Strength and Stiffness of Aluminum/PTFE Reactive Composites

2001 ◽  
Author(s):  
A. Saigal ◽  
V. S. Joshi
Keyword(s):  
High Strain ◽  
Three Dimensional ◽  
Element Model ◽  
Spherical Particles ◽  
Experimental Measurements ◽  
Aluminum Particles ◽  
Reactive Material ◽  
High Strain Rate Deformation ◽  
Strength And Stiffness ◽  
Shape And Size

Abstract Aluminum/Polytetrafluoroethylene mixtures are currently being studied as reactive material compositions, with focus on shock or impact ignition. In addition, there is an emphasis on increasing the strength of these composites to survive high strain-rate deformation. In this research, an analytical model, based on Eshelby’s approach, and a three-dimensional elastoplastic finite element model were developed along with experimental measurements to investigate the effect of the shape and size of aluminum: spherical particles, whiskers, and fibers, on the strength and stiffness of Aluminum/Polytetrafluoroethylene composites. It was found that the existing surface and size characteristics of aluminum particles (e.g. texturing) play an important role on the mechanical behavior of these composites.

scholarly journals Experimental Study on a New Reinforcement Method for Multilayer Industrial Building’s Vibration

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Kaizhong Xie ◽  
Hongwei Wang ◽  
Jianxi Zhou ◽  
Xiao Luo ◽  
Miao Yue
Keyword(s):  
Natural Frequency ◽  
Three Dimensional ◽  
Element Model ◽  
Industrial Building ◽  
Test Results ◽  
Dimensional Finite Element ◽  
Vibration Experiment ◽  
Length Direction ◽  
Strength And Stiffness ◽  
Three Dimensional Finite Element

In order to study a new reinforcement method for multilayer (4 layers) industrial building’s vibration, firstly, a new reinforcement method using a short-pier shear wall was put forward. Secondly, an engineering example of a multilayer industrial building with abnormal vibration was introduced. A three-dimensional finite element model of multilayer industrial building was established, and field vibration test was carried out. Test results showed that abnormal vibration of industrial building was caused by resonance between machines and multilayer industrial building. Finally, multilayer industrial building was reinforced by a new reinforcement method, and vibration experiment was carried out after reinforcement. The results show that the new reinforcement method has a good reinforcement effect. Strength and stiffness of multilayer industrial building were obviously improved, and natural frequency of industrial building in the length direction increased from 2.45 Hz to 5.87 Hz, natural frequency of industrial building in the width direction increased from 2.94 Hz to 7.83 Hz, frequencies of machines and frequencies of multilayer industrial building were not in resonance range, acceleration and velocity vibration characteristics of multilayer industrial building were improved, which can provide reference for the reinforcement of multilayer industrial building with a similar structural configuration.

A three-dimensional finite element model for locally reinforced timber joints made with hollow dowel fasteners

2000 ◽  
Vol 27 (4) ◽  
pp. 785-797 ◽  
Author(s):  
Z W Guan ◽  
P D Rodd
Keyword(s):  
Finite Element ◽  
Failure Mode ◽  
Three Dimensional ◽  
Ductile Failure ◽  
Element Model ◽  
Premature Failure ◽  
Physical Test ◽  
Timber Joint ◽  
Strength And Stiffness ◽  
Three Dimensional Finite Element

Brittle premature failure caused by splitting parallel to the timber grain is a common failure mode in glulam joints made with solid dowel type fasteners. It is thought that this problem can be alleviated by using hollow steel dowels as the fasteners and reinforcing the timber locally in the area of the joint. In this way, by varying the wall thickness of the dowels and the thickness of the reinforcing members, a chosen combination of strength and stiffness should be attainable together with a ductile failure mode. In this paper, three-dimensional nonlinear finite element models are developed to simulate (i) the structural performance of a timber joint made with a single hollow steel dowel and (ii) a moment transmitting joint made with a number of the dowels, each type being locally reinforced by densified veneer wood. The models incorporate suitably defined elastoplasticity and orthotropic elasticity and also allow for large deformations of the joints as well as for frictional contact between the timber and the dowel. They are calibrated against physical test data from joints loaded to failure.Key words: glulam, densified veneer wood, resin injected, hollow dowel fastener, moment transmitting, ductile failure, finite element.

Finite element analyses on punch shear behaviors of three-dimensional braided composites at microstructure level

2016 ◽  
Vol 26 (7) ◽  
pp. 968-988 ◽  
Author(s):  
Yuanyuan Li ◽  
Wei Zhang ◽  
Rotich K Gideon ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
High Strain ◽  
Three Dimensional ◽  
Rate Sensitivity ◽  
Element Model ◽  
Shear Loading ◽  
Composite Panel ◽  
Braided Composites ◽  
Braided Composite

The punch shear properties of three-dimensional carbon/epoxy braided composites were studied at quasi-static and high strain rates with finite element method at microstructure level. A microstructure model was developed to analyze the stress distribution and progressive damage of the braided composite panel with different thickness. The braiding yarns were considered as an elastic and transversely isotropic material. Ductile and shear criterion were used in finite element model to obtain the damage evolution. It was found that the braided composite exhibited high strain rate sensitivity under punch shear loading. The thickness influences the punch shear strength significantly. The braiding yarns at surface and corner parts have tensile and pullout failure modes, while at inner part have shear damage mode.

scholarly journals Dynamic Behavior of Advanced Ti Alloy under Impact Loading: Experimental and Numerical Analysis

2011 ◽  
Vol 70 ◽  
pp. 207-212
Author(s):  
Murat Demiral ◽  
Anish Roy ◽  
Vadim V. Silberschmidt
Keyword(s):  
Numerical Analysis ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Three Dimensional ◽  
Element Model ◽  
Industrial Applications ◽  
Material Behavior ◽  
Hopkinson Pressure Bar ◽  
Strain And Strain Rate

Industrial applications of Ti-based alloys, especially in aerospace, marine and offshore industries, have grown significantly over the years primarily due to their high strength, light weight as well as good fatigue and corrosion-resistance properties. A combination of experimental and numerical studies is necessary to predict a material behavior of such alloys under high strain-rate conditions characterized also by a high level of strains accompanied by high temperatures. A Split Hopkinson Pressure Bar (SHPB) technique is a commonly used experimental method to characterize a dynamic stress-strain response of materials at high strain rates. In a SHPB test, the striker bar is shot against the free end of the incident stress bar, which on impact generates a stress pulse propagating in the incident bar towards the specimen sandwiched between the incident and transmitted bars. An experimental study and a numerical analysis based on a three-dimensional finite element model of the SHPB experiment are performed in this study to assess various features of the underlying mechanics of deformation processes of the alloy tested at high-strain and -strain-rate regimes.

The Study on Multi-Factor Coupling Numerical Simulation for Vehicle Cover Panel Stamping Forming

2010 ◽  
Vol 156-157 ◽  
pp. 320-325
Author(s):  
Xiao Gang Qiu ◽  
Huai An Yi
Keyword(s):  
Material Parameter ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Great Influence ◽  
Element Model ◽  
Geometric Parameters ◽  
Three Dimensional Model ◽  
Blank Holder ◽  
Blank Size ◽  
Shape And Size

This article uses UG to establish the three-dimensional model for the automobile cover panel parts, and establish a parts technological addendum surface and binder surface. This model has been converted to DYNAFORM, in which the parts finite element model is established. It also uses DYNAFORM software to carry out simulation analysis and orthogonal analysis of the geometric parameters of rib, obtaining the influence rule of the drawbead geometric parameters to drawbead resistance. It has studied the influence of many factors on the parts forming such as blank size, blank holder force(BHF), the material parameter and so on. The result shows that during the process of stamping, the shape and size of blank has played an important role in the sheet flowing; BHF has a great influence upon the wrinkling and cracking of the parts; material parameter, the value of r, mainly affects the drawing deformation while the value of n produces a great impact on the plane strain, bulging deformation. Through optimizing the shape and size of the blank and BHF, it obtains the best material properties parameters to satisfy the parts smooth forming that is: 0.25, 2.15. After the scene stamping production, it confirms the practicality of the optimization solutions.

Finite Element Simulation of Tire-Rim Interface

1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Simulation ◽  
Contact Pressure ◽  
Element Model ◽  
Experimental Measurements ◽  
Inflation Pressure ◽  
Interference Fit ◽  
Element Simulation ◽  
Rubber Composite

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

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