The Mechanical Response of Virgin and Aged RDX/CL20/BAMO/AMMO-Based High-Energy Gun Propellants

2001 ◽  
Author(s):  
Michael G. Leadore
Keyword(s):  
Mechanical Response ◽  
High Energy ◽  
Gun Propellants

scholarly journals Research on the Response Characteristics of Bio-Inspired Composite Sandwich Structure under Low Velocity Impact

2021 ◽  
Vol 2101 (1) ◽  
pp. 012087
Author(s):  
Peng Hao ◽  
Lin’an Li ◽  
Jianxun Du
Keyword(s):  
Sandwich Structure ◽  
Mechanical Response ◽  
Shear Fracture ◽  
Impact Load ◽  
High Energy ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Response Characteristics ◽  
Composite Sandwich ◽  
The Impact

Abstract In order to research the impact mechanical response characteristics of the bio-inspired composite sandwich structure, the hemispherical impactor is preloaded with different energy to impact bio-inspired and conventional composite sandwich structure, the stress distribution and dynamic response characteristics of composite sandwich structure under impact load are studied. The results show that the main damage of the upper panel is fiber shear fracture, while crushing fracture for the core, and the main damage of the lower panel is fiber tensile tearing under different impact load. The bio-inspired composite sandwich structure shows better impact resistance in terms of damage depth and maximum impact load under the same impact energy. From the perspective of energy consumption, the bio-inspired structure absorbed more energy than conventional structure under high energy impact.

scholarly journals Numerical Study of Rock Fragmentation Process and Acoustic Emission by FDEM Based on Heterogeneous Model

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qi Liu ◽  
Penghai Deng
Keyword(s):  
Acoustic Emission ◽  
Mechanical Response ◽  
Numerical Study ◽  
High Energy ◽  
Uniaxial Compression Test ◽  
Rock Damage ◽  
Heterogeneous Model ◽  
Damage And Fracture ◽  
Heterogeneous Rock ◽  
Rock Model

Rock has the characteristics of natural heterogeneity and discontinuity. Its failure phenomenon induced by external force involves complex processes, including the microcrack initiation, propagation, coalescence, and the macrocrack formation. In this study, the Weibull random distribution based on the rock microstructure characteristics is introduced into the combined finite-discrete element method (FDEM) to establish the heterogeneous rock model, and the mechanical response and damage evolution of rock samples in uniaxial compression test are simulated. The results show that FDEM simulation with loaded heterogeneous rock model can reflect the progressive development of rock damage, fracture, and acoustic emission (AE) activity in real rock well. Meanwhile, the statistical analysis indicates that the number and energy evolution of AE events with different fracture modes in the model are consistent with the macroscopic failure mode of rock. The change of b-value also agrees with the increasing trend of high-energy events in the loading process. This method provides a new tool for the analysis of rock damage and fracture evolution.

scholarly journals Improvement of Mechanical Properties of Plasma Sprayed Al2O3-ZrO2-SiO2 Amorphous Coatings by Surface Crystallization

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3232 ◽  
Author(s):  
Jan Medricky ◽  
Frantisek Lukac ◽  
Stefan Csaki ◽  
Sarka Houdkova ◽  
Maria Barbosa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Large Scale ◽  
Mechanical Response ◽  
High Energy ◽  
Hardness Profile ◽  
Treatment Conditions ◽  
Content Ratio ◽  
Plasma Sprayed

Ceramic Al2O3-ZrO2-SiO2 coatings with near eutectic composition were plasma sprayed using hybrid water stabilized plasma torch (WSP-H). The as-sprayed coatings possessed fully amorphous microstructure which can be transformed to nanocrystalline by further heat treatment. The amorphous/crystalline content ratio and the crystallite sizes can be controlled by a specific choice of heat treatment conditions, subsequently leading to significant changes in the microstructure and mechanical properties of the coatings, such as hardness or wear resistance. In this study, two advanced methods of surface heat treatment were realized by plasma jet or by high energy laser heating. As opposed to the traditional furnace treatments, inducing homogeneous changes throughout the material, both approaches lead to a formation of gradient microstructure within the coatings; from dominantly amorphous at the substrate–coating interface vicinity to fully nanocrystalline near its surface. The processes can also be applied for large-scale applications and do not induce detrimental changes to the underlying substrate materials. The respective mechanical response was evaluated by measuring coating hardness profile and wear resistance. For some of the heat treatment conditions, an increase in the coating microhardness by factor up to 1.8 was observed, as well as improvement of wear resistance behaviour up to 6.5 times. The phase composition changes were analysed by X-ray diffraction and the microstructure was investigated by scanning electron microscopy.

scholarly journals Tying Processing Parameters to the Microstructure and Mechanical Properties of Nanostructured FeNiZr Consolidated via the Field Assisted Sintering Technique

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 436
Author(s):  
Sean J. Fudger ◽  
Thomas L. Luckenbaugh ◽  
Anthony J. Roberts ◽  
Chris D. Haines ◽  
Kris A. Darling
Keyword(s):  
Mechanical Response ◽  
Hold Time ◽  
Oxide Dispersion Strengthened ◽  
Processing Parameters ◽  
High Energy ◽  
Microstructural Coarsening ◽  
The Cost ◽  
Field Assisted Sintering ◽  
Hardness Values ◽  
Consolidation Temperature

An oxide-dispersion-strengthened (ODS) nanostructured FeNiZr alloy was fabricated via high energy mechanical alloying, and subsequently consolidated by the field assisted sintering technique (FAST). A range of input parameters: Temperature, hold time and pressure were evaluated in an effort to optimize the mechanical response of the material. Improvements in density, up to 98.6% of theoretical, were observed with increasing consolidation temperature and hold time at the cost of decreasing hardness values resulting from microstructural coarsening. Hardness values decreased from 650 to 275 HV by increasing processing temperatures from 750 to 1100 °C. The relationships between the varied processing parameters, microstructure and the experimentally measured yield and ultimate tensile strengths are discussed. Specifically, the effect of varying the temperature and hold time on the resulting porosity, as observed via scanning electron microscopy (SEM) in tensile and compression samples, is emphasized.

scholarly journals An experimental investigation of the response of slender protective structures to rockfall impacts

2020 ◽  
Vol 57 (8) ◽  
pp. 1215-1231 ◽  
Author(s):  
Stéphane Lambert ◽  
Frank Bourrier ◽  
Philippe Gotteland ◽  
François Nicot
Keyword(s):  
Mechanical Response ◽  
Lateral Diffusion ◽  
Middle Layer ◽  
High Energy ◽  
Wire Mesh ◽  
Fill Material ◽  
Measuring Techniques ◽  
Protective Structures ◽  
Impact Energies ◽  
Real Scale

This article investigates the mechanical response of slender rockfall protection embankments subjected to impacts based on real-scale experiments. More specifically, it deals with rectangular (in cross-section) vertical-sided gabion structures, designed to meet footprint constraints. These three-layered structures, 3 m in width and 4 m in height, are made up of gabion cages filled with different materials, depending on their location in the structure. Real-scale experiments were conducted with impact energies up to about 2000 kJ on two structures differing by the fill material used for their middle layer: ballast or sand–tire mixture. The experiments demonstrate the capacity of these slender structures in resisting high-energy impacts. The response of the structures is also addressed considering data obtained using different measuring techniques and a large number of sensors within the structure. The results are presented and discussed with the aim of highlighting some issues associated with the structure impact response, such as the load lateral diffusion, stone breakage, the contribution of the wire mesh, and the fill material characteristics. In the end, a structure with a middle layer filled with ballast appears more efficient in reducing the structure back face displacement.

Mechanical and Microstructural Investigation of the Cyclic Behavior of Human Amnion

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Michela Perrini ◽  
Arabella Mauri ◽  
Alexander Edmund Ehret ◽  
Nicole Ochsenbein-Kölble ◽  
Roland Zimmermann ◽  
...  
Keyword(s):  
Mechanical Response ◽  
High Energy ◽  
Cyclic Behavior ◽  
Fetal Membrane ◽  
Repeated Loading ◽  
Microstructural Investigation ◽  
Human Amnion ◽  
Fiber Reorientation ◽  
In Situ Experiments

The structural and mechanical integrity of amnion is essential to prevent preterm premature rupture (PPROM) of the fetal membrane. In this study, the mechanical response of human amnion to repeated loading and the microstructural mechanisms determining its behavior were investigated. Inflation and uniaxial cyclic tests were combined with corresponding in situ experiments in a multiphoton microscope (MPM). Fresh unfixed amnion was imaged during loading and changes in thickness and collagen orientation were quantified. Mechanical and in situ experiments revealed differences between the investigated configurations in the deformation and microstructural mechanisms. Repeated inflation induces a significant but reversible volume change and is characterized by high energy dissipation. Under uniaxial tension, volume reduction is associated with low energy, unrecoverable in-plane fiber reorientation.

scholarly journals Biopolymers and its application as electroactive polymers

2021 ◽  
Vol 83 (1) ◽  
pp. 270-277
Author(s):  
Rigel Antonio Olvera Bernal ◽  
M. V. Uspenskaya ◽  
R. O. Olekhnovich
Keyword(s):  
Smart Materials ◽  
Mechanical Response ◽  
Low Cost ◽  
Electroactive Polymers ◽  
Fast Response ◽  
High Energy ◽  
High Energy Density ◽  
Compact Size ◽  
Wide Range ◽  
Electrical Stimuli

Smart materials are a group of materials that exhibit the ability to change their composition or structure, their electrical and/or mechanical properties, or even their functions in response to an external stimulus such as heat, light, electricity, pressure, etc. Some of the advantages of these materials are: lightweight, flexibility, low cost of production, high energy density, fast response and compact size. One of the promises in the area of smart materials can be found in “smart polymer”. Polymers have many attractive characteristics, such as: lightweight, inexpensiveness, fractures tolerant, and pliable. Furthermore, they can be configured into almost any conceivable shape and their properties can be tailored according to the required needs. The capability of electroactive polymers (EAPs) to respond to electrical stimuli with a mechanical response, is attracting the attention of the scientific community from a wide range of disciplines. Biopolymers in recent decades have been studied as potential electroactive materials. These groups of polymers are extracted from a natural source; thus, they are eco-friendly, additionally they stand as a cheaper solution for the development of smart materials.The present manuscript will explore some of its applications as EAPs.

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