Dynamic Performance of Composite Pavements Under Impact

1997 ◽  
Vol 1570 (1) ◽  
pp. 163-171 ◽  
Author(s):  
Samir N. Shoukry ◽  
D. R. Martinelli ◽  
Olga I. Selezneva
Keyword(s):  
Impact Load ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Deep Understanding ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Asphalt Overlay ◽  
Explicit Finite Element Analysis ◽  
Vertical Displacements ◽  
Pavement Layers

The importance of developing a deep understanding of the behavior of pavement layers under the action of dynamic loads, and the availability of cutting-edge computational and visualization technologies, led to the study presented in this paper. Explicit finite-element analysis was used to investigate the propagation of dynamic displacements induced in pavement layers under the action of an impact load similar to the one applied in a falling weight deflectometer test. The time-dependent dynamic response of a rigid pavement with straight asphalt concrete overlay was studied for two cases of unbonded and fully bonded interfaces between different layers. Significant differences in behavior were observed. Three-dimensional computer graphics and animation of the deformed model were used to display the propagation of vertical dynamic displacements through pavement layers. It was found that in the absence of a perfect bond between all pavement layers, the displacements measured on the top surface correlated little with the deformation measured in subsequent layers. In this case, a complicated pattern of behavior took place between the asphalt overlay and the concrete. The time histories of vertical displacements at selected surface locations and on the top and bottom of every layer were plotted. The plots revealed the existence of time shifts between the maximum displacements experienced by each layer, irrespective of the type of bond assumed between the interfaces.

Optimum cutting depth and spacing of roadheader picks: a numerical simulation using a three-dimensional cracking method

2019 ◽  
Vol 43 (3) ◽  
pp. 366-375
Author(s):  
Weihuang Liu ◽  
Jun Cao ◽  
Tao He ◽  
Gengyuan Gao ◽  
Hulin Li ◽  
...  
Keyword(s):  
Optimum Design ◽  
Three Dimensional ◽  
Mining Operation ◽  
Optimization Method ◽  
Stress Distributions ◽  
Cutting Depth ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Cutting Model

Cutting depth and spacing are two important parameters for the efficiency of a roadheader in mining operation. In this study, the case of a roadheader excavating a coal gallery is taken into account. Based on explicit finite element analysis (FEA), the minimum cutting specific energy (SE) was obtained by a series of numerical simulations. According to the actual cutting process, a three-dimensional (3D) double-pick cutting model was established. The validation for the cutting model showed that it was not only reliable to predict the value of cutting SE, but also capable of accurately simulating the cutting morphology. The variation of cutting moments, stress distributions, and character of coal fragment formation were investigated. The reasons for the different SEs are explained and an optimum design for cutting depth and spacing is given. The results show that SE shrinks by 22.82% using the optimum design compared to the original parameters. Overall, it is believed that the novel 3D double-pick cutting model and the optimization method used in this study are highly appropriate to better understand coal fragmentation and improved mining efficiency.

A Discrete Meshless Lagrangian Based Approach for Soft Impact Damage Modeling in Advanced Propulsion Systems

2010 ◽  
Author(s):  
Aaron Siddens ◽  
Javid Bayandor
Keyword(s):  
Impact Damage ◽  
Three Dimensional ◽  
Jet Engines ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Interactive Behavior ◽  
Explicit Finite Element Analysis ◽  
Highly Nonlinear ◽  
Soft Objects ◽  
Crashworthiness Analysis

Soft impact on aircraft occurs in several forms, such as bird and hail strike. A discrete meshless Lagrangian based approach has been developed for modeling the fluidic behavior of soft objects during impact. This approach shows promise for developing an overall predictive methodology for accurately capturing and assessing dynamic damage in jet engines. This paper focuses on a part of this study aiming to develop a methodology capable of predicting full details of soft impact damage in turbofan engine forward sections. The initial scenario being simulated was a bird strike. Through modeling of the bird in a Lagrangian domain, the method’s suitability for simulating soft impact damage in fan section structures was evaluated. Three-dimensional explicit finite element analysis models were employed to simulate the highly nonlinear and transient response of the interactions between the non-Newtonian bird and the forward engine section resulting from impact and to capture the associated turbofan blade damage, fan assembly vibrations, and subsequent engine casing destruction. Critical features under investigation were the degradation and fracture of the turbofan blades and the engine casing. Results indicated that a meshless soft impactor model was able to produce the fluid-solid interactive behavior expected from a bird. The methodology further succeeded in effectively predicting the intricate subsequent fluid-fan assembly violent interactions. Several important considerations for crashworthiness analysis of forward sections were highlighted.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

NOVEL COUPLING CONSTRAINT TECHNIQUE FOR EXPLICIT FINITE ELEMENT ANALYSIS

2004 ◽  
Vol 01 (02) ◽  
pp. 309-328
Author(s):  
R. J. HO ◽  
S. A. MEGUID ◽  
R. G. SAUVÉ
Keyword(s):  
Finite Element ◽  
Current Method ◽  
Explicit Integration ◽  
Rotation Tensor ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Wide Range ◽  
Large Rotations ◽  
Generalized Constraint

This paper presents a unified novel technique for enforcing nonlinear beam-to-shell, beam-to-solid, and shell-to-solid constraints in explicit finite element formulations. The limitations of classical multi-point constraint approaches are examined at length, particularly in the context of explicit solution schemes. Novel formulation of a generalized constraint method that ensures proper element coupling is then presented, and its computer implementation in explicit integration algorithms is discussed. Crucial in this regard is the accurate and efficient representation of finite rotations, accomplished using an incremental rotation tensor. The results of some illustrative test cases show the accuracy and robustness of the newly developed algorithm for a wide range of deformation, including that in which large rotations are encountered. When compared to existing works, the salient features of the current method are in evidence.

Static and Dynamic Crush Testing and Analysis of a Rail Vehicle Corner Structural Element

1999 ◽  
Author(s):  
Ronald A. Mayville ◽  
Randolph P. Hammond ◽  
Kent N. Johnson
Keyword(s):  
Structural Engineering ◽  
Current Strength ◽  
Test Element ◽  
Structural Element ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Rail Vehicle ◽  
Explicit Finite Element Analysis ◽  
Deformation And Fracture ◽  
Baseline State

Abstract This paper presents the results of an experimental study to establish the strength and energy absorption capability of cab car rail vehicle corner structures built to current strength requirements and for structures modified to carry higher loads and absorb more energy. We reviewed current structures and designed an end beam test element — the most common way of meeting current requirements — whose strength in the baseline state was at least 150,000 lbf. This design was then modified to provide a strength of over 400,000 lbf. The designs, which included consideration of the deformation and fracture response under impact loading, were carried out using conventional structural engineering methods and explicit finite element analysis.

Explicit Finite Element Analysis of Coastal Bridges under Extreme Hurricane Waves

2021 ◽  
Author(s):  
Arsalan Majlesi ◽  
Reza Nasouri ◽  
Adnan Shahriar ◽  
David Amori ◽  
Arturo Montoya ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Coastal Bridges ◽  
Explicit Finite Element Analysis
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