factors, the scour depth and the water level. A Finite Element model is used to simulate the vibration of the bridge under scour. The results reveal the effects of scour on the dynamic properties of the bridge.

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