Finite element prediction of the impact compressive properties of three-dimensional braided composites using multi-scale model

2015 ◽  
Vol 128 ◽  
pp. 381-394 ◽  
Author(s):  
Yumin Wan ◽  
Youjiang Wang ◽  
Bohong Gu
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Scale Model ◽  
Compressive Properties ◽  
Braided Composites ◽  
Multi Scale ◽  
The Impact ◽  
Finite Element Prediction

Nonlinear Finite Element Analysis of Non-Structural Components Anchorage under Extreme Wind Loads

2019 ◽  
Author(s):  
Sálvio A. ALMEIDA Jr ◽  
Serhan Guner
Keyword(s):  
Finite Element ◽  
Elevated Temperatures ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Nonlinear Finite Element ◽  
Scale Model ◽  
Structural Components ◽  
Element Analysis ◽  
Multi Scale ◽  
Service Load

<p>Steel anchors are widely used to fasten structures and non-structural components (NSC) to rooftop concrete slabs, especially in high-rise buildings. However, several NSC anchorage failures have been observed in the last decades upon the incidence of hurricanes, resulting in loss of service in essential buildings, detachment of the component, and water intrusion, all of which significantly delayed the recovery of the affected communities. From the observed failures, three main mechanisms were identified: steel rupture, concrete breakout, and bond failure. In this study, a three-dimensional nonlinear finite element methodology using a concrete damaged plasticity approach is developed to predict the response of steel anchors installed into a concrete slab. The methodology is verified with experimental results for each failure mechanism and subsequently used to study the effect of service-load concrete cracking and elevated temperatures – common conditions at rooftop level – on the response of the anchors. In addition, a first-of-its-kind multi-scale model of an NSC and its anchorage is created using the proposed methodology to investigate its behavior under dynamic hurricane load application. The findings suggest that these conditions can compromise the performance of NSC or promote its failure.</p>

Numerical analysis of punch shear failure and stress characteristics of three-dimensional braided composite with different braiding angles

2019 ◽  
Vol 28 (9) ◽  
pp. 1418-1437
Author(s):  
Yuanyuan Li ◽  
Zhijuan Pan ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Shear Failure ◽  
Shear Bands ◽  
Three Dimensional ◽  
Element Model ◽  
Scale Model ◽  
Strain Rates ◽  
Braided Composites ◽  
Braided Composite ◽  
Multi Scale ◽  
Braided Structure

This paper presents a multi-scale finite element model to calculate the stress field and analyze the punch shear failure of three-dimensional braided composite at high strain rates. The multi-scale model was established based on real braided structure taking the surface and corner braiding yarns into consideration. Constitutive material modeling and failure criterions were introduced into the model. Three braiding angles of 25°, 35°, and 45° were applied to reveal the relations between failure states and braided structure. The results showed that the punch shear failure states and stress distribution were greatly dependent on the strain rates and braiding angles. Nonuniform stress propagation resulted in shear bands and different formation paths were observed on the composite with different braiding angles. The ultimate failure of braided composite was determined by comprehensive action of compressive and tensile stress. In addition, the progressive damage of typical braiding yarns in different conditions was obtained from the modeling simulation. The three-dimensional braided composites with different braiding angles showed unique failure morphology. It was closely determined by the complex braided structures.

Three-dimensional Reconstruction of Microscopic Image Based on Multi-ST Algorithm

2020 ◽  
Vol 64 (2) ◽  
pp. 20506-1-20506-7
Author(s):  
Min Zhu ◽  
Rongfu Zhang ◽  
Pei Ma ◽  
Xuedian Zhang ◽  
Qi Guo
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Scale Model ◽  
Microscopic Image ◽  
Multi Scale ◽  
Gaussian Pyramid ◽  
Cost Aggregation ◽  
Dimensional Reconstruction ◽  
Image Pairs ◽  
Accurate Matching

Abstract Three-dimensional (3D) reconstruction is extensively used in microscopic applications. Reducing excessive error points and achieving accurate matching of weak texture regions have been the classical challenges for 3D microscopic vision. A Multi-ST algorithm was proposed to improve matching accuracy. The process is performed in two main stages: scaled microscopic images and regularized cost aggregation. First, microscopic image pairs with different scales were extracted according to the Gaussian pyramid criterion. Second, a novel cost aggregation approach based on the regularized multi-scale model was implemented into all scales to obtain the final cost. To evaluate the performances of the proposed Multi-ST algorithm and compare different algorithms, seven groups of images from the Middlebury dataset and four groups of experimental images obtained by a binocular microscopic system were analyzed. Disparity maps and reconstruction maps generated by the proposed approach contained more information and fewer outliers or artifacts. Furthermore, 3D reconstruction of the plug gauges using the Multi-ST algorithm showed that the error was less than 0.025 mm.

Spreadsheet Tool for Quick-Turn 3D Numerical Modeling of Package Thermal Performance With Non-Uniform Die Heating

2001 ◽  
Author(s):  
Abhay A. Watwe ◽  
Ravi S. Prasher
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Finite Volume ◽  
Thermal Performance ◽  
Three Dimensional ◽  
3D Numerical Modeling ◽  
Conventional Analysis ◽  
Time Required ◽  
The Impact ◽  
Fourier Equation

Abstract Traditional methods of estimating package thermal performance employ numerical modeling using commercially available finite-volume or finite-element tools. Use of these tools requires training and experience in thermal modeling. This methodology restricts the ability of die designers to quickly evaluate the thermal impact of their die architecture due to the added throughput time required to enlist the services of a thermal analyst. This paper describes the development of an easy to use spreadsheet tool, which performs quick-turn numerical evaluations of the impact of non-uniform die heating. The tool employs well-established finite-volume numerical techniques to solve the steady-state, three-dimensional Fourier equation of conduction in the package geometry. Minimal input data is required and the inputs are customized using visual basic pull-down menus to assist die designers who may not be thermal experts. Data showing comparison of the estimates from the spreadsheet tool with that obtained from a conventional analysis using the commercially available finite element code ANSYS™ is also presented.

Effective Shear Area in One Dimensional Ship Hull Finite Element Models to Predict Natural Frequencies of Vibration

2013 ◽  
Author(s):  
Osvaldo Pinheiro de Souza e Silva ◽  
Severino Fonseca da Silva Neto ◽  
Ilson Paranhos Pasqualino ◽  
Antonio Carlos Ramos Troyman
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Numerical Results ◽  
Computational Method ◽  
Scale Model ◽  
Dimensional Model ◽  
One Dimensional ◽  
Shear Area

This work discusses procedures used to determine effective shear area of ship sections. Five types of ships have been studied. Initially, the vertical natural frequencies of an acrylic scale model 3m in length in a laboratory at university are obtained from experimental tests and from a three dimensional numerical model, and are compared to those calculated from a one dimensional model which the effective shear area was calculated by a practical computational method based on thin-walled section Shear Flow Theory. The second studied ship was a ship employed in midshipmen training. Two models were made to complement some studies and vibration measurements made for those ships in the end of 1980 decade when some vibration problems in them were solved as a result of that effort. Comparisons were made between natural frequencies obtained experimentally, numerically from a three dimensional finite element model and from a one dimensional model in which effective shear area is considered. The third and fourth were, respectively, a tanker ship and an AHTS (Anchor Handling Tug Supply) boat, both with comparison between three and one dimensional models results out of water. Experimental tests had been performed in these two ships and their results were used in other comparison made after the inclusion of another important effect that acts simultaneously: the added mass. Finally, natural frequencies experimental and numerical results of a barge are presented. The natural frequencies numerical results of vertical hull vibration obtained from these approximations of effective shear areas for the five ships are finally discussed.

scholarly journals 3D Finite Element Model Simulating the Behaviour of Filling Soils Used to Set Up a New Placement Method for Separate Sewer Systems

2019 ◽  
Vol 8 (3) ◽  
pp. 87-98
Author(s):  
Alaa Abbas ◽  
Felicite Ruddock ◽  
Rafid Alkhaddar ◽  
Glynn Rothwell ◽  
Iacopo Carnacina ◽  
...  
Keyword(s):  
Finite Element ◽  
Soil Properties ◽  
Model Simulation ◽  
New Method ◽  
Traffic Load ◽  
Scale Model ◽  
Fe Model ◽  
Fe Method ◽  
Buried Pipes ◽  
The Impact

The use of a finite element (FE) method and selection of the appropriate model to simulate soil elastoplastic behaviour has confirmed the importance and sensitivity of the soil properties on the accuracy when compared with experimental data. The properties of the filling soil play a significant role in determining levels of deformation and displacement of both the soil and subterranean structures when using the FE model simulation. This paper investigates the impact of the traffic load on the filling soil deformation when using the traditional method, one pipe in a trench, and a new method, two pipes in a single trench one over the other, for setting up a separate sewer system. The interaction between the buried pipes and the filling soils has been simulated using an elastoplastic FE model. A modified Drucker–Prager cap constitutive model was used to simulate the stress-strain behaviours of the soil. A series of laboratory tests were conducted to identify the elastoplastic properties of the composite soil used to bury the pipes. The FE models were calibrated using a physical lab model for testing the buried pipes under applied load. This allows the FE model to be confidently upgraded to a full-scale model. The pipe-soil interactions were found to be significantly influenced by the soil properties, the method of placing the pipes in the trench and the diameters of the buried pipes. The deformation of the surface soil was decreased by approximately 10% when using the new method of setting up the separate sewer.

scholarly journals Thin Solid Film Electrolyte and Its Impact on Electrode Polarization in Solid Oxide Fuel Cells Studied by Three-Dimensional Microstructure-Scale Numerical Simulation

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5127
Author(s):  
Tomasz A. Prokop ◽  
Grzegorz Brus ◽  
Shinji Kimijima ◽  
Janusz S. Szmyd
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Reaction Rates ◽  
Solid Oxide ◽  
Scale Model ◽  
Electrode Polarization ◽  
Computational Domain ◽  
Oxide Fuel ◽  
The Impact

In this work, a three-dimensional microstructure-scale model of a Solid Oxide Fuel Cell’s Positive-Electrolyte-Negative assembly is applied for the purpose of investigating the impact of decreasing the electrolyte thickness on the magnitude, and the composition of electrochemical losses generated within the cell. Focused-Ion-Beam Scanning Electron Microscopy reconstructions are used to construct a computational domain, in which charge transport equations are solved. Butler–Volmer model is used to compute local reaction rates, and empirical relationships are used to obtain local conductivities. The results point towards three-dimensional nature of transport phenomena in thin electrolytes, and electrode-electrolyte interfaces.

scholarly journals New Design Procedure of Transtibial ProsthesisBed Stump Using Topological Optimization Method

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1837 ◽  
Author(s):  
Martin Sotola ◽  
David Stareczek ◽  
David Rybansky ◽  
Jiri Prokop ◽  
Pavel Marsalek
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Design Procedure ◽  
Optimization Method ◽  
Topological Optimization ◽  
Element Analysis ◽  
Current Application ◽  
Transtibial Prosthesis ◽  
Walking Biomechanics ◽  
The Impact

This paper presents a new design procedure for production of a transtibial prosthesis bed stump by three-dimensional (3D) printing with topological optimization. The suggested procedure combines the medical perspective with finite element analysis and facilitates regaining the symmetry in patients with transtibial prosthesis, which leads to life improvement. The particular focus of the study is the weight reduction of the lower part of the bed stump, while taking into account its stiffness and load-bearing capacity. The first part of the work deals with the analysis of the subject geometry of the bed stump, which is usually oversized in terms of the weight and stiffness that are necessary for the current application. In the second part, an analysis of walking biomechanics with a focus on the impact and rebound phases is presented. Based on the obtained information, a spatial model of the lower part of the bed stump is proposed in the third phase, in which the finite element method is described. In the fourth part, the topological optimization method is used for reducing the structure weight. In the last part, the results of the designed model are analyzed. Finally, the recommendations for the settings of the method are presented. The work is based on the practical industry requirements, and the obtained results will be reflected in the design of new types of transtibial prosthesis.

Finite-element analysis of multi-body contacts for pile driving using a hydraulic pile hammer

2011 ◽  
Vol 225 (5) ◽  
pp. 1153-1161 ◽  
Author(s):  
Y Guo ◽  
J P Hu ◽  
L Y Zhang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Test Point ◽  
Pile Driving ◽  
Penalty Function Method ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Material Choice ◽  
Multi Body ◽  
The Impact

This article treats the pile driving as multi-body dynamic contacts. By using the penalty function method and three-dimensional model of finite-element method, the dynamic process of pile driving is acquired and a method for choosing the cushion material of the hydraulic pile hammer to improve driving efficiency is proposed. The process of pile driving in the real situation of an industrial experiment is simulated. The results of stress on test point are consistent with the test point. By analysing the stress distributed along the direction of pile radius and pile axis, the rule of the stress distribution on the pile is concluded. The rule for cushion material choice is obtained by comparing the influence for the impact stress with different elastic modulus ratio of the hammer cushion to the pile and the pile cushion to the pile.

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