Acoustic energy absorption in Ni–Mn–Ga/polymer composites

2011 ◽  
Vol 323 (8) ◽  
pp. 1098-1100 ◽  
Author(s):  
Manickam Mahendran ◽  
Jorge Feuchtwanger ◽  
Ratchatee Techapiesancharoenkij ◽  
David Bono ◽  
Robert C. O’Handley
2021 ◽  
Vol 5 (8) ◽  
pp. 201
Author(s):  
Fabio C. Garcia Filho ◽  
Fernanda S. Luz ◽  
Michelle S. Oliveira ◽  
Wendell B. A. Bezerra ◽  
Josiane D. V. Barbosa ◽  
...  

Since the mid-2000s, several studies were carried out regarding the development of ballistic resistant materials based on polymeric matrix composites reinforced with natural lignocellulosic fibers (NLFs). The results reported so far are promising and are often comparable to commonly used materials such as KevlarTM, especially when used as an intermediate layer in a multilayer armor system (MAS). However, the most suitable configuration for these polymer composites reinforced with NLFs when subjected to high strain rates still lacks investigation. This work aimed to evaluate four possible arrangements for epoxy matrix composite reinforced with a stiff Brazilian NLF, piassava fiber, regarding energy absorption, and ballistic efficiency. Performance was evaluated against the ballistic impact of high-energy 7.62 mm ammunition. Obtained results were statistically validated by means of analysis of variance (ANOVA) and Tukey’s honest test. Furthermore, the micromechanics associated with the failure of these composites were determined. Energy absorption of the same magnitude as KevlarTM and indentation depth below the limit predicted by NIJ standard were obtained for all conditions.


2002 ◽  
Vol 36 (7) ◽  
pp. 813-850 ◽  
Author(s):  
George C. Jacob ◽  
John F. Fellers ◽  
Srdan Simunovic ◽  
J. Michael Starbuck

Author(s):  
Qihang Liu ◽  
Xuewei Liu ◽  
Chuanzeng Zhang ◽  
Fengxian Xin

AbstractIn this paper, we propose a novel porous metamaterial structure with an improved acoustic energy absorption performance at high-temperature and in the low-frequency range. In the proposed novel porous metamaterial structure, a porous material matrix containing periodically perforated cylindrical holes arranged in a triangular lattice pattern is applied, and additional interlayers of another porous material are introduced around these perforations. The theoretical model is established by adopting the double porosity theory for the interlayer and the cylindrical hole which form an equivalent inclusion and then applying the homogenization method to the porous metamaterial structure formed by the equivalent inclusion and the porous matrix. The temperature-dependent air and material parameters are considered in the extended theoretical model, which is validated by the finite element results obtained by COMSOL Multiphysics. The acoustic or sound energy absorption performance can be improved remarkably at very low frequencies and high temperature. Furthermore, the underlying acoustic energy absorption mechanism inside the unit-cell is investigated by analyzing the distribution of the time-averaged acoustic power dissipation density and the energy dissipation ratio of each constituent porous material. The results reveal that regardless of the temperature, the acoustic energy is mostly dissipated in the porous material with a lower airflow resistivity, while the acoustic energy dissipated in the porous material with a higher airflow resistivity also becomes considerable in the high-frequency range. The novel porous metamaterial structure proposed in this paper can be efficiently utilized to improve the acoustic energy absorption performance at high temperature.


2003 ◽  
Vol 93 (10) ◽  
pp. 8528-8530 ◽  
Author(s):  
Jorge Feuchtwanger ◽  
Sadie Michael ◽  
Jiankang Juang ◽  
David Bono ◽  
Robert C. O’Handley ◽  
...  

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