Optical Microscopy-Aided Indentation Tests

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
D. A. Doman ◽  
R. Bauer ◽  
A. Warkentin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Optical Microscopy ◽  
High Speed ◽  
Material Model ◽  
Element Model ◽  
Rolling Contact ◽  
Analytical Models ◽  
Indentation Tests ◽  
The Finite Element Model

The contact characteristics of ceramic-metallic interactions are of critical importance in the design of high-speed ceramic rolling contact bearings. This type of interaction is not described well by traditional indentation tests since small displacements and barely discernable indentations are encountered. In this work, an optical microscopy system is described that is used to measure small indenter displacements accurately. Images of the indenter are taken throughout the test and processed using sophisticated edge detection algorithms to accurately determine the position of the center of the indenter. Thus, the indenter displacements on the order of 1μm can be measured independent of any structural flexibility present in the test apparatus. Experimental indentation tests using an alumina indenter mounted on a stainless steel post were performed and processed with the optical system. The results were compared to existing analytical models for fully elastic and elastoplastic cases as well as a finite element model developed using a Johnson–Cook plasticity material model. The comparison shows that the analytical models do not predict the experimental results well, whereas the finite element model agrees very well. Subsequent analysis of the finite element model shows that the size of the contact zone and pressure distributions, both very important in the design of bearings, can be more accurately described than the traditional analytical treatments.

Modal Analysis of BT Spindle-Toolholder Interface Based on Abaqus/Standard

2013 ◽  
Vol 662 ◽  
pp. 632-636
Author(s):  
Yong Sheng Zhao ◽  
Jing Yang ◽  
Xiao Lei Song ◽  
Zi Jun Qi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Modal Analysis ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Element Model ◽  
Contact Theory ◽  
High Speed Machining ◽  
The Finite Element Model

The quality of high speed machining is directly related to dynamic characteristics of spindle-toolholder interface. The paper established normal and tangential interactions of BT spindle-toolholder interface based on finite element contact theory, and analysed free modal in Abaqus/Standard. Then the result was compared with the experimental modal analysis. It shows that the finite element model is effective and could be applied in the future dynamic study of high-speed spindle system.

scholarly journals Experiment and Analysis of Cord Stress on High-Speed Radial Tire Standing Waves

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Peng-Fei Sun ◽  
Hong-Wu Huang ◽  
Shui-Ting Zhou ◽  
Yi-Jui Chiu ◽  
Meng Du ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Standing Waves ◽  
Element Model ◽  
Experimental Results ◽  
Radial Tire ◽  
Oblique Wave ◽  
Vehicle Velocity ◽  
The Finite Element Model

This paper elaborates on the production mechanisms of standing waves during high-speed tire rolling and analyzes the relationship between the change of wavelength of sidewall waves and the vehicle velocity, from an oblique wave point of view. A finite element model for a 195/65R15 radial tire is established with the nonlinear analysis software ABAQUS, based on the tire structure and cord parameters. This paper comparatively analyzes the finite element simulation results and experimental results of the tire load-sinkage relation and the load vs inflatable section width relation and finds little difference between the simulation and experimental results. A similar analysis studies the change in the wavelength of sidewall standing waves at different vehicle velocities during high-speed tire rolling. The calculated value by the oblique wave approach, the value by simulation, and the experimental results demonstrate high consistency, concluding that during high-speed tire rolling, the wavelength of sidewall standing waves increases with vehicle velocity. Thus, the accuracy of the finite element model is verified under both static and dynamic conditions. Under a constant tire pressure and load, the impact of velocity change on tire-cord stress during high-speed tire rolling is studied based on the finite element model so as to identity the relation between the cord stress and standing waves.

A Hybrid 2.5D High Speed Strip Theory Method and its Application to Apply Pressure Loads to 3D Full Ship Finite Element Models

2014 ◽  
Author(s):  
Chengbi Zhao ◽  
Ming Ma
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Hybrid Approach ◽  
Structural Models ◽  
Element Model ◽  
3D Finite Element ◽  
Hull Girder ◽  
Strip Theory ◽  
The Finite Element Model

As the three-dimensional finite element model has become the de facto standard for ship structural design, interest in accurately transferring seakeeping loads to panel based structural models has increased dramatically in recent years. In today’s design practices, panel based hydrodynamic analyses are often used for mapping seakeeping loads to 3D FEM structural models. However, 3D panel based hydrodynamic analyses are computationally expensive. For monohull ships, methods based on strip theories have been successfully used in the industry for many years. They are computationally efficient, and provide good predictions for motions and hull girder loads. However, many strip theory methods provide only hull girder sectional forces and moments, such as vertical bending moment and vertical shear force, which are difficult to apply to 3D finite element structural models. Previously, the authors have proposed a hybrid strip theory method to transfer 2D strip theory based seakeeping loads to 3D finite element models. In the hybrid approach, the velocity potentials of strip sections are first calculated based on the ordinary 2D strip theories. The velocity potentials of a finite element panel are obtained from the interpolation of the velocity potentials of the strip sections. The panel pressures are then computed based on Bernoulli’s equation. Integration of the pressure over the finite element model wetted panels yields the hydrodynamic forces and moments. The equations of motion are then formulated based on the finite element model. The method not only produces excellent ship motion results, but also results in a perfectly balanced structural model. In this paper, the hybrid approach is extended to the 2.5D high speed strip theory. The simple Rankine source function is used to compute velocity potentials. The original linearized free surface condition, where the forward speed term is not ignored, is used to formulate boundary integral equations. A model based on the Series-64 hull form was used for validating the proposed hybrid method. The motion RAOs are in good agreement with VERES’s 2.5D strip theory and with experimental results. Finally, an example is provided for transferring seakeeping loads obtained by the 2.5D hybrid strip theory to a 3D finite element model.

Research on Finite Element Model of Wheel-Rail Contact

2014 ◽  
Vol 644-650 ◽  
pp. 7-10
Author(s):  
Hai Zhang ◽  
Xiao Yi Hu ◽  
Feng Tao Lin ◽  
Xin Jian Zhou
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Normal Force ◽  
Element Model ◽  
Rolling Contact ◽  
Contact Theory ◽  
Maximum Pressure ◽  
The Finite Element Method ◽  
Creep Force ◽  
The Finite Element Model

Many researchers applied creepage to calculating creep force, but relation between creepage and creep force are very complex and it has been a major problem for solving rolling contact theory. The paper uses the finite element method for studying directly creep forces and apply it to the studies of wheel-rail rolling contact. Paper establishes the finite element model of wheel-rail rolling contact based on ALE method in ABAQUS, and simulated unsteady state of wheel-rail rolling contact and research normal force of wheel-rail contact pitch. Results show that the normal maximum pressure in left wheel have a trend toward the center of contact pitch and the normal maximum pressure in right wheel have a trend toward the other center of contact pitch with increasement of displacement

Assessment of Shoulder and Chest Protection of Wearable Motorcycle Airbags

2019 ◽  
Author(s):  
Davide Girardi ◽  
Edoardo Marconi ◽  
Matteo Massaro
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Test ◽  
Material Model ◽  
Element Model ◽  
Inflation Pressure ◽  
Human Body Model ◽  
Physics Simulation ◽  
Set Up ◽  
The Finite Element Model

Abstract The application of numerical simulation to wearable airbags for motorcyclists is relatively recent and only few works about this topic can be found in the literature. This research uses multi-physics simulation to analyse a new wearable airbag geometry, primarily designed to protect the shoulders of motorcycle riders, with the aim of assessing the effect of inflation pressure on the protection performance. The finite element model of the airbag employs a simple linear-isotropic material model, calibrated though the comparison between experimental and numerical outcomes of a drop test, together with the analysis of the airbag inflated geometry. The finite element model of the wearable device is then fitted to a dummy model and a human body model, in order to be used in a parametric analysis. Two set-ups are considered. The first is a thorax impact test, used to assess the effect of inflation pressure on chest protection. A modification to the bag geometry is also proposed and tested on this configuration. The second set-up is a shoulder impact test, used to assess the effect of inflation pressure on shoulder protection. In both tests an optimal inflation pressure can be found, but the maximization of shoulder protection proved more critical and should therefore drive the choice of this parameter.

Modeling Mismatch Strain Induced Self-Folding of Bilayer Gel Structures

2016 ◽  
Vol 08 (07) ◽  
pp. 1640004 ◽  
Author(s):  
Rui Xiao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Explicit Expression ◽  
Analytical Model ◽  
Analytical Solutions ◽  
Element Model ◽  
Analytical Models ◽  
Swelling Ratio ◽  
Mismatch Strain ◽  
The Finite Element Model

When exposed to a solvent, a gel bilayer beam can bend due to different swelling abilities of the two layers. In this work, an analytical model is derived to obtain the curvature of the bilayer beam. The model is further linearized to obtain an explicit expression for the curvature. The finite element model is used to verify the above analytical solutions. The results show the curvature predicted by the analytical model is in excellent agreement with the finite element results. The linear model predicts a smaller curvature at large swelling ratio. These results suggest the analytical models can provide a design metric for self-folding 3D structures.

scholarly journals Damage Identification of High-speed Maglev Guideway Girder Based on Modal Identification

2021 ◽  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Health Monitoring ◽  
High Speed ◽  
Damage Identification ◽  
Element Model ◽  
High Tech ◽  
Maglev Train ◽  
Identification Method ◽  
The Finite Element Model

Abstract. As a modern high-tech rail vehicle, the maglev train realizes the non-contact suspension and guidance between the train and the guideway, which greatly reduces the resistance of the system. Due to the high-speed operation characteristics of maglev trains, the structural health monitoring of guideway girders is particularly important for the safety and stability of maglev train operation. This paper takes the maglev train guideway girder as the monitoring target, and the finite element model of the maglev vehicle-guideway is established to simulate the running state of the train passing through the guideway girder. The dynamic response data of the guideway girder is obtained in the finite element model, considering healthy states and different damage states of the guideway girder. Then, a modal-based damage identification method is proposed, which obtains the guideway girder damage sensitive characteristics by decomposing the guideway girder acceleration response signal. Finally, based on the measured guideway girder acceleration data, this paper verifies the effectiveness of the damage identification method in guideway girder structure health monitoring, which provides reference and guidance for the future maintenance of the maglev guideway girder.

Non-Linear FEA of AA 5083 Welded Joints for High-Speed Marine Vehicles

2020 ◽  
Author(s):  
Pasqualino Corigliano ◽  
Vincenzo Crupi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Welded Joints ◽  
High Speed ◽  
Element Model ◽  
Plastic Behavior ◽  
Full Field ◽  
Marine Vehicles ◽  
Non Linear ◽  
The Finite Element Model

The AA 5083 aluminium alloy is widely used in high speed marine vehicles. The aim of this scientific work was to develop and validate a procedure, starting only from hardness measurements, to predict the elastic-plastic behavior of AA 5083 welded joints under static loading using non-linear FEA analyses. The hardness measurements allowed identifying the different zones and to assess their different mechanical properties, which were considered in the finite element model. Finally, the finite element model results were validated experimentally, comparing the results with the measurements obtained by means of a full-field technique such as the Digital Image Correlation technique.

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