Geometrically nonlinear static and dynamic analysis of CNT reinforced laminated composite plates: A finite element study

Author(s):  
Balakrishna Adhikari ◽  
BN Singh

In this paper, a finite element study is conducted using the Green Lagrange strain field based on vonKarman assumptions for the geometric nonlinear static and dynamic response of the laminated functionally graded CNT reinforced (FG-CNTRC) composite plate. The governing equations for determining the nonlinear static and dynamic behavior of the FG-CNTRC plate are derived using the Lagrange equation of motion based on Reddy's higher order theory. Using the direct iteration technique, the nonlinear eigenvalues for analyzing the free vibration response are obtained and the nonlinear dynamic responses of the FG-CNTRC plate are encapsulated based on the nonlinear Newmark integration scheme. The impact of the amplitude of vibration on mode switching phenomena and the consequence of the duration of the pulse on the free vibration regime of the plate are outlined. Also, the effect of time dependent loads is studied on the normal stresses of the plate. Furthermore, the impact on the nonlinear static and dynamic response of the laminated FG-CNTRC plate of various parameters such as span-thickness ratio (b/h ratio), aspect ratio (a/b ratio), different edge constraints, CNT fiber gradation, etc. are also studied.

Author(s):  
John Hutchinson ◽  
Keith Friedman

The Jordan Rollover System (JRS) is a physical test apparatus which evaluates vehicle rollover protection performance by dropping a rotating vehicle with a stationary CG position onto a moving road bed. This test configuration permits control and monitoring of the rollover test conditions, and allows the rollover test to be conducted in a limited space. A finite element study was conducted to determine how well the JRS test replicates the impact environment of an equivalent over-the-ground rollover event. In particular, the effects of the finite mass of the test roadbed and the test apparatus constraints were examined. The finite element study showed that roof intrusion measures occurring during the JRS test do not vary significantly from those resulting from an unrestrained over-the-ground rollover impact with the same initial conditions.


Author(s):  
Ali Merdji ◽  
Belaid Taharou ◽  
Rajshree Hillstrom ◽  
Ali Benaissa ◽  
Sandipan Roy ◽  
...  

2020 ◽  
Vol 10 (14) ◽  
pp. 4737
Author(s):  
Chao Xu ◽  
Suli Pan

The coefficient of consolidation is traditionally considered as a constant value in soil consolidation calculations. This paper uses compression and recompression indexes to calculate the solution-dependent nonlinear compressibility, thus overconsolidation and normal consolidation are separated during the calculations. Moreover, the complex nonlinear consolidation can be described using the nonlinear compressibility and a nonlinear permeability. Then, the finite element discrete equation with consideration of the time-dependent load is derived, and a corresponding program is developed. Subsequently, a case history is conducted for verifying the proposed method and the program. The results show that the method is sufficiently accurate, indicating the necessity of considering nonlinearity for consolidation calculations. Finally, three cases are compared to reveal the importance of separating the overconsolidation and normal consolidation. Overall, this study concluded that it is inadequate to consider just one consolidation status in calculations, and that the proposed method is more reasonable for guiding construction.


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