Considerations in Low-Temperature Mechanical Behavior of Polymer Composite Materials

2015 ◽  
Vol 760 ◽  
pp. 323-328
Author(s):  
Stefan Cotae ◽  
Constantin Popescu ◽  
Horatiu Iancau
Keyword(s):  
Tensile Strength ◽  
Mechanical Behavior ◽  
Fiber Orientation ◽  
Low Temperatures ◽  
Composite Structures ◽  
Room Temperature ◽  
Experimental Program ◽  
Independent Variables ◽  
Factorial Method ◽  
Degree Of Reinforcement

In this paper it has been sought to highlight the mechanical behavior of composite structures at low temperatures compared to mechanical behavior at room temperature. For researches an experimental program has been conceived and built using factorial method. In this method, as dependent variable was taken the tensile strength (σr), while as independent variables were taken: the fiber orientation angles (θ), the degree of reinforcement (Mf) of the composite structure and the temperature (t) at which the tests were carried out (+25°C,-25°C and-50°C respectively). It has been used a complex experimental installation, specific to tests at low temperatures.

Strength of Neoprene Compounds and the Effect of Salt Solutions

1983 ◽  
Vol 56 (4) ◽  
pp. 845-852 ◽  
Author(s):  
A. K. Bhowmick ◽  
A. N. Gent
Keyword(s):  
Tensile Strength ◽  
Lower Limit ◽  
Low Temperatures ◽  
Environmental Effect ◽  
Room Temperature ◽  
Characteristic Temperature ◽  
Salt Solutions ◽  
A Value ◽  
Fecl3 Solution ◽  
Tear Propagation

Abstract Soft CR vulcanizates resemble NR vulcanizates in many ways. Their tensile strength is high at low temperatures and drops sharply at a characteristic temperature to a value of about 1–1.5 MPa. Their tear resistance decreases smoothly as the temperature is raised and does not reach a lower limit, even at temperatures as high as 150°C. However, they show continuous tear propagation at room temperature under relatively large tear forces, whereas NR materials do not. This difference must reflect different strengths of the crystallites formed at the tear tip, those in CR being significantly weaker. Also, a specific environmental effect is noted: When immersed in solutions of FeCl3, the CR materials show more rapid tearing, and they tear at significantly lower forces than in water or in NaCl solutions (or in air). Although they swell continuously in water and in salt solutions, the rate of swelling seems far too low to account for the weakening observed. Moreover, the swelling is greater in water, whereas the weakening is specific to FeCl3 solution. It is attributed to a chemical reaction between FeCl3 and the CR molecule.

scholarly journals The influence of high and low temperatures on the impact properties of glass-epoxy composites

2007 ◽  
Vol 72 (7) ◽  
pp. 713-722 ◽  
Author(s):  
Slavisa Putic ◽  
Marina Stamenovic ◽  
Branislav Bajceta ◽  
Predrag Stajcic ◽  
Srdjan Bosnjak
Keyword(s):  
Low Temperatures ◽  
Composite Structures ◽  
Room Temperature ◽  
Epoxy Composite ◽  
Epoxy Composites ◽  
Temperature Influence ◽  
Impact Properties ◽  
Different Temperatures ◽  
High And Low Temperatures ◽  
The Impact

The aim of this paper is to present the influence of high and low temperatures on the impact properties glass-epoxy composites. The impact strength an is presented for four different glass-epoxy composite structures at three different temperatures, i.e., at room temperature t=20?C, at an elevated temperature t=+50?C and at a low temperature t=-50?C. Standard mechanical testing was carried out on the composite materials with specific masses of reinforcement of 210 g m-2 and 550 g m-2 and orientations 0?/90? and ?45?. Micromechanical analysis of the failure was performed in order to determine real models and mechanisms of crack and temperature influence on the impact properties. .

Mechanical Behavior of a Ni/TiC Microlaminate Under Static and Fatigue Loading

1996 ◽  
Vol 434 ◽  
Author(s):  
Y. C. Her ◽  
P. C. Wang ◽  
J.-M. Yang ◽  
R. F. Bunshah
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Mechanical Behavior ◽  
Layer Thickness ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Stiffness Reduction ◽  
Static And Cyclic Loading ◽  
The Relationship

AbstractThe mechanical behavior and damage mechanisms of the Ni/TiC microlaminate composites under static and cyclic loading were investigated. The relationship between the ultimate tensile strength and the layer thickness at both room temperature and 600°C was studied. The fatigue life and the evolution of the stiffness reduction under various maximum applied stress levels were determined. The results revealed that the ultimate tensile strength linearly increased as the laminate layer thickness decreased. Also, the microlaminate exhibited a non-progressive fatigue behavior.

Microstructural characterization and mechanical behavior of Cr25Ni35NbM alloy dissimilar weld joint for application in a hydrogen reformer furnace

2020 ◽  
Vol 117 (6) ◽  
pp. 612
Author(s):  
Jingfeng Guo ◽  
Wenwen Liu ◽  
Chunxiu Li ◽  
Xiaoming Zhang
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Weld Joint ◽  
Room Temperature ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Dissimilar Weld ◽  
Weld Joints

The microstructural characterization and mechanical behavior of Cr25Ni35NbM/15CrMo and Cr25Ni35NbM/SUS321 dissimilar weld joints were studied in this paper. The microstructure, room temperature and high temperature (1173 K) tensile strength of dissimilar weld joints were analyzed through optical microscopy (OM), scanning electron microscopy (SEM) and electronic universal tensile testing machine. The microstructure of HAZ in 15CrMo steel of Cr25Ni35NbM/15CrMo dissimilar weld joint transformed from ferrite-pearlite into ferrite-martensite. A large volume fraction of α phase was found to have precipitated in the HAZ of SUS321 austenitic stainless steel for Cr25Ni35NbM/SUS321 dissimilar weld joint. At room temperature, the tensile strength and yield strength of these two type dissimilar weld joints is less than Cr25Ni35NbM alloy similar weld joint. The high temperature tensile strength of these two type dissimilar weld joints is less than Cr25Ni35NbM alloy similar weld joint. Both at room and high temperature, the fracture locations of two types dissimilar weld joints are the HAZ of the base metal 15CrMo and SUS321 stainless steel, respectively. It indicates that the weak part of the Cr25Ni35NbM alloy dissimilar weld joints is the low-performance base metals 15CrMo and SUS321 stainless steel.

scholarly journals Optimasi kekuatan tarik komposit polyester diperkuat serat sisal dengan filler serbuk gergaji kayu sengon menggunakan metode respon surface

2016 ◽  
Vol 6 (2) ◽  
Author(s):  
IDK. Okariawan ◽  
M. Fajar ◽  
S. Hidayatullah
Keyword(s):  
Tensile Strength ◽  
Fiber Orientation ◽  
Volume Fraction ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Engineering Material ◽  
Independent Variables ◽  
New Material ◽  
Polyester Composites ◽  
Compaction Method

Composite is an engineering material, which is made from combination of two or more different materials into a new material with new properties. The aim of this research is to investigate optimum composition of sisal fiber reinforced sawdust sengon filled polyester composites on the tensile strength using respon surface methodology.The testing of tensile strength is based on ASTM D 3039 standard. It has dimension 6 mm in thick, 25 mm in width and 340 mm in length. The composites are made by using compaction method. The volume fraction of sisal fiber is 25%, 30% 35%, 40% and 45%. The ratio matrik with filler is varied 5, 10, 15, 20 and 25. The fiber length is 90 mm and the direction of fiber orientation is random.The results shows that the respon surface methodology capable to search value of independent variables to give optimum values of tensile strength. The application of respon surface methodology for the research optimation composition of sisal fiber reinforced sawdust sengon filled polyester composites on the tensile strength showed that the optimum value of tensile strength response could be achieved at volume fraction of sisal fiber 38,6565% and ratio matrik with filler 24,601.

Mechanical Behavior of 980MPa NANOHITENTM at Elevated Temperatures and its Effect on Springback in Warm Forming

2014 ◽  
Vol 611-612 ◽  
pp. 11-18 ◽  
Author(s):  
Toru Minote ◽  
Yoshimasa Funakawa ◽  
Naoko Saito ◽  
Mitsugi Fukahori ◽  
Hiroshi Hamasaki ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Stress Relaxation ◽  
Mechanical Behavior ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Warm Forming ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
High Tensile Strength

High tensile strength steel sheets have large springback after being formend at room temperature. Warm forming can be a solution to reduce springback of high tensile strength steel parts. NANOHITENTM is a high strength ferritic steel precipitation-strengthened by nanometer-sized carbides developed by JFE Steel Corporation. Tensile strength of the steel at room temperature does not change before and after deformation at elevated temperatures up to 873K since the carbides in the steel are stable at high temperatures less than 973K. Therefore, the steel is suitable for warm forming. Springback of 980MPa NANOHITENTM parts warm formed at 873K is the same level of that of cold formed conventional 590MPa steel parts. In this study, two kinds of material testing at room temperature and at elevated temperatures between 573K and 937K were performed to understand the mechanical behavior of 980MPa NANOHITENTM: uniaxial tensile tests and bending tests. The steels flow stress depends on not only material temperature but also strain rate in uniaxial tensile tests. After a bending test, the specimen shows springback measured by the change of an angle between the two sides. Stress relaxation happens while a test specimen is held at the bottom dead point after bending. And the stress relaxation could be used to reduce springback of warm formed parts.

Microstructure and physical properties of composite nonwovens produced by incorporating cotton fibers in elastic spunbond and meltblown webs for medical textiles

2021 ◽  
pp. 152808372110042
Author(s):  
Partha Sikdar ◽  
Gajanan S Bhat ◽  
Doug Hinchliff ◽  
Shafiqul Islam ◽  
Brian Condon
Keyword(s):  
Tensile Strength ◽  
Physical Properties ◽  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Barrier Properties ◽  
Cotton Fibers ◽  
Adult Care ◽  
Medical Textiles ◽  
Improved Performance

The objective of this research was to produce elastomeric nonwovens containing cotton by the combination of appropriate process. Such nonwovens are in demand for use in several healthcare, baby care, and adult care products that require stretchability, comfort, and barrier properties. Meltblown fabrics have very high surface area due to microfibers and have good absorbency, permeability, and barrier properties. Spunbonding is the most economical process to produce nonwovens with good strength and physical properties with relatively larger diameter fibers. Incorporating cotton fibers into elastomeric nonwovens can enhance the performance of products, such as absorbency and comfort. There has not been any study yet to use such novel approaches to produce elastomeric cotton fiber nonwovens. A hydroentangling process was used to integrate cotton fibers into produced elastomeric spunbond and meltblown nonwovens. The laminated web structures produced by various combinations were evaluated for their physical properties such as weight, thickness, air permeability, pore size, tensile strength, and especially the stretch recovery. Incorporating cotton into elastic webs resulted in composite structures with improved moisture absorbency (250%-800%) as well as good breathability and elastic properties. The results also show that incorporating cotton can significantly increase tensile strength with improved spontaneous recovery from stretch even after the 5th cycle. Results from the experiments demonstrate that such composite webs with improved performance properties can be produced by commercially used processes.

scholarly journals Review of Multi-Physics Modeling on the Active Magnetic Regenerative Refrigeration

2021 ◽  
Vol 26 (2) ◽  
pp. 47
Author(s):  
Julien Eustache ◽  
Antony Plait ◽  
Frédéric Dubas ◽  
Raynal Glises
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
Room Temperature ◽  
State Of The Art ◽  
Vapor Compression ◽  
Crucial Step ◽  
Potential Alternative ◽  
Vapor Compression Refrigeration ◽  
Preliminary Study ◽  
Physics Modeling

Compared to conventional vapor-compression refrigeration systems, magnetic refrigeration is a promising and potential alternative technology. The magnetocaloric effect (MCE) is used to produce heat and cold sources through a magnetocaloric material (MCM). The material is submitted to a magnetic field with active magnetic regenerative refrigeration (AMRR) cycles. Initially, this effect was widely used for cryogenic applications to achieve very low temperatures. However, this technology must be improved to replace vapor-compression devices operating around room temperature. Therefore, over the last 30 years, a lot of studies have been done to obtain more efficient devices. Thus, the modeling is a crucial step to perform a preliminary study and optimization. In this paper, after a large introduction on MCE research, a state-of-the-art of multi-physics modeling on the AMRR cycle modeling is made. To end this paper, a suggestion of innovative and advanced modeling solutions to study magnetocaloric regenerator is described.

scholarly journals On the measurement of the ratio of the specific heats using small volumes of gas.—The ratios of the specific heat of air and of hydrogen at atmospheric pressure and a temperatures between 20°C. and —183°C

1925 ◽  
Vol 107 (743) ◽  
pp. 510-543 ◽  
Keyword(s):  
Systematic Error ◽  
Low Temperatures ◽  
Room Temperature ◽  
Expansion Chamber ◽  
Small Vessels ◽  
Specific Heats ◽  
Large Expansion ◽  
Before And After ◽  
The One ◽  
Chamber Capacity

Introduction .—In nearly all the previous determinations of the ratio of the specific heats of gases, from measurements of the pressures and temperature before and after an adiabatic expansion, large expansion chambers of fror 50 to 130 litres capacity have been used. Professor Callendar first suggests the use of smaller vessels, and in 1914, Mercer (‘Proc. Phys. Soc.,’ vol. 26 p. 155) made some measurements with several gases, but at room temperature only, using volumes of about 300 and 2000 c. c. respectively. He obtained values which indicated that small vessels could be used, and that, with proper corrections, a considerable degree of accuracy might be obtained. The one other experimenter who has used a small expansion chamber, capacity about 1 litre, is M. C. Shields (‘Phys. Rev.,’ 1917), who measured this ratio for air and for hydrogen at room temperature, about 18° C., and its value for hydroger at — 190° C. The chief advantage gained by the use of large expansion chambers is that no correction, or at the most, a very small one, has to be made for any systematic error due to the size of the containing vessels, but it is clear that, in the determinations of the ratio of the specific heats of gases at low temperatures, the use of small vessels becomes a practical necessity in order that uniform and steady temperature conditions may be obtained. Owing, however, to the presence of a systematic error depending upon the dimensions of the expansion chamber, the magnitude of which had not been definitely settled by experiment, the following work was undertaken with the object of investigating the method more fully, especially with regard to it? applicability to the determination of this ratio at low temperatures.

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