scholarly journals Temperature-Dependent Creep Behavior and Quasi-Static Mechanical Properties of Heat-Treated Wood

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 968
Author(s):  
Dong Xing ◽  
Xinzhou Wang ◽  
Siqun Wang
Keyword(s):  
Mechanical Properties ◽  
Creep Behavior ◽  
Cell Walls ◽  
Treated Wood ◽  
Crosslinking Reaction ◽  
Depth Sensing ◽  
Temperature Dependent ◽  
Heat Treated ◽  
Static Mechanical ◽  
Static Mechanical Properties

In this paper, Berkovich depth-sensing indentation has been used to study the effects of the temperature-dependent quasi-static mechanical properties and creep deformation of heat-treated wood at temperatures from 20 °C to 180 °C. The characteristics of the load–depth curve, creep strain rate, creep compliance, and creep stress exponent of heat-treated wood are evaluated. The results showed that high temperature heat treatment improved the hardness of wood cell walls and reduced the creep rate of wood cell walls. This is mainly due to the improvement of the crystallinity of the cellulose, and the recondensation and crosslinking reaction of the lignocellulose structure. The Burgers model is well fitted to study the creep behavior of heat-treated wood cell walls under different temperatures.

Effect of Deep Cryogenic Treatment on the Microstructure of an Aerospace Aluminum Alloy

2012 ◽  
Vol 445 ◽  
pp. 965-970 ◽  
Author(s):  
F. Bouzada ◽  
M. Cabeza ◽  
P. Merino ◽  
S. Trillo
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Grain Boundaries ◽  
Cryogenic Treatment ◽  
Deep Cryogenic Treatment ◽  
Heat Treated ◽  
Static Mechanical ◽  
Compressive Residual Stresses ◽  
Static Mechanical Properties

This paper describes how deep cryogenic treatment at 98K produces changes in the microstructure of a heat-treated aluminum alloy. It was observed how the sub-micrometric particles increased near and at the grain boundaries. This slight precipitation did not produce any modification in static mechanical properties. However, the compressive residual stresses of the material were higher after compared to before the treatment. Both these effects can enhance the life of this alloy through cryogenic treatment.

Light-Induced Structural Relaxation and the Photoplastic Effect in Chalcogenide Glasses

2006 ◽  
Vol 115 ◽  
pp. 245-250 ◽  
Author(s):  
M.L. Trunov ◽  
Sergey N. Dub ◽  
R.S. Shmegera
Keyword(s):  
Mechanical Properties ◽  
Flow Stress ◽  
Structural Relaxation ◽  
Chalcogenide Glasses ◽  
Light Illumination ◽  
Depth Sensing ◽  
Static Mechanical ◽  
Photoplastic Effect ◽  
Photoinduced Changes ◽  
Static Mechanical Properties

The combination of depth-sensing indentation and band-gap illumination has been used to study the photoplastic effect (the reversible influence of light on the flow stress, hardness, and plasticity) in chalcogenide glasses on a nanoscale. The prominent photoplasticity of thin As-Se films has been revealed through deviations in the shape of load-displacement curves during nanoindentation under light illumination from those ones which have been observed for the material in the darkness. The photoinduced changes in static mechanical properties such as nanohardness and elastic (Young’s) modulus have been determined. The highest photoplasticity changes are achieved for As20Se80 films while their photodarkening is the lowest.

Quasi-static mechanical properties of novel generalized Resch-pattern composite foldcores

2020 ◽  
pp. 095440622094000
Author(s):  
Antao Deng ◽  
Bin Ji ◽  
Xiang Zhou
Keyword(s):  
Mechanical Properties ◽  
Design Method ◽  
Absorption Capacity ◽  
Woven Fabrics ◽  
Geometric Design ◽  
Honeycomb Core ◽  
Reinforced Plastic ◽  
Static Mechanical ◽  
Laminate Thickness ◽  
Static Mechanical Properties

A new geometric design method for foldcores based on the generalized Resch patterns that allow face-to-face bonding interfaces between the core and the skins is proposed. Based on the geometric design method, a systematic numerical investigation on the quasi-static mechanical properties of the generalized Resch-based foldcores made of carbon fiber-reinforced plastic (CFRP) woven fabrics subjected to compression and shear loads is performed using the finite element method that is validated by experiments. The relationships between the mechanical properties and various geometric parameters as well as laminate thickness of the generalized Resch-based CFRP foldcores are revealed. Additionally, the mechanical properties of the generalized Resch-based CFRP foldcore are compared to those of the standard Resch-based, Miura-based foldcore, the honeycomb core, and the aluminum counterpart. It is found that the generalized Resch-based CFRP foldcore performs more stably than the honeycomb core under compression and has higher compressive and shear stiffnesses than the standard Resch-based and Miura-based foldcores and absorbs as nearly twice energy under compression as the Miura-based foldcore does. When compared with the aluminum counterpart, the CFRP model has higher weight-specific stiffness and strength but lower energy absorption capacity under shearing. The results presented in this paper can serve as the useful guideline for the design of the generalized Resch-based composite foldcore sandwich structures for various performance goals.

A Study on Estimation of S-N Curves for Structural Steels Based on their Static Mechanical Properties

2014 ◽  
Vol 891-892 ◽  
pp. 1639-1644 ◽  
Author(s):  
Kazutaka Mukoyama ◽  
Koushu Hanaki ◽  
Kenji Okada ◽  
Akiyoshi Sakaida ◽  
Atsushi Sugeta ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Evaluation Method ◽  
Materials Science ◽  
Estimation Method ◽  
Structural Steels ◽  
Metallic Materials ◽  
Fatigue Reliability ◽  
Regression Parameters ◽  
Static Mechanical ◽  
Static Mechanical Properties

The aim of this study is to develop a statistical estimation method of S-N curve for iron and structural steels by using their static mechanical properties. In this study, firstly, the S-N data for pure iron and structural steels were extracted from "Database on fatigue strength of Metallic Materials" published by the Society of Materials Science, Japan (JSMS) and S-N curve regression model was applied based on the JSMS standard, "Standard Evaluation Method of Fatigue Reliability for Metallic Materials -Standard Regression Method of S-N Curve-". Secondly, correlations between regression parameters and static mechanical properties were investigated. As a result, the relationship between the regression parameters and static mechanical properties (e.g. fatigue limit E and static tensile strength σB) showed strong correlations, respectively. Using these correlations, it is revealed that S-N curve for iron and structural steels can be predicted easily from the static mechanical properties.

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