scholarly journals Parametric Optimization of Isotropic and Composite Axially Symmetric Shells Subjected to External Pressure and Twisting

2021 ◽  
Vol 5 (5) ◽  
pp. 128
Author(s):  
Marek Barski ◽  
Paweł J. Romanowicz ◽  
Małgorzata Chwał ◽  
Adam Stawiarski
Keyword(s):  
Isotropic Material ◽  
Orientation Angle ◽  
Optimization Procedure ◽  
Middle Surface ◽  
External Pressure ◽  
Optimal Structure ◽  
Constant Thickness ◽  
Geometrical Shape ◽  
Axially Symmetric ◽  
Fiber Orientation Angle

The present paper is devoted to the problem of the optimal design of thin-walled composite axially symmetric shells with respect to buckling resistance. The optimization problem is formulated with the following constraints: namely, all analyzed shells have identical capacity and volume of material. The optimization procedure consists of four steps. In the first step, the initial calculations are made for cylindrical shells with non-optimal orientation of layers and these results are used as the reference for optimization. Next, the optimal orientations of layers for cylindrical shapes are determined. In the third step, the optimal geometrical shape of a middle surface with a constant thickness is determined for isotropic material. Finally, for the assumed shape of the middle surface, the optimal fiber orientation angle θ of the composite shell is appointed. Such studies were carried for three cases: pure external pressure, pure twisting, and combined external pressure with twisting. In the case of shells made of isotropic material the obtained results are compared with the optimal structure of uniform stability, where the analytical Shirshov’s local stability condition is utilized. In the case of structures made of composite materials, the computations are carried out for two different materials, where the ratio of E1/E2 is equal to 17.573 and 3.415. The obtained benefit from optimization, measured as the ratio of critical load multiplier computed for reference shell and optimal structure, is significant. Finally, the optimal geometrical shapes and orientations of the layers for the assumed loadings is proposed.

scholarly journals Optimization of Laminated Composite Plates for Maximum Biaxial Buckling Load

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Pham Dinh Nguyen ◽  
Quang-Viet Vu ◽  
George Papazafeiropoulos ◽  
Hoang Thi Thiem ◽  
Pham Minh Vuong ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Buckling Load ◽  
Biaxial Compression ◽  
Laminated Composite Plates ◽  
Design Variables ◽  
Fiber Orientation Angle

This paper proposes an optimization procedure for maximization of the biaxial buckling load of laminated composite plates using the gradient-based interior-point optimization algorithm. The fiber orientation angle and the thickness of each lamina are considered as continuous design variables of the problem. The effect of the number of layers, fiber orientation angles, thickness and length to thickness ratios on the buckling load of the laminated composite plates under biaxial compression is investigated. The effectiveness of the optimization procedure in this study is compared with previous works.

Free Vibration Analysis of the Strengthened Beams by Composite Coats

2013 ◽  
Vol 716 ◽  
pp. 595-599 ◽  
Author(s):  
Tekili Sabiha ◽  
Khadri Youcef ◽  
Merzoug Bachir
Keyword(s):  
Free Vibration ◽  
Fiber Orientation ◽  
Isotropic Material ◽  
Natural Frequencies ◽  
Sandwich Beam ◽  
Orientation Angle ◽  
Free Vibration Analysis ◽  
Computer Code ◽  
Simply Supported ◽  
Fiber Orientation Angle

The analysis of free vibration of simply-supported lamineted composite coated beams is investigated. With a core made from an isotropic material (steel) and faces made from composite material, (glass/epoxy and carbon/epoxy), two sandwich beam models are used in the study. For this purpose, a computer code is developed using MATLAB to perform the analysis of free-vibration of strengthened beams by composite coats. The effects of the variation of different parameters such as the span/depth ratio, fiber orientation angle of the coat, and thickness ratio on natural frequencies and of the beam are examined.

Buckling characteristics of cut-out borne composite stiffened hyperbolic paraboloid shell panel

2021 ◽  
pp. 146442072110058
Author(s):  
Sarmila Sahoo
Keyword(s):  
Finite Element ◽  
Orientation Angle ◽  
Buckling Load ◽  
Benchmark Problems ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Load Effect ◽  
Global Buckling ◽  
Fiber Orientation Angle ◽  
Shell Panel

The present study investigates buckling characteristics of cut-out borne stiffened hyperbolic paraboloid shell panel made of laminated composites using finite element analysis to evaluate the governing differential equations of global buckling of the structure. The finite element code is validated by solving benchmark problems from literature. Different parametric variations are studied to find the optimum panel buckling load. Laminations, boundary conditions, depth of stiffener and arrangement of stiffeners are found to influence the panel buckling load. Effect of different parameters like cut-out size, shell width to thickness ratio, degree of orthotropy and fiber orientation angle of the composite layers on buckling load are also studied. Parametric and comparative studies are conducted to analyze the buckling strength of composite hyperbolic paraboloid shell panel with cut-out.

Minimize the Deflection of Laminated Composite Plates under the External Load Using Fiber Orientation Angle

2014 ◽  
Vol 709 ◽  
pp. 144-147
Author(s):  
Ying Tao Chen ◽  
Song Xiang ◽  
Wei Ping Zhao
Keyword(s):  
Fiber Orientation ◽  
External Load ◽  
Optimization Problem ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Load Optimization ◽  
Fiber Orientation Angle ◽  
Optimization Parameters

Optimization of fiber orientation angle is studied to minimize the deflection of the laminated composite plates by the genetic algorithm. The objective function of optimization problem is the minimum deflection of laminated composite plates under the external load; optimization parameters are fiber orientation angle of laminated composite plates. The results for the optimal fiber orientation angle and the minimum deflection of the 4-layer plates are presented to demonstrate the validity of present method.

scholarly journals Tensile Mechanical Properties and Failure Modes of a Basalt Fiber/Epoxy Resin Composite Material

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jingjing He ◽  
Junping Shi ◽  
Xiaoshan Cao ◽  
Yifeng Hu
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Fiber Volume Fraction ◽  
Failure Modes ◽  
Volume Fraction ◽  
Basalt Fiber ◽  
Orientation Angle ◽  
Fiber Volume ◽  
Fiber Clustering ◽  
Fiber Orientation Angle

Uniaxial tensile tests of basalt fiber/epoxy (BF/EP) composite material with four different fiber orientations were conducted under four different fiber volume fractions, and the variations of BF/EP composite material failure modes and tensile mechanical properties were analyzed. The results show that when the fiber volume fraction is constant, the tensile strength, elastic modulus, and limiting strain of BF/EP composite material all decrease with increasing fiber orientation angle. When the fiber orientation angle is constant, the tensile strength, elastic modulus, and limiting strain of BF/EP composite material all increase with increasing fiber volume fraction. A certain degree of fiber clustering appears in the epoxy resin when the basalt fiber volume fraction is >1.2%. The fiber equidistribution coefficient and clustering fiber content were used to characterize the basalt fiber clustering effect. With the increase of fiber volume fraction, the clustering fiber content gradually increased, but the fiber equidistribution coefficient decreased. Meanwhile, based on Tsai theory, a geometric model and a tensile mechanical model of the clustering fiber are established. By considering the fiber clustering effect, the BF/EP composite material tensile strength is calculated, and the calculated values are close to the experimental results.

An Analytical Solution for Transversely Isotropic Simply Supported Thick Rectangular Plates Using Displacement Potential Functions

2011 ◽  
Vol 46 (2) ◽  
pp. 121-142 ◽  
Author(s):  
M Nematzadeh ◽  
M Eskandari-Ghadi ◽  
B Navayi Neya
Keyword(s):  
Isotropic Material ◽  
Transversely Isotropic ◽  
Numerical Results ◽  
Potential Functions ◽  
Constant Thickness ◽  
Rectangular Plates ◽  
Displacement Potential ◽  
Simply Supported ◽  
Axial Forces ◽  
Internal Forces

Using a complete set of displacement potential functions, the exact solution of three-dimensional elasticity equations of a simply supported rectangular plates with constant thickness consisting of a transversely isotropic linearly elastic material subjected to an arbitrary static load is presented. The governing partial differential equations for the potential functions are solved through the use of the Fourier method, which results in exponential and trigonometric expression along the plate thickness and the other two lengths respectively. The displacements, stresses, and internal forces are determined through the potential functions at any point of the body. To prove the validity of this approach, the analytical solutions developed in this paper are degenerated for the simpler case of plates containing isotropic material and compared with the existing solution. In addition, the numerical results obtained from this study are compared with those reported in other researches for the isotropic material, where excellent agreement is achieved for both thin and thick plates. The results show that increasing the thickness ratios of the plate causes compressive axial forces and central shear forces inside the plate. Finally, the internal forces and displacement components are calculated numerically for several kinds of transversely isotropic materials with different anisotropies and are compared with a finite element (FE) solution obtained from the ANSYS software, where the high accuracy of the present method is demonstrated. The effects of the material anisotropy are clearly revealed in the numerical results presented.

scholarly journals Surrogate Model Based Analysis of Inter-Ply Shear Stress in Fiber Reinforced Thermoplastic Composite Sheet Press Forming

2020 ◽  
Vol 10 (16) ◽  
pp. 5499
Author(s):  
Abera Tullu ◽  
Bong-Sul Lee ◽  
Ho-Yon Hwang
Keyword(s):  
Shear Stress ◽  
Surrogate Model ◽  
Orientation Angle ◽  
Computer Experiments ◽  
Thermoplastic Composite ◽  
Fiber Reinforced ◽  
Reinforced Composite ◽  
Press Forming ◽  
Forming Parameters ◽  
Fiber Orientation Angle

The anisotropic nature of fiber reinforced composite materials causes great challenges in predicting the inter-ply shear stress during forming. The complexity of understanding the functional dependency of inter-ply shear stress on multiple forming parameters such as blank temperature, pressure load, inter-ply slippage, and the relative fiber orientation angle of adjacent plies further limits the effort to produce a defect-free composite structure. Performing real experiments for various combinations of the mentioned parameters is both time consuming and economically costly. To overcome these difficulties, a surrogate-based analysis of inter-ply shear stress is proposed in this study. Based on the ranges of the forming parameters, computer experiments were performed. Using these experimental data, a radial basis function (RBF) based surrogate model that mimics inter-ply shear stress during composite press forming was developed. The fidelity of this model was checked with test data and found to be over 98% efficient.

Accuracy of Intersection Counting Method in Measurement of Fiber Orientation Angle Distribution Using Image Processing

2006 ◽  
Vol 324-325 ◽  
pp. 415-418
Author(s):  
Jin Woo Kim ◽  
Dong Gi Lee
Keyword(s):  
Image Processing ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Angle Distribution ◽  
Counting Method ◽  
Fiber Aspect Ratio ◽  
Reinforced Composite ◽  
Orientation Function ◽  
Orientation State ◽  
Fiber Orientation Angle

While mold fiber reinforced composite material to problem of occasion that high temperature compression molding, flow length in mold is overlong or when flow meets with resistance in side of mold, fiber orientation happens and big change occurs in strength or quality. Thus, in compression molding that use fiber reinforced composite material, orientation state of fiber in moldings is the most basic element that quotes various properties of matter values. Therefore, to clear orientation state of fiber establishing measurement of fiber orientation angle distribution is very important while give correction of molding condition decision, mechanical quality of moldings and guide about material design. In the study, the fiber orientation distribution of simulation figure plotted by PC is measured using image processing in order to examine the accuracy of intersection counting method. The fiber orientation function measured by intersection counting method using image processing is compared with the calculated fiber orientation function. The results show that the measured value of fiber orientation function using intersection counting method is lower than the calculated value, because the number of intersection between the scanning line and the fiber with smaller fiber aspect ratio is counted less than with larger fiber aspect ratio.

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