A semi‐analytical framework for time history response of a carbon nanotube ‐reinforced polymer damped composite plate: Influence of instability regions

2021 ◽  
Author(s):  
Vishal Singh ◽  
Rajesh Kumar
Keyword(s):  
Carbon Nanotube ◽  
Composite Plate ◽  
Time History ◽  
Analytical Framework ◽  
Reinforced Polymer ◽  
Time History Response ◽  
Instability Regions

Buckling and Free Vibration of Nonuniformly Heated Functionally Graded Carbon Nanotube Reinforced Polymer Composite Plate

2017 ◽  
Vol 17 (06) ◽  
pp. 1750064 ◽  
Author(s):  
Nivish George ◽  
P. Jeyaraj ◽  
S. M. Murigendrappa
Keyword(s):  
Temperature Field ◽  
Carbon Nanotube ◽  
Free Vibration ◽  
Composite Plate ◽  
Natural Frequencies ◽  
Vibration Mode ◽  
Functionally Graded ◽  
Temperature Fields ◽  
Mode Shapes ◽  
Reinforced Polymer

Buckling and free vibration behavior of functionally graded carbon nanotube reinforced polymer composite plate subjected to nonuniform temperature fields have been investigated using finite element approach. The effective material constants of the plate are obtained using the extended rule of mixture along with efficiency parameters of the carbon nanotube (to include geometry-dependent material properties). Influence of boundary conditions, aspect ratio, functional grading of the carbon nanotube, nonuniform thermal loading on thermal buckling and free vibration behavior of the heated plate are analyzed. It is observed that temperature fields and functional grading are influenced on the critical buckling temperature of the plates. Further, nature of functional grading showed significant change in buckling mode shapes irrespective of the boundary conditions. The first few natural frequencies of the plate under thermal load decreases as the temperature increases and they are influenced significantly by the nature of temperature field. Variations in free vibration mode shapes of the square plates found with not significant change as temperature increases. However, free vibration modes of the rectangular plates are sensitive to the nature of temperature field whenever there is a free edge associated with the boundary condition. Influence of functional grading on the free vibration mode shapes is not significant in contrast with the free vibration natural frequencies. The magnitude of free vibration natural frequencies of functional grade-X type carbon nanotube reinforcement showed higher in comparison with other two types of reinforcements considered here.

A statistical study on artificially generated earthquake records

1976 ◽  
Vol 3 (1) ◽  
pp. 11-19
Author(s):  
W. K. Tso ◽  
B. P. Guru
Keyword(s):  
Statistical Study ◽  
Spectral Response ◽  
Flexible Structures ◽  
Time History ◽  
Maximum Response ◽  
Response Analysis ◽  
Seismic Region ◽  
Natural Period ◽  
Earthquake Records ◽  
Time History Response

A statistical study has been done to investigate (i) the variation of spectral responses of structures due to artificially generated earthquake records with identical statistical properties, (ii) the effect of duration of strong shaking phase of artificial earthquakes on the response of structures, and (iii) the number of earthquake records needed for time-history response analysis of a structure in a seismic region. The results indicate that the flexible structures are more sensitive to the inherent statistical variations among statistically identical earthquake records. Consequently several records must be used for time-history response analysis. A sample of eight or more records appear to provide a good estimate of mean maximum response. The duration of strong shaking can significantly affect the maximum response. Based on the results, it is suggested that for the purpose of estimating peak response, the strong shaking duration of the input earthquake motion should be at least four times the natural period of the structure. The maximum responses due to statistically identical ground motion records are observed to fit approximately the type 1 extreme value distribution. Thus, it is rationally possible to choose a design value based on the mean, standard deviation of the spectral response values and tolerable probability of exceedance.

Dynamic Instability of Delaminated Composite Plates under Parametric Excitation

2006 ◽  
Vol 326-328 ◽  
pp. 1765-1768 ◽  
Author(s):  
Meng Kao Yeh ◽  
Kuei Chang Tung
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parametric Excitation ◽  
Composite Plate ◽  
Dynamic Instability ◽  
Composite Plates ◽  
Modal Parameters ◽  
The Finite Element Method ◽  
Electromagnetic Device ◽  
Instability Regions

The dynamic instability behavior of delaminated composite plates under transverse excitations was investigated experimentally and analytically. An electromagnetic device, acting like a spring with alternating stiffness, was used to parametrically excite the delaminated composite plates transversely. An analytical method, combined with the finite element method, was used to determine the instability regions of the delaminated composite plates based on the modal parameters of the composite plate and the position, the stiffness of the electromagnetic device. The delamination size and position of composite plates were varied to assess their effects on the excitation frequencies of simple and combination resonances in instability regions. The experimental results were found to agree with the analytical ones.

Settlement Analysis of Soft Ground Replacement under Earthquake

2012 ◽  
Vol 166-169 ◽  
pp. 2379-2382 ◽  
Author(s):  
Zhong Liu ◽  
Shu Hong An ◽  
Rong Hong Yuan ◽  
Fei Li
Keyword(s):  
Time History ◽  
Vertical Displacement ◽  
Response Analysis ◽  
Soft Ground ◽  
Positive Contribution ◽  
Foundation Soil ◽  
Time History Response ◽  
Dynamic Time ◽  
Settlement Analysis ◽  
Different Thickness

The dynamic time-history response analysis method was employed to analyze the dynamic response of soft ground replacement with sand-gravel cushion. The deformation distribution of soft ground replacement with different thickness sand-gravel cushion was investigated under seismic wave. The results reveal that the bearing and asti-deformation capacity can be improved effectively for replacement sand-gravel cushion under earthquake loads by increasing the thick of cushion. The vertical displacement of foundation soil decreases gradually with the increase of the thick of cushion. The practice shows that replacement sand-gravel cushion provides a positive contribution to the aseismic effect of foundation soils mass. The present research can provide some references to similar projects.

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