scholarly journals Study of the Mechanical Properties of Wood under Transverse Compression Using Monto Carlo Simulation-Based Stochastic FE Analysis

Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 32
Author(s):  
Guofang Wu ◽  
Yinlan Shen ◽  
Feng Fu ◽  
Juan Guo ◽  
Haiqing Ren
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Statistical Characteristic ◽  
Mechanical Performance ◽  
Tangential Direction ◽  
Fe Analysis ◽  
Transverse Compression ◽  
Interesting Approach ◽  
Almost All

Wood is an anisotropic material, the mechanical properties of which are strongly influenced by its microstructure. In wood, grain compression strength and modulus are the weakest perpendicular to the grain compared to other grain directions. FE (finite element) models have been developed to investigate the mechanical properties of wood under transverse compression. However, almost all existing models were deterministic. Thus, the variations of geometry of the cellular structure were not considered, and the statistical characteristic of the mechanical property was not involved. This study aimed to develop an approach to investigate the compression property of wood in a statistical sense by considering the irregular geometry of wood cells. First, the mechanical properties of wood under radial perpendicular to grain compression was experimentally investigated, then the statistical characteristic of cell geometry was extracted from test data. Finally, the mechanical property of wood was investigated using the finite element method in combination with the Monte Carlo Simulation (MCS) techniques using randomly generated FE models. By parameter sensitivity analysis, it was found that the occurrence of the yield points was caused by the bending or buckling of the earlywood axial tracheid cell wall in the tangential direction. The MCS-based stochastic FE analysis was revealed as an interesting approach for assessing the micro-mechanical performance of wood and in assisting in understanding the mechanical behavior of wood based on its hierarchical structure.

scholarly journals Mechanical Performance Evaluation of the Al-Mg-Si-(Cu) Aluminum Alloys after Transient Thermal Shock through an Novel Equivalent Structure Design and Finite Element Modeling

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 537
Author(s):  
Congchang Xu ◽  
Ke Liu ◽  
Hong He ◽  
Hanlin Xiang ◽  
Xinxin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Thermal Shock ◽  
Constitutive Relation ◽  
Mechanical Performance ◽  
Lap Joints ◽  
Structure Design ◽  
Equivalent Structure ◽  
Material Constitutive Relation ◽  
Transient Thermal

In this paper, the microstructure evolution and mechanical performance of the Al-Mg-Si-(Cu) aluminum alloy after transient thermal shock were investigated through experimental tests and finite element simulations. A novel equivalent structure was designed as a typical case in which one side of the plate was welded therefore the other side was thermally shocked with different temperature distribution and duration. The temperature gradient which influences most importantly the mechanical properties was simulated and experimentally verified. Through cutting layers and tensile testing, the mechanical response and material constitutive relation were obtained for each layer. Gurson-Tvergaard-Needlemen (GTN) damage parameters of these samples under large strains were then obtained by the Swift law inverse analysis approach. By sorting the whole welded joint into multi-material composed structure and introducing the obtained material constitutive relation and damage parameters, tensile properties were precisely predicted for typical types of weld joint such as butt, corner, and lap joints. The results show that precipitate coarsening, phase transformation from β″ phase to Q′ phase, and dissolving in the temperature range of 243.3–466.3 °C during the thermal shock induced a serious deterioration of the mechanical properties. The highest reduction of the ultimate tensile strength (UTS) and yield strength (YS) would be 38.6% and 57.4% respectively. By comparing the simulated and experimentally obtained force-displacement curves, the error for the above prediction method was evaluated to be less than 8.1%, indicating the proposed method being effective and reliable.

Computational mechanical property determination of viscoelastic/plastic materials from nanoindentation creep test data

2009 ◽  
Vol 24 (3) ◽  
pp. 1245-1257 ◽  
Author(s):  
Jianjun Wang ◽  
Timothy C. Ovaert
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Test Data ◽  
Plastic Material ◽  
Test Method ◽  
Element Formulation ◽  
Unknown Parameters ◽  
Plastic Materials

Nanoindentation is a widely accepted test method for materials characterization. On account of the complexity of contact deformation behavior, design of parametric constitutive models and determination of the unknown parameters is challenging. To address the need for identification of mechanical properties of viscoelastic/plastic materials from nanoindentation data, a combined numerical finite element/optimization-based indentation modeling tool was developed, fully self-contained, and capable of running on a PC as a stand-alone executable program. The approach uses inverse engineering and formulates the material characterization task as an optimization problem. The model development consists of finite element formulation, viscoelastic/plastic material models, heuristic estimation to obtain initial solution boundaries, and a gradient-based optimization algorithm for fast convergence to extract mechanical properties from the test data. A four-parameter viscoelastic/plastic model is presented, then a simplified three-parameter model with more rapid convergence. The end result is a versatile tool for indentation simulation and mechanical property analysis.

Analysis of the Mechanical Property of Collapse in Shallow-Buried Loess Tunnel under Unsymmetrical Pressure

2013 ◽  
Vol 645 ◽  
pp. 426-429 ◽  
Author(s):  
Xiao Hui Xue ◽  
Zhong Ming Su
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Mechanical Property ◽  
Finite Element ◽  
Collapse Mechanism ◽  
Tunnel Excavation ◽  
Finite Element Numerical Simulation ◽  
Tunnel Collapse ◽  
Primary Support

Based on selecting a tunnel collapse under typical conditions of the shallow-buried terrain under unsymmetrical pressure, analyzing the monitoring measurement date, using the software of finite element numerical simulation, the paper simulates the tunnel excavation in lengthwise, deduces the change laws of stress in primary support, the mechanical properties and the collapse mechanism.

Finite element analysis of a personalized femoral scaffold with designed microarchitecture

2009 ◽  
Vol 224 (7) ◽  
pp. 877-889 ◽  
Author(s):  
P Pandithevan ◽  
G Saravana Kumar
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Computer Aided Design ◽  
Strain State ◽  
Mechanical Performance ◽  
Physiological Stress ◽  
Tissue Growth ◽  
Bone Tissue Regeneration ◽  
Load Bearing ◽  
Ct Data

Tissue engineering scaffolds with intricate and controlled internal structure can be realized using computer-aided design (CAD) and layer manufacturing (LM) techniques. Design and manufacturing of scaffolds for load-bearing bone sites should consider appropriate biocompatibile materials with interconnected porosity, surface properties, and sufficient mechanical properties that match the surrounding bone, in order to provide adequate support, and to mimic the physiological stress—strain state so as to stimulate new tissue growth. The authors have previously published methods for estimating subject- and site-specific bone modulus using computed tomography (CT) data, CAD, and process planning for LM of controlled porous scaffolds. This study evaluates the mechanical performance of the designed porous hydroxyapite scaffolds in load-bearing sites using a finite element (FE) approach. A subject-specific FE analysis using femoral, defect site geometry and anisotropic material assignment based on CT data is employed. Mechanical behaviour of the femur with scaffold in stance-phase gait loading, which has been shown experimentally to produce clinically relevant results, is analysed. The comparison of results with simulation of healthy femur shows an overall correspondence in stress and strain state which will provide optimized mechanical properties for avoiding stress shielding, and adequate strength to avoid failure risk and for active bone tissue regeneration.

Experimental Determination of Mechanical Properties for the Purposes of Numerical Simulations of Car Bumper Tests

2015 ◽  
Vol 732 ◽  
pp. 59-62
Author(s):  
Petr Horník
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Numerical Simulations ◽  
Experimental Determination ◽  
Input Data ◽  
Fe Analysis ◽  
Experimental Methodology ◽  
Material Input

Finite-element (FE) analysis is important instrument for prediction of plastic car bumper tests. Accuracy of FE analysis depends on accuracy of material input data. It has developed experimental methodology for identification of mechanical properties. The methodology leads to more accurate material input data for numerical simulations.

The role of crystalline anisotropy in mechanical property extractions through Berkovich indentation

2009 ◽  
Vol 24 (3) ◽  
pp. 1235-1244 ◽  
Author(s):  
J. Alcalá ◽  
D. Esqué-de los Ojos ◽  
S.A. Rodríguez
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Face Centered Cubic ◽  
Instrumented Indentation ◽  
Crystal Plasticity Finite Element ◽  
Conventional Procedure ◽  
Crystalline Anisotropy ◽  
Face Centered

This work uses crystal plasticity finite element simulations to elucidate the role of elastoplastic anisotropy in instrumented indentation P–hs curve measurements in face-centered cubic (fcc) crystals. It is shown that although the experimental fluctuations in the loading stage of the P–hs curves can be attributed to anisotropy, the variability in the unloading stage of the experiments is much greater than that resulting from anisotropy alone. Moreover, it is found that the conventional procedure used to evaluate the contact variables ruling the unloading P–hs curve introduces an uncertainty that approximates to the more fundamental influence of anisotropy. In view of these results, a robust procedure is proposed that uses contact area measurements in addition to the P–hs curves to extract homogenized J2-plasticity-equivalent mechanical properties from single crystals.

The Effects of Operational, Testing and Material Characterisations On the Change in Yield Strength From Plate to Pipe

2021 ◽  
Author(s):  
Jingsi Jiao ◽  
Cheng Lu ◽  
Valerie Linton ◽  
Frank Barbaro
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Yield Strength ◽  
Finite Element Model ◽  
Mechanical Performance ◽  
Element Model ◽  
Critical Knowledge ◽  
Operational Testing ◽  
Wide Range ◽  
The Individual

Abstract The mechanical performance of the pipe sample has a direct influence on their application in real environments and a significant economic impact on manufacturers, especially when the pipe products do not meet required specifications. There is often a change in the yield strength from plate to pipe due to strain hardening and the Bauschinger effect. The current work sets out to provide a critical knowledge base for this change, with emphasizing the important influence of the plate mechanical properties on the pipe. So that the quality of pipe can be further ensured. In the work, firstly, the historical data of the pipe yield strength were collected and plotted together from a wide range of published sources to provide a broad quantitative insight, which provides a quantitative review on the parameters that govern the final pipe yield strength. Secondly, a Finite Element model of the pipe forming and mechanical evaluation was developed and then validated with available industrial testing results, in where the effects of operational and testing parameters on the pipe yield strength were analysed and discussed in detail. Finally, using the validated Finite Element model, a parametric study was conducted to dissect the individual role that each of the material parameters plays on changing the yield strength from plate to pipe. We found that the yield strength of the pipe can differ significantly. This work sheds lights on the desired plate mechanical properties to optimize the final pipe yield strength.

Experimental Research on Effect of Hot Works on Mechanical Performance of Ship Steel Plate

2011 ◽  
Vol 311-313 ◽  
pp. 1859-1862
Author(s):  
Hua Ming Wang ◽  
Han Xing Zhao ◽  
Yong Jia Dai ◽  
Xiao Song Rui
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Steel Plate ◽  
Mechanical Performance ◽  
Structural Strength ◽  
High Strength ◽  
Shipbuilding Industry ◽  
Important Method ◽  
Fairing Process

Hot works is an important method for fairing the ship steel plate to improve the quality of shipbuilding, while the mechanical performance of the ship steel plate may be affected during the fairing process, which could result to some safe problems on the structural strength. DH32 high-strength ship steel plate, which is a kind of widely used material in shipbuilding industry, is taken as an object of the present experimental study. Some main parameters of the plate’s mechanical property through hot-works treatment for different times are investigated systematically. Through analyzing the variation of the mechanical properties, some conclusions are drawn and some useful suggestions put forward.

Evaluation of the Mechanical Performance of Woodball Mallet: A Finite Element Study

2011 ◽  
Vol 80-81 ◽  
pp. 1032-1034
Author(s):  
Yi Chen Lu ◽  
Yao Dong Gu
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Mechanical Performance ◽  
Proximal Part ◽  
Head Part ◽  
Element Analysis ◽  
Solid Models ◽  
The Finite Element Analysis ◽  
Maximal Stress ◽  
Element Study

This study aims to analyze the relevant mechanical properties of woodball shafts by applying numerical methods. The structures of woodball were constructed in Solidworks 2007 to form the solid models, and the numerical model was analyzed in ABAQUS to acquire the simulation resluts. The collision speed between ball and mallet was from the experiment of motion analysis. As the maximal stress of mallet was concentrated in the proximal part of bottle, some enforcement design could be carried out in this part to reduce the fracture incidence. Another important finding is the contact area at the mallet head was really small, the rubber cover at head part may thicken at the centre part and thinner at the outside area. For further study, it is important to represent the higher fidelity of the input conditions for the finite element analysis (FEA).

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