Coupled Electromechanical Peristatic Simulation of Deformation and Damage Sensing in Granular Materials

2016 ◽  
Author(s):  
Naveen Prakash ◽  
Gary D. Seidel
Keyword(s):  
Energetic Materials ◽  
Imaging Techniques ◽  
Low Velocity Impact ◽  
Polymer Phase ◽  
Explosive Material ◽  
Low Velocity ◽  
Computational Framework ◽  
Damage Sensing ◽  
Explosive Materials ◽  
Microstructure Of The Material

Energetic materials or explosives are a class of granular composite materials consisting of explosive grains dispersed in a polymer matrix. An accidental low velocity impact during transportation may cause damage in the material, which may lead to weakening and possibly ignition of the material. Traditional SHM methods such external sensors or imaging techniques may not reveal changes in the internal microstructure of the material. It is proposed that dispersing carbon nanotubes in the polymer phase of the explosive material will introduce piezoresistivity by which the health of the material can be monitored in real time. In this work, a coupled electromechanical computational framework is developed to investigate nanocomposites and applied to model deformation and damage sensing in nanocomposite bonded explosive materials.

scholarly journals Improvement of Composite Propellants Energy Using Explosive Materials

2021 ◽  
Author(s):  
Amjad O. Saeed ◽  
Nagmeldin M. Elamin
Keyword(s):  
Chemical Reactions ◽  
Energetic Materials ◽  
High Pressures ◽  
Specific Impulse ◽  
Significant Positive Effect ◽  
Explosive Material ◽  
Composite Propellant ◽  
Explosive Materials ◽  
High Pressures And Temperatures ◽  
Positive Effect

Composite propellants are energetic materials have ability to ignite, burn fast and cause several simultaneous exothermic chemical reactions which produce huge amounts of gases under high pressures and temperatures which can spread spontaneously. 1n the present study, the explosive material hexogen (Cyclo tri-methylene tri-nitramine) was used to improve the performance properties of composite propellants, especially the specific impulse. For several formulations of hexogen at different added percentages, the specific impulse was calculated using thermodynamic calculations program of composite propellants. The results given were compared with those formulations not including hexogen. It was seen that; hexogen caused a significant positive effect in the specific impulse. Accordingly, the energy of composite propellant was improved positively in the samples containing hexogen till 40% of the oxidizer ratio. Also, it was noticed that the specific impulse began to decrease gradually for the oxidizers containing more than 40% of hexogen which caused in a decreasing of composite propellant energy. Finally, it was concluded that, the use of some amount of explosive materials like hexogen can improve composite propellants energy successfully.

Predictions of Localised Damage to Concrete Caused by a Low-Velocity Impact

2021 ◽  
Vol 149 ◽  
pp. 103799
Author(s):  
Zireen Z.A. Majeed ◽  
Nelson T.K. Lam ◽  
Emad F. Gad
Keyword(s):  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact

Dynamic compressive response of 3D GFRP composites with shear thickening fluid (STF) matrix as cushioning materials

2021 ◽  
pp. 002199832098424
Author(s):  
Mohsen Jeddi ◽  
Mojtaba Yazdani
Keyword(s):  
Shear Thickening ◽  
Low Velocity Impact ◽  
Gfrp Composites ◽  
High Concentration ◽  
Low Velocity ◽  
Shear Thickening Fluid ◽  
Compressive Response ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Shear Thickening Fluids

Whereas most previous studies have focused on improving the penetration resistance of Shear Thickening Fluids (STFs) treated composites, in this study, the dynamic compressive response of single and multi-ply 3 D E-Glass Fiber Reinforced Polymer (GFRP) composites with the STF matrix was investigated by using a drop-weight low-velocity impact test. The experimental results revealed the STF improved the compressive and cushioning performance of the composites such that with increasing its concentration, further improvement was observed. The five-ply composite containing the STF of 30 wt% silica nanoparticles and 1 wt% carbon nanotubes (CNTs) reduced the applied peak force by 56% and 26% compared to a steel plate and five-ply neat samples, respectively. A series of repeated impacts was performed, and it was found that the performance of high-concentration composites is further decreased under this type of loading.

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