Effect of Non-Uniform Fibre Distribution along Thickness and Non-Uniform Ply Thicknesses on Frequencies of Symmetric Angle-Ply Laminates

Isaac Sfiso Radebe,Georgios A. Drosopoulos,Sarp Adali 한국섬유공학회 2022 Fibers and polymers Vol.23 No.8

Present study investigates the effect of the fibre volume ratios and the ply thicknesses on the fundamentalfrequencies and the frequency gaps of simply supported and symmetric angle-ply laminates. The elastic constants of the fibrereinforced composite are determined by using micromechanical relations. The laminate is defined as having three layers withdifferent fibre volume fractions in the surface and middle layers. The thicknesses of the surface and middle layers are alsotaken as different to improve design efficiency in terms of using the reinforcements effectively. Thus, the problem parametersaffecting the fundamental frequency and the frequency gaps are the fibre orientations, ratio of the thickness of the surfaceplies to total laminate thickness and the fibre contents of the layers. Numerical results identify the optimal values of the layerthickness ratios and the fibre orientations with respect to the fibre volume of outer layers and aspect ratios. It is observed thatthese problem parameters affect the fundamental frequency and the frequency gaps at varying degrees depending on therelative fibre volume fractions of the surface and the middle layers as well as on the relative layer thicknesses and the aspectratios. Numerical results are given for carbon and glass fibre reinforced laminates to examine their differences with respect tovarious problem parameters.

ANGLE-PLY 적층쉘의 진동특성에 관한 연구

박승진(Park Sung Jin) 대한토목학회 2011 대한토목학회논문집 A Vol.31 No.6A

Angle-Ply 적층쉘의 진동특성에 관한 최적화해석을 위해 1차전단변형이론에 의한 Ritz Method를 이용하여 이론적으로 해석하고 수치해석에 의해 고유진동수와 진동모드를 해석하여 적층수 쉘의 지지조건 적층순서에 미치는 영향을 정량적으로 검토하여 적층복합원통쉘의 기본고유진동수의 최적화를 위한 최적인 적층구성에 미치는 영향을 명확히 규명하고자 한다. Optimization Analysis of angle-ply laminated shells having one pair of opposite edges supported are investigated on the basis of the first-order shear deformation theory. The equations of motion of the shell are solved by the use of ritz method. A range of results are presented for composite shells to show the effects of lamination angle and number of layers on natural frequency. In addition an analysis of the strain energy distributions is used as an aid for the better understanding of the vibration characteristics of the shells.

유한 요소법에 의한 역대칭 앵글-플라이 복합적층판의 해석

이원홍 진주산업대학교 1997 論文集 Vol.36 No.-

In general, angel-ply laminated composite plates exhibit properties considerably different from those of the single-layer plate. The great difference in elastic properties between fiber and matrix materials leads to a higher ratio of in-plane Young's modulus to transverse shear modulus for laminated composite plates. Thus, to obtain the more accurate solutions to laminated composite plate problems, effects of shear strain should be considered in analyzing them. The purpose of this paper is to expend the first-order shear deformation theory by Finite Element Analysis and to clarify the problems of the laminated composite plates.

Piezothermoelastic solution for angle-ply laminated plate in cylindrical bending

Dube, G.P.,Upadhyay, M.M.,Dumir, P.C.,Kumar, S. Techno-Press 1998 Structural Engineering and Mechanics, An Int'l Jou Vol.6 No.5

Generalised plane strain solution is presented for simply supported, angle-ply laminated hybrid plate under cylindrical bending. The arbitrary constants in the general solution of the governing differential equations are obtained from the boundary and interface conditions. The response of hybrid plates to sinusoidal loads is obtained to illustrate the effect of the thickness parameter and the ply-angle. The classical lamination theory and the first order shear deformation theory are also assessed.

부직포가 예각 적층판의 기계적 거동에 미치는 효과

정성균 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.6

This paper investigates the mechanical characteristics of angle-ply laminates with non-woven carbon tissue. The laminates were made by inserting non-woven carbon tissue at the interface. Specimens were rounded near the tabs by grinding and polishing to reduce the stress concentration. Cyclic loads were applied to the specimens and the stress and fatigue life curves were obtained. The matrix crack density was also evaluated to check the effects of non-woven carbon tissue on the fracture resistance of composite laminates. C-Scan technique was used to evaluate the delamination, and SEM was used to understand the fracture mechanisms of the laminates. Experimental results show that the fatigue strength and life of composite laminates were increased by inserting non-woven carbon tissues. The results also show that the matrix crack density and delamination area were reduced by inserting non-woven carbon tissues.

Static analysis of laminated reinforced composite plates using a simple first-order shear deformation theory

Kada Draiche,Abdelmoumen Anis Bousahla,Abdelouahed Tounsi,Afaf S. Alwabli,Abdeldjebbar Tounsi,S.R. Mahmoud 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.24 No.4

This paper aims to present an analytical model to predict the static analysis of laminated reinforced composite plates subjected to sinusoidal and uniform loads by using a simple first-order shear deformation theory (SFSDT). The most important aspect of the present theory is that unlike the conventional FSDT, the proposed model contains only four unknown variables. This is due to the fact that the inplane displacement field is selected according to an undetermined integral component in order to reduce the number of unknowns. The governing differential equations are derived by employing the static version of principle of virtual work and solved by applying Navier’s solution procedure. The non-dimensional displacements and stresses of simply supported antisymmetric cross-ply and angle-ply laminated plates are presented and compared with the exact 3D solutions and those computed using other plate theories to demonstrate the accuracy and efficiency of the present theory. It is found from these comparisons that the numerical results provided by the present model are in close agreement with those obtained by using the conventional FSDT.

Analytical free vibration solution for angle-ply piezolaminated plate under cylindrical bending: A piezo-elasticity approach

Singh, Agyapal,Kumari, Poonam Techno-Press 2020 Advances in computational design Vol.5 No.1

For the first time, an accurate analytical solution, based on coupled three-dimensional (3D) piezoelasticity equations, is presented for free vibration analysis of the angle-ply elastic and piezoelectric flat laminated panels under arbitrary boundary conditions. The present analytical solution is applicable to composite, sandwich and hybrid panels having arbitrary angle-ply lay-up, material properties, and boundary conditions. The modified Hamiltons principle approach has been applied to derive the weak form of governing equations where stresses, displacements, electric potential, and electric displacement field variables are considered as primary variables. Thereafter, multi-term multi-field extended Kantorovich approach (MMEKM) is employed to transform the governing equation into two sets of algebraic-ordinary differential equations (ODEs), one along in-plane (x) and other along the thickness (z) direction, respectively. These ODEs are solved in closed-form manner, which ensures the same order of accuracy for all the variables (stresses, displacements, and electric variables) by satisfying the boundary and continuity equations in exact manners. A robust algorithm is developed for extracting the natural frequencies and mode shapes. The numerical results are reported for various configurations such as elastic panels, sandwich panels and piezoelectric panels under different sets of boundary conditions. The effect of ply-angle and thickness to span ratio (s) on the dynamic behavior of the panels are also investigated. The presented 3D analytical solution will be helpful in the assessment of various 1D theories and numerical methods.

TWO-PARAMETER 탄성지반위에 놓인 고차전단변형 역대칭 앵글-플라이 적층판의 정적 및 동적해석

이원홍 진주산업대학교 건설기술연구소 1998 건설기술연구소보 Vol.1 No.-

Static and Transient results for a anti-symmetric angle-ply laminated plate on two-parameter elastic foundations base on a higher-order shear deformation theory are presented. The effects on central deflection by plate thickness ratio, material modulus ratio, shear and winkler modulus of elastic foundations are investigated. To validate the derived equations, the obtained deflections of simply supported orthotropic plates are compared with those of Timoshenko. The information presented should be useful to composite-structure designers, to researchers seeking to obtain better correlation between theory and experiment and to numerical analysts in checking out their programs.

Evaluation of modeling techniques for a type III hydrogen pressure vessel (70 MPa) made of an aluminum liner and a thick carbon/epoxy composite for fuel cell vehicles

Son, D.S.,Chang, S.H. Pergamon Press ; Elsevier Science Ltd 2012 International journal of hydrogen energy Vol.37 No.3

Stress distributions in the composite layers of a Type III hydrogen pressure vessel composed of a thin aluminum liner (5 mm) and a thick composite laminate (45 mm) were calculated by using three different modeling techniques. The results were analyzed and compared with the plausible stress distribution calculated by a full ply-based modeling technique. A laminate-based modeling technique underestimated the generated stresses especially at the border between the cylinder and dome parts. A hybrid modeling technique combining a laminate-based modeling for the dome part with a ply-based modeling for the cylinder part was also tried, but it overestimated the generated stresses at the border. In order for the ply-based modeling technique to carry out precise analysis, a fiber trajectory function for the dome part was derived and the composite thickness variation was also considered.

섬유의 적층 각도에 따른 섬유 금속 적층판의 압입 손상 거동

한경섭,남현욱,정성욱,Han, Gyeong-Seop,Nam, Hyeon-Uk,Jeong, Seong-Uk 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.5

In this research, the effects of fiber stacking sequence on damage behaviors of FML(Fiber Metal Laminates) subject to indentation loading. SOP (Singly Oriented Ply) FML and angle ply FML were fabricated to study fiber orientation effects and angle ply effects. FML were fabricated by using 1050 aluminum laminate and carbon/epoxy prepreg. To increase adhesive bonding strength, Al laminate was etched using FPL methods. The static indentation test were conducted by using UTM under the 2side clamped conditions. During the tests, load and displacement curve and crack initiation and propagation behaviors were investigated. As fiber orientation angle increases, the crack initiation load of SOP FML increases because the stiffness induced by fiber orientation is increased. The penetration load of SOP FML is influenced by the deformation tendency and boundary conditions. However, the macro-crack of angle ply FML was initiated by fiber breakage of lower ply because angle plies in Angle ply FML prevents the crack growth and consolidation. The Angle ply FML has a critical cross-angle which prevent crack growth and consolidation. Damage behavior of Angle ply FML is changed around the critical cross-angle.