Hygrothermal Effects on Dynamic Instability of Hybrid Composite Plates

2017 ◽  
Vol 17 (01) ◽  
pp. 1750001 ◽  
Author(s):  
Chun-Sheng Chen ◽  
An-Hung Tan ◽  
Jin-Yih Kao ◽  
Wei-Ren Chen
Keyword(s):  
Layer Thickness ◽  
Hybrid Composite ◽  
Volume Fraction ◽  
Dynamic Instability ◽  
Composite Plates ◽  
Thickness Ratio ◽  
Fiber Volume ◽  
Periodic Load ◽  
Moisture Concentration ◽  
Layer Thickness Ratio

The dynamic characteristics of hybrid composite plates under an arbitrary periodic load in hygrothermal environments are investigated. The material properties of the plate are assumed to be dependent on the temperature and moisture. The governing equations of motion of the Mathieu-type are established based on the Galerkin method with reduced eigenfunction transforms. The periodic stress is taken to be a combination of the pulsating axial and bending stress in the example problems. Based on Bolotin’s method, the dynamic instability behaviors of hybrid composite plates are determined. The effects of layer thickness ratio, fiber volume fraction, temperature rise, moisture concentration and dynamic load on the instability regions of hybrid composite plates are studied, along with the dynamic instability index discussed. The results reveal that the layer thickness ratio and hygrothermal conditions have a significant impact on the dynamic instability of hybrid composite plates.

DYNAMIC STABILITY CHARACTERISTICS OF FUNCTIONALLY GRADED PLATES UNDER ARBITRARY PERIODIC LOADS

2013 ◽  
Vol 13 (06) ◽  
pp. 1350026 ◽  
Author(s):  
CHUN-SHENG CHEN ◽  
CHIH-WEN CHEN ◽  
WEI-REN CHEN
Keyword(s):  
Layer Thickness ◽  
Dynamic Load ◽  
Volume Fraction ◽  
Dynamic Instability ◽  
Plate Thickness ◽  
Excitation Frequency ◽  
Frequency Instability ◽  
Functionally Graded ◽  
Functionally Graded Plates ◽  
Periodic Load

The dynamic instability of functionally graded material (FGM) plates under an arbitrary periodic load is studied. The properties of the functionally graded plates (FGPs) are assumed to vary continuously across the plate thickness according to a simple power law. With the derived Mathieu equations, the dynamic instability regions of the FGPs are determined by using the Bolotin's method. The in-plane periodic load is taken to be a combination of periodic axial and bending stress in the example problems. The influences of the volume fraction index, layer thickness ratio, static and dynamic load on the dynamic instability of ceramic-FGM-metal plates are discussed. The results reveal that the excitation frequency, instability region and dynamic instability index of these plates are significantly affected by the static load, dynamic load, volume fraction index and layer thickness.

Tuning Negative Capacitance in PbZr0.2Ti0.8O3/SrTiO3 Heterostructures via Layer Thickness Ratio

2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Yifei Hao ◽  
Tianlin Li ◽  
Yu Yun ◽  
Xin Li ◽  
Xuegang Chen ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Thickness Ratio ◽  
Negative Capacitance ◽  
Layer Thickness Ratio

Bending, free vibration, and buckling responses of chopped carbon fiber/graphene nanoplatelet-reinforced polymer hybrid composite plates: An inclusive microstructural assessment

2020 ◽  
pp. 095440622094278
Author(s):  
A Bakamal ◽  
R Ansari ◽  
MK Hassanzadeh-Aghdam
Keyword(s):  
Carbon Fiber ◽  
Free Vibration ◽  
Carbon Fibers ◽  
Hybrid Composite ◽  
Composite Structures ◽  
Volume Fraction ◽  
Composite Plates ◽  
Graphene Nanoplatelet ◽  
Polymer Hybrid ◽  
Reinforced Polymer

This paper presents a finite element analysis of the bending, buckling, and free vibration of the chopped carbon fiber/graphene nanoplatelet reinforced polymer hybrid composite plates. Both rectangular and circular composite plates are considered. The effective material properties of the chopped carbon fiber /graphene nanoplatelet reinforced hybrid composites are predicted using a multistep micromechanical model based on the Halpin–Tsai homogenization scheme. An inclusive microstructural assessment is accomplished by the evaluation of the influences of the volume fraction, length, thickness, and agglomeration of graphene nanoplatelets as well as the volume fraction, aspect ratio, and the alignment of the chopped carbon fibers on the mechanical behaviors of the chopped carbon fiber/graphene nanoplatelet hybrid composite plates. It is found that the bending, buckling, and vibration characteristics of hybrid composite structures are highly affected by the microstructural features. The addition of graphene nanoplatelets improves the stability of the chopped fiber-reinforced hybrid composite structures. The agglomeration of the graphene nanoplatelet into the polymer matrix leads to a degradation in the composite plate mechanical performances. Aligning the chopped carbon fibers significantly decreases the deflections, and increases the critical buckling loads and the natural frequencies of hybrid composite plates. Comparisons are conducted with the numerical results reported in literature that indicate good agreement with our results.

The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel

2018 ◽  
Author(s):  
Emre Özaslan ◽  
Ali Yetgin ◽  
Volkan Coşkun ◽  
Bülent Acar ◽  
Tarık Olğar
Keyword(s):  
Finite Element ◽  
Layer Thickness ◽  
Pressure Vessel ◽  
Fiber Volume Fraction ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Element Model ◽  
Layer By Layer ◽  
Fiber Volume ◽  
Filament Wound

Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture the pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition and material properties of matrix and fiber. The designed ideal pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, the effect of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance was investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the layer-by-layer thickness and fiber volume fraction variation. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization test was performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.

Influence of Layer-Thickness Ratio on Magnetic Properties in F-La2/3Ca1/3MnO3/AF-La1/3Ca2/3MnO3 Bilayers

2012 ◽  
Vol 25 (7) ◽  
pp. 2193-2198 ◽  
Author(s):  
P. Prieto ◽  
L. Marín ◽  
S. M. Diez ◽  
J.-G. Ramirez ◽  
M. E. Gómez
Keyword(s):  
Magnetic Properties ◽  
Layer Thickness ◽  
Thickness Ratio ◽  
Layer Thickness Ratio

Experimental Study of Wave Loading by Internal Solitary Waves on a Submerged Slender Body

2020 ◽  
Author(s):  
Meng Ji ◽  
Ke Chen ◽  
Yunxiang You ◽  
Ruirui Zhang
Keyword(s):  
Layer Thickness ◽  
Solitary Waves ◽  
Wave Amplitude ◽  
Prediction Method ◽  
Thickness Ratio ◽  
Experimental Results ◽  
Slender Body ◽  
Internal Solitary Waves ◽  
Wave Loads ◽  
Layer Thickness Ratio

Abstract Although ocean structures are complex, they all can be disassembled into a number of simple-shaped parts. One common shape is the slender body mentioned in this paper, and we focus on studying the mechanism of this shape. Experiments were carried out to study features of wave loads exerted by internal solitary waves (ISWs) on a submerged slender body. ISWs were generated by a piston-type wave maker in a large-type density stratified two-layer fluid wave flume. Using a three-component force transducer, the force variation of three degree of freedom (DOF) on the model was recorded. A satisfactory prediction method is established for ISWs on a submerged slender body based on internal solitary wave theory, Morison equation and pressure integral. Calculations based on this new prediction method are in good agreement with the experimental results. The experimental results and calculations show that, different incident angles, wave amplitude and layer thickness ratio have great effects on the wave loads, especially transverse incident waves bring much more severely influence. Besides the forces increase linearly with the wave amplitude becoming larger, and the maximums of the horizontal forces increase with the layer thickness ratio increasing.

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