scholarly journals Microstructural evolution of regenerated silk fibroin/graphene oxide hybrid fibers under tensile deformation

RSC Advances ◽  
2017 ◽  
Vol 7 (6) ◽  
pp. 3108-3116 ◽  
Author(s):  
Chao Zhang ◽  
Yaopeng Zhang ◽  
Jie Luo ◽  
Jingru Shi ◽  
Huili Shao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Silk Fibroin ◽  
Tensile Deformation ◽  
Strain Curve ◽  
Microstructural Change ◽  
Stress Strain Curve ◽  
Hybrid Fibers ◽  
Proposed Model ◽  
Regenerated Silk Fibroin ◽  
Stretching Deformation

The stress–strain curve and proposed model of microstructural change of silk fibroin/GO hybrid fibers during the stretching deformation.

Effect of Draw Ratio on the Microstructure of Silk Fibroin/Graphene Oxide Hybrid Fibers

2017 ◽  
Vol 898 ◽  
pp. 2214-2223
Author(s):  
Chao Zhang ◽  
Hui Li Shao ◽  
Xue Chao Hu ◽  
Yao Peng Zhang
Keyword(s):  
Graphene Oxide ◽  
Silk Fibroin ◽  
High Performance ◽  
Draw Ratio ◽  
Structure Evolution ◽  
Structure Property ◽  
Hybrid Fibers ◽  
Initial Modulus ◽  
Regenerated Silk Fibroin ◽  
Breaking Energy

In order to fabricate high performance artificial silk, hybrid fibers were dry spun from regenerated silk fibroin (RSF) aqueous solution mixed with graphene oxide (GO) nanosheets. The influence of draw ratio on the microstructure and mechanical properties of RSF/GO hybrid fibers was studied through Fourier transform infrared spectroscopy (FT-IR), synchrotron radiation wide-angle X-ray diffraction, Raman spectroscopy and mechanical testing. The results showed that with increasing draw ratio, both amorphous phase and mesophase of the dry-spun artificial fiber gradually converted to crystals. The orientation of crystals and mesophase changed slightly at low draw ratio, but increased significantly at draw ratios of 3 and 4X. The β-sheet content of silk fibroin and the disorder degree of GO sheets in the fibers also increased with the increase of draw ratio. The initial modulus, breaking strength and breaking energy of the hybrid fibers achieved great improvement at a draw ratio of 4X. The structure evolution of the RSF/GO hybrid fibers may benefit the understanding of the structure-property relationship of other composite fibers.

scholarly journals Modelling of the behaviour of metal foams under shock compression

2018 ◽  
Vol 183 ◽  
pp. 01041
Author(s):  
Nicolas Jacques ◽  
Romain Barthélémy
Keyword(s):  
Experimental Data ◽  
Excellent Agreement ◽  
Strain Curve ◽  
Metal Foams ◽  
Cellular Materials ◽  
Theoretical Modelling ◽  
Stress Strain Curve ◽  
Open Cell ◽  
Proposed Model ◽  
Shock Response

A theoretical modelling is proposed to describe the shock response of foam materials. This model is based on micromechanical and energetic arguments, and takes into account the contribution of microscale inertia. Within this framework, an analytical expression of the Hugoniot stress-strain curve is proposed for elastic-plastic cellular materials. The predictions derived from the proposed model are in excellent agreement with experimental data for open-cell aluminium foams. The case of viscoplastic foams is also considered.

Hybrid Silk Fibers Dry-Spun from Regenerated Silk Fibroin/Graphene Oxide Aqueous Solutions

2016 ◽  
Vol 8 (5) ◽  
pp. 3349-3358 ◽  
Author(s):  
Chao Zhang ◽  
Yaopeng Zhang ◽  
Huili Shao ◽  
Xuechao Hu
Keyword(s):  
Graphene Oxide ◽  
Aqueous Solutions ◽  
Silk Fibroin ◽  
Silk Fibers ◽  
Regenerated Silk Fibroin

Mechanical Behavior of Materials under Tensile Loads

2004 ◽  
pp. 13-31
Keyword(s):  
Tensile Test ◽  
Mechanical Behavior ◽  
Tensile Deformation ◽  
True Strain ◽  
Strain Curve ◽  
Tensile Specimen ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Mathematical Expressions ◽  
Reduction In Area

Abstract This chapter focuses on mechanical behavior under conditions of uniaxial tension during tensile testing. It begins with a discussion on the parameters that are used to describe the engineering stress-strain curve of a metal, namely, tensile strength, yield strength or yield point, percent elongation, and reduction in area. This is followed by a section describing the parameters determined from the true stress-true strain curve. The chapter then presents the mathematical expressions for the flow curve. Next, it reviews the effect of strain rate and temperature on the stress-strain curve. The chapter then describes the instability in tensile deformation and stress distribution at the neck in the tensile specimen. It discusses the processes involved in ductility measurement and notch tensile test in tensile specimens. The parameter that is commonly used to characterize the anisotropy of sheet metal is covered. Finally, the chapter covers the characterization of fractures in tensile test specimens.

scholarly journals A Stress-Strain Model for Brick Prism under Uniaxial Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Yongjei Lee ◽  
Yong-Ha Hwang
Keyword(s):  
Strain Curve ◽  
Peak Stress ◽  
Test Results ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Proposed Model ◽  
Relationship Model ◽  
Strain Relationship ◽  
Strain Model

This study proposes a simple and rational stress-strain relationship model applicable to brick masonry under compression. The brick prism compression tests were conducted with different mortar strengths and with constant brick strength. From the observation of the test results, shape of the stress-strain curve is assumed to be parabola. In developing the stress-strain model, the modulus of elasticity, the strain at peak stress, and the strain at 50% of the peak stress on the descending branch were formulated from regression analysis using test data. Numerical and statistical analyses were then performed to derive equations for the key parameter to determine the slopes at the ascending and descending branches of the stress-strain curve shape. The reliability of the proposed model was examined by comparisons with actual stress-strain curves obtained from the tests and the existing model. The proposed model in this study turned out to be more accurate and easier to handle than previous models so that it is expected to contribute towards the mathematical simplicity of analytical modeling.

Modelling of the Strain Hardening Behaviour of Die-Cast Magnesium-Aluminium-Rare Earth Alloy

2020 ◽  
Vol 35 ◽  
pp. 1-8
Author(s):  
Hua Qian Ang
Keyword(s):  
Strain Hardening ◽  
Tensile Deformation ◽  
Deformation Behaviour ◽  
Strain Curve ◽  
Deformation Mode ◽  
Prismatic Slip ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Die Cast ◽  
Cast Magnesium

The tensile deformation behaviour of magnesium alloy AE44 (Mg-4Al-4RE) under strain rates ranging from 10-6 to 10-1 s-1 has been investigated. Present study shows that the deformation mode begins with the activation of elastic (Stage 1), followed by <a> basal slip and twinning (Stage 2), <a> prismatic slip (Stage 3) and finally to <c+a> pyramidal slip (Stage 4). The commencement of these deformation mechanisms results in four distinct stages of strain hardening in the stress-strain curve. In this work, the four stages of deformation behaviour are modelled, and an empirical equation is proposed to predict the entire stress-strain curve. Overall, the model predictions are in good agreement with the experimental data. This study on the decomposition of stress-strain curve into four stages provides insights into the contribution of individual deformation mechanism to the overall deformation behaviour and opens a new way to assess mechanical properties of die-cast magnesium alloys.

A Mathematical Model of Lung Parenchyma

1980 ◽  
Vol 102 (2) ◽  
pp. 124-136 ◽  
Author(s):  
A. D. Karakaplan ◽  
M. P. Bieniek ◽  
R. Skalak
Keyword(s):  
Strain Energy ◽  
Strain Energy Function ◽  
Strain Curve ◽  
Lung Parenchyma ◽  
The Finite Element Method ◽  
Stress Strain Curve ◽  
Proposed Model ◽  
Elastic Membranes ◽  
Mammalian Lung ◽  
Nonlinear Elastic

The geometry of the proposed model of the parenchyma of a mammalian lung reproduces a cluster of alveoli arranged around a lowest-level air duct. The alveolar walls are assumed to be nonlinear elastic membranes, whose properties are described in terms of a strain energy function which reflects the hardening character of the stress-strain curve. The effect of the surfactant is included in terms of a variable (area-dependent) surface tension. Analyses of various mechanical processes in the parenchyma are performed with the aid of the finite element method, with the geometric and physical nonlinearities of the problem taken into account.

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