The mechanical behaviors and energy absorption mechanisms of Al–Cu–Mn alloy under dynamic penetration at wide temperature ranges and large angles

2020 ◽  
Vol 815 ◽  
pp. 152188 ◽  
Author(s):  
Ping Zhang ◽  
Youqiang Wang ◽  
Xiao Yu ◽  
Heng Luo
Keyword(s):  
Energy Absorption ◽  
Mechanical Behaviors ◽  
Temperature Ranges ◽  
Dynamic Penetration

scholarly journals Joining thin-walled structures without protuberance by two-strokes flattening clinching process

2021 ◽  
Author(s):  
Hao Peng ◽  
Chao Chen ◽  
Haijun Li ◽  
Xiaolei Gao
Keyword(s):  
Energy Absorption ◽  
Failure Mode ◽  
Material Flow ◽  
Failure Modes ◽  
Mechanical Response ◽  
Flow Analysis ◽  
Material Flow Analysis ◽  
Mechanical Behaviors ◽  
Thin Walled Structures ◽  
Static Conditions

Abstract Clinching technologies have better performance in joining different sheet materials. However, the protuberance and mechanical behaviors of clinched joints have always been needed to be improved. In this paper, a new clinching method, named two-strokes flattening clinching (TFC) process, was proposed to improve the mechanical behaviors of joints and flatten the protuberance. Mechanical testing including tension shearing tests were employed under quasi-static conditions to evaluate the different mechanical behaviors between TFC and conventional clinched joints. The influences of the different forming forces on mechanical response of these joints were studied. The static strength, energy absorption, material flow and failure modes of TFC and conventional clinched joints were investigated comparatively. The experimental results demonstrated that the tension-shear strength of TFC clinched joints was increased by 30.3% compared with conventional clinched joints at the forming force of 30 kN. Furthermore, the material flow analysis showed that the thickness and interlock of TFC clinched joints were increased by 79% and 45.9%, respectively. The energy absorption of TFC clinched joint was increased by 82%. In addition, the TFC process did not change the failure mode of clinched joints, and the failure mode of all clinched joints was neck fracture.

Effect of interlayer hybridization of carbon, Kevlar, and glass fibers with oxidized polyacrylonitrile fibers on the mechanical behaviors of hybrid composites

2019 ◽  
Vol 234 (9) ◽  
pp. 1823-1835 ◽  
Author(s):  
Hossein Ebrahimnezhad-Khaljiri ◽  
Reza Eslami-Farsani ◽  
Ebrahim Akbarzadeh
Keyword(s):  
Energy Absorption ◽  
Carbon Fibers ◽  
High Performance ◽  
Hybrid Composites ◽  
Glass Fibers ◽  
Mechanical Tests ◽  
Epoxy Composites ◽  
Polyacrylonitrile Fiber ◽  
Flexural Test ◽  
Mechanical Behaviors

This study focuses on tensile and flexural behaviors of epoxy composites, which have been reinforced by oxidized polyacrylonitrile fibers and high-performance fibers (carbon, glass, and Kevlar). In hybrid composites, the parameters of hybridization show positive or negative hybrid effects on its mechanical properties. The results of energy absorption achieved from the tensile test depicted that reinforced hybrid composites by two plies of oxidized polyacrylonitrile fiber and two plies of carbon, Kevlar, and glass fibers with energy absorption of 916, 700, and 899 kJ m–3 had the maximum hybridization parameter, which were 1.1, 0.64, and 1.54, respectively. Also, the mentioned hybrid composites with flexural stresses of 279.4, 198.5, and 167.3 MPa had the maximum hybridization parameter in a flexural test, which were 3.01, 2.68, and 1.80, respectively. Hybrid composites, which were reinforced by three plies of oxidized polyacrylonitrile fiber/one ply carbon fibers, three plies of oxidized polyacrylonitrile fiber/one ply of glass fibers, and two plies of oxidized polyacrylonitrile fiber/two plies of Kevlar fibers, had the maximum pseudo strain in their group, which were 0.12%, 0.65%, and 0.17%, respectively. The microstructure investigations depicted crossing cracks among oxidized polyacrylonitrile fiber and cutting the oxidized polyacrylonitrile fiber, which were caused to increase the hybridization parameters in mechanical tests. Also, it was found that as compared with carbon, glass, and Kevlar fibers, oxidized polyacrylonitrile fiber had a ductile fracture, which was the reason for the pseudo-ductility behavior in hybrid composites.

scholarly journals Uniaxial compressive strength and failure characteristics of arkosic sandstone after thermal treatment

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2991-3000
Author(s):  
Yuan Zhang ◽  
Yangsheng Ma ◽  
Bin Gu ◽  
Xupeng Ta ◽  
Qun Wang
Keyword(s):  
Mechanical Properties ◽  
Mutual Influence ◽  
Deformation Modulus ◽  
Dominant Factor ◽  
Peak Strain ◽  
Thermal Fracture ◽  
Mechanical Behaviors ◽  
Variation Trend ◽  
Mineral Particles ◽  
Temperature Ranges

Experiments were conducted to study the mechanical characteristics of arkosic sandstones sampled from Pingyi, China. Rock samples were all thermally treated under the temperature ranging from room temperature to 800?C. Results show that as the treatment temperature rises, the arkosic mineral composition does not change obviously, but the mechanical behaviors change regularly. Variation trend changes dramatically at 200?C, 400?C, and 500?C. With thermal expan?sion of mineral particles being the dominant factor, mechanical behaviors barely change below 200?C. When temperature ranges from 200-400?C, it has an important effect on the mechanical properties because of the thermal fracture. From 400-500?C, mechanical properties change dramatically as a result of the mutual influence of thermal fracture, fusion and re-crystallization, but the thermal fracture is the leading factor. Because of the fusion and re-crystallization, fractures are partly filled, which results in partial recovering of the mechanical strength. With the combined action of thermal fracture, fusion and re-crystallization after 600?C, mechanical performance of arkosic sandstones degrades rapidly. Generally, the porosity and peak strain of arkosic sandstones increase with the temperature rising. However, the peak stress, elastic modulus and deformation modulus decrease simultaneously. Influenced by mineral particles? thermal expansion, thermal fracture, fusion, and re-crystallization and so on, the variation trend and amplitude are not the same at different temperature ranges, and the damage mechanism of sandstones also makes a difference.

scholarly journals Effect of uniaxial stress on bursting energy absorption of paper

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7249-7262
Author(s):  
Konrad Olejnik ◽  
Anna Stanisławska ◽  
Jean-Francis Bloch
Keyword(s):  
Energy Absorption ◽  
Uniaxial Stress ◽  
Accurate Method ◽  
Strength Properties ◽  
Experimental Setup ◽  
Paper Strength ◽  
Mechanical Behaviors ◽  
Regression Curve ◽  
Bursting Strength ◽  
Linear Regression Curve

The overall usefulness of the bursting energy absorption (BEA) was studied for a better analysis of paper strength properties. Additionally, the changes of the BEA during more complex deformations of paper products, e.g., preliminary or simultaneous tensile and burst, were determined. For the purpose of the research, an experimental setup was designed. The results showed that the correlation between BEA and bursting strength was linear, but the proportionality strongly depended on paper grade. Thus, a more accurate method to characterize the bursting resistance (BR) of paper was proposed. The BR parameter is described by the three following parameters: average bursting strength, average bursting energy absorption, and the slope of the fitted linear regression curve (relationship between the bursting energy absorption and the bursting strength). This method revealed new mechanical behaviors of papers related to their preloading.

Optical and Electrical Properties of Organic Conducting Polymers

2014 ◽  
Vol 8 (1) ◽  
pp. 1457-1463
Author(s):  
Salah Abdulla Hasoon
Keyword(s):  
Electrical Properties ◽  
Conjugated Polymer ◽  
Polymeric Materials ◽  
Quantum Mechanical ◽  
Optical And Electrical Properties ◽  
Electrically Conducting ◽  
Temperature Ranges ◽  
Lithium Tetrafluoroborate ◽  
Absorbance Peak ◽  
Polymerization Method

Novel electrically conducting polymeric materials are prepared in this work. Polythiophene (PT) and poly (3-Methelthiophene) (P3MT) films were prepared by electro-polymerization method using cyclic voltammetry in acetonitrile as a solvent and lithium tetrafluoroborate as the electrolyte on a gold electrode. Electrical properties of P3MT have been examined in different environments using UV-Vis absorption spectroscopy and quantum mechanical ab initio calculations, The observed absorption peaks at 314 and 415 nm, were attributed to the n-π* and π-π* transitions, respectively in the conjugated polymer chain, in contrast, the observed absorbance peak at 649 nm, is responsible for electric conduction. The temperature dependence of the conductivity can be fitted to the Arrhenius and the VTF equations in different temperature ranges.

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