Determination of Fracture Behavior under Biaxial Loading of Kevlar 149

2015 ◽  
Vol 766-767 ◽  
pp. 1127-1132 ◽  
Author(s):  
S. Manigandan
Keyword(s):  
Fracture Behavior ◽  
Biaxial Loading ◽  
High Strength ◽  
Flame Resistance ◽  
Flat Plates ◽  
Standard Size ◽  
Effective Utilization ◽  
Different Types ◽  
Effective Reinforcement

The high crystalline fiber Kevlar 149 has a major industrial application and it is extensively used in aerospace industries due to its significant properties of ultra-high modulus, high strength, low density, high flame resistance. Kevlar 149 has an advantage over K 49, since it absorbs less moisture and has high compression strength [3]. In order to explore the vast application, this paper investigates the fracture response of the Kevlar material computationally, when they are subjected to biaxial loading in both tensile and compression. This loading is done to understand the response of the Kevlar how far they poor in compression and rich in tensile. The fiber induced with epoxy is to form as an effective reinforcement. Here the fiber taken as Kevlar 149 & K-49 and the epoxy resin. For easy understanding a sample of two flat plates is considered as a composite structure of standard size, which under goes the biaxial loading computationally using Abaqus/CAE. The pictorial data’s are taken from the post processing study and the data’s can be used to investigate the fracture mechanism of Kevlar 149 & K-49, under different types of strain loading. The output results of Kevlar 149 is compared with K-49 to analyze the behavior of fiber undergoes the biaxial loading both compressive and tensile and also the merits and effective utilization of K-149. It is suggested that this method can be applied to other type of composite materials.

How to Enhance Efficiency and Accuracy of the Over-Deterministic Method Used for Determination of the Coefficients of the Higher-Order Terms in Williams Expansion

2012 ◽  
Vol 245 ◽  
pp. 120-125 ◽  
Author(s):  
Lucie Šestáková
Keyword(s):  
Fracture Behavior ◽  
Accurate Determination ◽  
Higher Order ◽  
Elastic Behavior ◽  
Deterministic Method ◽  
Effective Utilization ◽  
Higher Order Terms ◽  
Enhance Efficiency ◽  
Extended Zone

Using higher-order terms of the Williams expansion is necessary for assessment of fracture behavior of quasi-brittle materials. Multi-parameter fracture mechanics enables more accurate determination of the stress/displacement field even in a larger distance from the crack tip, thus the extended zone with non-elastic behavior typical for this kind of material can be well described. The so-called over-deterministic method (ODM) seems to be a suitable tool for the higher-order terms coefficients calculation, but its utilization exhibits some limitations. Therefore, extensive analyses have been performed in order to summarize recommendations regarding the mesh sensitivity, boundary conditions influence, etc. List of pieces of advice and author’s experiences presented in the end of this work should contribute to more accurate and effective utilization of the ODM.

scholarly journals Straightening of low-rigid cylindrical details. Part I. Justification of the type of loading and modes at transverse straightening

2019 ◽  
Vol 62 (7) ◽  
pp. 517-524 ◽  
Author(s):  
S. A. Zaides ◽  
Kuang Le Khong
Keyword(s):  
Extreme Values ◽  
Initial Deflection ◽  
Mathematical Apparatus ◽  
Flat Plates ◽  
Residual Tension ◽  
Different Types ◽  
Definition Of ◽  
Loading Type ◽  
Ansys Workbench

For straightening of low-rigid cylindrical details like shaft and axes different types of loadings are considered which form tension different in size and in distribution. As the perspective direction, it is possible to consider correction by a bend at the influence of the distributed loading with the subsequent hardening of a billet by superficial plastic deformation based on a cross cheesing of it by flat plates. Purpose of the work was to define tension of the billet at cross correction for the choice of more effective type of loading and processing rational modes. The mathematical apparatus was used based on laws of the theory of an elastoplastic solid and Ansys Workbench software package. Novelty is the research of effective methods of loading at cross correction of cylindrical details. As a result of analytical calculations, value of the residual tension providing correction of cylindrical details was determined. Residual tension necessary for correction of cylindrical details depends on an initial deflection, material and preparation rate. Tension of cylindrical details was defined depending on a type of the application of cross loadings. Bend tension for correction of a shaft at distributed loading is less, than tension from action of cross force. For correction of a shaft with a diameter of 10 mm, 200  mm long and an initial deflection of 0.5  mm it is necessary to create bend tension equal to about 370  MPa. An effective method of loading at cross correction of cylindrical details is the bend at influence of the distributed loading. The received extreme values of bend coefficients are from 5.3 to 5.5 for all cases of shaft rigidity at correction by cross bend at distributed loading with l/L relation equal to 0.8. The developed mathematical model gives quite reliable values of the residual tension providing correction of cylindrical details. The analytical dependence for determination of the size of general deflections and definition of an effective loading type can be recommended for practical use in production for achievement of precision accuracy of low-rigid details like shaft.

Fracture Behavior of Pressurized Defective Pipes Subjected to Large Tensile Strains

2015 ◽  
Author(s):  
Marcelo Paredes ◽  
Tomasz Wierzbicki
Keyword(s):  
Stress State ◽  
Loading Condition ◽  
Fracture Behavior ◽  
Biaxial Loading ◽  
Tensile Load ◽  
Complex Loading ◽  
Loading Mode ◽  
Coulomb Criterion ◽  
Growing Cracks

In this work the tensile capacity of circumferentially pressurized cracked pipes with varying crack parameters and pipe dimensions are numerically investigated. The biaxial loading mode includes internal pressure and tensile load, which are applied in sequence. The present physics-inspired fracture model based upon the original Mohr-Coulomb criterion enables not only the computation of global fracture response of pipe subjected to complex loading condition but also a thorough determination of the local evolving stress state around the growing cracks.

Characterization of Different Types of Biomass Wastes Using Thermogravimetric and ICP-MS Analyses

2020 ◽  
Vol 70 (12) ◽  
pp. 4594-4600
Keyword(s):  
Thermogravimetric Analysis ◽  
Food Industry ◽  
Wood Waste ◽  
Biomass Ash ◽  
Minor Elements ◽  
Ms Analysis ◽  
Icp Ms ◽  
Different Types

The purpose of this study was to characterize some types of biomass wastes resulted from different activities such as: agriculture, forestry and food industry using thermogravimetric and ICP-MS analyses. Also, it was optimized an ICP-MS method for the determination of As, Cd and Pb from biomass ash samples. The ICP-MS analysis revealed that the highest concentration of metals (As, Cd, Pb) was recorded in the wood waste ash sample, also the thermogravimetric analysis indicated that the highest amount of ash was obtained for the same sample (26.82%). The biomass wastes mentioned in this study are alternative recyclable materials, reusable as pellets and briquettes. Keywords: ash, biomass, ICP-MS, minor elements, TG

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

Loading rate effect on fracture behavior of fiber reinforced high strength concrete using a semi-circular bending test

2020 ◽  
Vol 240 ◽  
pp. 117681
Author(s):  
Mehran Aziminezhad ◽  
Sahand Mardi ◽  
Pouria Hajikarimi ◽  
Fereidoon Moghadas Nejad ◽  
Amir H. Gandomi
Keyword(s):  
High Strength Concrete ◽  
Fracture Behavior ◽  
Loading Rate ◽  
High Strength ◽  
Rate Effect ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Strength Concrete
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