scholarly journals Crimp in Wool: Cortical Segmentation and Tensile Properties of Well-Crimped and Abnormally Crimped Fibres of Merino Wool

1965 ◽  
Vol 18 (3) ◽  
pp. 689 ◽  
Author(s):  
RE Chapman
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Deficient Diet ◽  
Outer Root Sheath ◽  
Merino Wool ◽  
Root Sheath ◽  
Breaking Points

Poorly crimped (or doggy) fibres, produced by follicles with hyperplasia of the outer root sheath tissue, have greater proportions of paracortex than adjacent well-crimped fibres. Associated with this increase in paracortex is an increase in strength, as indicated by significant increases in the stresses in wet poorly crimped fibres at the turnover and breaking points on the stress-strain curve. Use of the stronger mechanical properties of doggy fibres as a means of distinguishing such fibres from the poorly crimped fibres in steely wool, produced by sheep on a copper-deficient diet, is proposed.

Mechanical properties of UN-5100 envelope material for stratospheric airship

2020 ◽  
pp. 1-17
Author(s):  
W.-c. Xie ◽  
X.-l. Wang ◽  
D.-p. Duan ◽  
J.-w. Tang ◽  
Y. Wei
Keyword(s):  
Mechanical Properties ◽  
Significant Role ◽  
Strain Curve ◽  
Image Correlation ◽  
Membrane Structures ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Biaxial Tensile ◽  
Envelope Material ◽  
Biaxial Tensile Testing

ABSTRACT Stratospheric airships are promising aircraft, usually designed as a non-rigid airship. As an essential part of the non-rigid airship, the envelope plays a significant role in maintaining its shape and bearing the external force load. Generally, the envelope material of a flexible airship consists of plain-weave fabric, composed of warp and weft fibre yarn. At present, biaxial tensile experiments are the primary method used to study the stress–strain characteristics of such flexible airship materials. In this work, biaxial tensile testing of UN-5100 material was carried out. The strain on the material under unusual stress and the stress ratio were obtained using Digital Image Correlation (DIC) technology. Also, the stress–strain curve was corrected by polynomial fitting. The slope of the stress–strain curve at different points, the Membrane Structures Association of Japan (MSAJ) standard and the Radial Basis Function (RBF) model were compared to identify the stress–strain characteristics of the materials. Some conclusions on the mechanical properties of the flexible airship material can be drawn and will play a significant role in the design of such envelopes.

Experimental Research on the Stress - Strain Curve of Regional Confined Concrete under Single Axial Press

2014 ◽  
Vol 584-586 ◽  
pp. 1289-1292
Author(s):  
Guo Liang Zhu
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Constitutive Model ◽  
Theoretical Basis ◽  
Strain Curve ◽  
Confined Concrete ◽  
Constitutive Relationship ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Relationship Of

Regional confined concrete is base on confined concrete. It is the theory and application of a new attempt and development on confined concrete. To apply it to the actual project, we need to research mechanical properties and establish constitutive relationship of regional confined concrete. According to the research, we had carried on a series of tests, founded the stress-strain constitutive model of regional confined concrete under single axial press. The accuracy of theoretical analysis were more fully verified , and a theoretical basis for the application was provided.

scholarly journals Hybrid-modelling of Mechanical Properties and Thermo-mechanical Behaviour of Chopped Strand Mat Reinforced Thermoset Composites

2020 ◽  
pp. 1-14
Author(s):  
Cornelius Ogbodo Anayo Agbo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behaviour ◽  
Strain Curve ◽  
Fibre Volume ◽  
Secant Modulus ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hybrid Modelling ◽  
Thermoset Composites ◽  
Chopped Strand Mat

The concern of this paper is to develop simple workshop application models for predicting the mechanical properties and the evaluation of the thermo-mechanical behaviour of chopped strand fibre-mat reinforced thermoset composites. A hybrid of empirical and strength of materials approach was used at macro- and micro-mechanics levels to model the random fibres which were treated as simple bars within the mat preform and the resulting composite material. The model was validated experimentally by testing wet lay-up produced samples with varying fibre volume fractions and they were found to agree well. The toughness modulus of the composite was also modeled using the secant modulus obtained from the sample’s stress – strain curves of uniform material composites produced at different temperature histories. The toughness modulus determined using the new model was compared with that obtained using the area under the same stress – strain curve computed by Simpson’s rule and the results agreed very well.

Experimental Research on Deformation Properties of Gangue-Paste Filling Material in Mine

2013 ◽  
Vol 734-737 ◽  
pp. 746-750
Author(s):  
Jun Wei Shi
Keyword(s):  
Mechanical Properties ◽  
Uniaxial Compression ◽  
Triaxial Compression ◽  
Strain Curve ◽  
Filling Material ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Deformation Stage ◽  
Plastic Hardening ◽  
Softening Stage

According to the mechanical properties of paste filling body under special environment such as high temperature high humidity high stress and high airtight) in gob, mechanical properties of gangue-paste filling body was studied with the method of field core and laboratory test. The complete stress-strain curve of filling body under the condition of uniaxial and triaxial and the ultimate compressive strength under different confining pressure station were obtained through uniaxial and triaxial compression test. Six stages of uniaxial compression complete stress-strain curve (compression stage, elastic deformation stage, non-stable developing stages, plastic hardening stage, stress softening stage and residual deformation stage) were improved and developed. The deformation characteristics of filling body under triaxial compression were different from that under uniaxial compression. Namely the deformation of filling body under triaxial compression only appeared two deformation stages: linear deformation stage and plastic hardening stage, but had no softening stage basically under different confining pressures, which was benefit for controlling the ground subsidence and preventing the ground buildings.

The Effect of Nitrogen and Inoculation on the Tensile Properties and Microstructure of Cast Iron with Lamellar Graphite

2010 ◽  
Vol 457 ◽  
pp. 114-119 ◽  
Author(s):  
Fredrik Wilberfors ◽  
Ingvar L. Svensson
Keyword(s):  
Cast Iron ◽  
Plastic Strain ◽  
Tensile Properties ◽  
Cell Size ◽  
Deformation Behaviour ◽  
Strain Curve ◽  
Eutectic Cell ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Lamellar Graphite

The main purpose with this paper is to show the effect of nitrogen and inoculation on the tensile properties and microstructure of cast iron with lamellar graphite. Casting experiments were performed with the main composition: 3.4 % C, 2.0 % Si, 0.7 % Mn, 0.5 % Cu. The nitrogen content was varied between 90-180 ppm and inoculant was added as 0, 0.2 or 0.4 % by weight. The addition of inoculant changed the graphite structure from distribution D/B/A to distribution A, according to ISO 945. The eutectic cell size decreased significantly. The addition of inoculant had no influence on the hardness. The addition of nitrogen shortened the graphite flakes and increased the hardness. The influence on the eutectic cell size was low and there was no significant effect on the graphite distribution. Tensile test samples were analysed by true stress – true plastic strain in terms of the flow relationships proposed by Hollomon, , and Ludwigson, . The stress-strain curves were fitted to polynomial functions of the 6:th to 8:th order before evaluating the constants in order to eliminate noise from the measurements. This approach also enabled the slope of the stress-strain curve to be evaluated at zero stress (Young’s modulus), resulting in plastic strain from stress levels close to zero. The Hollomon flow relationship failed to describe the deformation behaviour for the whole range of the stress-strain curve. The correction terms in the Ludwigson flow relationship resulted in a better fit. The addition of inoculant mainly affected the strength coefficient, . The addition of nitrogen also affected the constant. The main reason for this was that the addition of inoculant influenced the last part of the stress-strain curve while the addition of nitrogen had an effect over the whole range of the curve. The addition of nitrogen and inoculant increased the tensile strength from 288 MPa to 393 MPa and the total elongation at fracture from 0.8 % to 1.6 %.

The Research of Test on Stress-Strain Constitutive Relations of Straw Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 987-992
Author(s):  
Wei Liu ◽  
Wei Xi ◽  
Yi Lu Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Constitutive Relations ◽  
Strain Curve ◽  
Green Building ◽  
Corn Straw ◽  
Stress Strain Curve ◽  
Stress Strain

As a new green building material, straw concrete are introduced about its mechanical properties and characteristics. Mechanical properties test such as prism compressive strength, elastic modulus and Poisson's ratios use standard prismatic blocks. Under different rate of corn straw, cement, sand and fly ash, test gets the full stress-strain curve. Results show that with increase of volume of corn straw, the prism compressive strength reduces significantly. Comparing with natural concrete, elastic modulus of straw concrete can reduces greatly. Poisson’s ratio reduces with increase of volume of corn straw. Fly ash could improve property of the material and replace cement, but excessive replacement will reduce the strength of material.

Experimental Study on Full Stress-Strain Curve of SFRC in Axial Tension

2012 ◽  
Vol 238 ◽  
pp. 41-45
Author(s):  
Hong Yuan Huo ◽  
Chen Jie Cao ◽  
Li Sun ◽  
Li Sha Song ◽  
Tong Xing
Keyword(s):  
Tensile Properties ◽  
Cement Paste ◽  
Steel Fiber ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Axial Tension ◽  
Axial Tensile

The tests were carried out to study the effects of the fraction of steel fiber by volume and the thickness of cement paste wrapping steel fibers on the axial tensile properties of steel fiber reinforced concrete (SFRC). The strength grade of SFRC was CF40 with the fraction of steel fiber by volume varying from 0.5% to 2.0%, and the thickness of cement paste wrapping steel fibers varying from 0.8mm to 1.2mm. The tests were conducted by WAW-600 electric-hydraulic servo-type test machine. The results show that the axial tensile properties such as the axial tensile strength, the fullness of stress-strain curve, the tensile energy and the axial tensile toughness ratio are all improved obviously by the adding of steel fiber in concrete. The reasonable thickness of cement paste wrapping steel fibers is 1.0mm. The formulas for stress-strain relationship of SFRC in axial tension are proposed.

Experimental Setup for the Determination of Mechanical Solder Materials Properties at Elevated Temperatures

2010 ◽  
Vol 638-642 ◽  
pp. 3793-3798
Author(s):  
Wolfgang H. Müller ◽  
Holger Worrack ◽  
Jens Sterthaus
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
Linear Optimization ◽  
Strain Curve ◽  
Stress And Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Non Linear

The fabrication of microelectronic and micromechanical devices leads to the use of only very small amounts of matter, which can behave quite differently than the corresponding bulk. Clearly, the materials will age and it is important to gather information on the (changing) material characteristics. In particular, Young’s modulus, yield stress, and hardness are of great interest. Moreover, a complete stress-strain curve is desirable for a detailed material characterization and simulation of a component, e.g., by Finite Elements (FE). However, since the amount of matter is so small and it is the intention to describe its behavior as realistic as possible, miniature tests are used for measuring the mechanical properties. In this paper two miniature tests are presented for this purpose, a mini-uniaxial-tension-test and a nanoindenter experiment. In the tensile test the axial load is prescribed and the corresponding extension of the specimen length is recorded, both of which determines the stress-strain- curve directly. The stress-strain curves are analyzed by assuming a non-linear relationship between stress and strain of the Ramberg-Osgood type and by fitting the corresponding parameters to the experimental data (obtained for various microelectronic solders) by means of a non-linear optimization routine. For a detailed analysis of very local mechanical properties nanoindentation is used, resulting primarily in load vs. indentation-depth data. According to the procedure of Oliver and Pharr this data can be used to obtain hardness and Young’s modulus but not a complete stress-strain curve, at least not directly. In order to obtain such a stress-strain-curve, the nanoindentation experiment is combined with FE and the coefficients involved in the corresponding constitutive equations for stress and strain are obtained by means of the inverse method. The stress-strain curves from nanoindentation and tensile tests are compared for two mate-rials (aluminum and steel). Differences are explained in terms of the locality of the measurement. Finally, material properties at elevated temperature are of particular interest in order to characterize the materials even more completely. We describe the setup for hot stage nanoindentation tests in context with first results for selected materials.

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