Analytical solution for bending analysis of soft-core composite sandwich plates using improved high-order theory

M.M. Kheirikhah,S.M.R. Khalili,K. Malekzadeh Fard 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.1

In the present paper, an improved high-order theory is used for bending analysis of soft-core sandwich plates. Third-order plate assumptions are used for face sheets and quadratic and cubic functions are assumed for transverse and in-plane displacements of the orthotropic soft core. Continuity conditions for transverse shear stresses at the interfaces as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of the plate are satisfied. Also, transverse flexibility and transverse normal strain and stress of the orthotropic core are considered. The equations of motion and boundary conditions are derived by principle of minimum potential energy. Analytical solution for bending analysis of simply supported sandwich plates under various transverse loads are presented using Navier’s solution. Comparison of the present results with those of the three-dimensional theory of elasticity and some plate theories in the literature confirms the accuracy of the proposed theory.

Analytical solution for bending analysis of soft-core composite sandwich plates using improved high-order theory

Kheirikhah, M.M.,Khalili, S.M.R.,Fard, K. Malekzadeh Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.1

In the present paper, an improved high-order theory is used for bending analysis of soft-core sandwich plates. Third-order plate assumptions are used for face sheets and quadratic and cubic functions are assumed for transverse and in-plane displacements of the orthotropic soft core. Continuity conditions for transverse shear stresses at the interfaces as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of the plate are satisfied. Also, transverse flexibility and transverse normal strain and stress of the orthotropic core are considered. The equations of motion and boundary conditions are derived by principle of minimum potential energy. Analytical solution for bending analysis of simply supported sandwich plates under various transverse loads are presented using Navier's solution. Comparison of the present results with those of the three-dimensional theory of elasticity and some plate theories in the literature confirms the accuracy of the proposed theory.

복합신소재 적층 면판을 갖는 경사 콘크리트 판의 자유진동에 미치는 비선형 전단변형 효과

이상열(Lee Sang-Youl),노명현(Noh Myunghyun),박대효(Park Taehyo) 대한토목학회 2007 대한토목학회논문집 A Vol.27 No.2A

본 연구에서는 복합 신소재로 이루어진 적층 면판을 갖는 하이브리드 형태 경사 콘크리트 판의 자유진동에 미치는 비선형전단 변형 효과를 분석하였다. 경사 콘크리트 판구조물의 복합재료 면판에 대하여 비선형 고차항 판이론을 적용하기 위하여 개발된 유한요소 프로그램은 Lagrangian 및 Hermite 보간함수를 병용하여 절점 당 7개의 자유도를 갖는다. 전단보정계수의 가정을 필요로 하지 않고 전단변형의 3차항 비선형 특성이 고려된 본 논문의 경사 요소는 국부좌표계와 전체좌표계에 대한 좌표변환행렬에 의하여 요소 당 28×28의 국부요소행렬로 구성된다. 본 해석 프로그램의 결과는 기존의 고전적 이론 및 일차항 이론에 의한 문헌 결과와 비교ㆍ분석하였으며, 적층 배열, 경사각도, 그리고 기하학적 형상 변화 등의 다양한 매개변수 연구를 수행하였다. 본 연구에서는 특히 경사각도에 따라 예측하기 힘든 복잡한 거동을 보이는 복합적층 경사 콘크리트 판구조물의 자유진동에 미치는 비선형 전단 변형 효과를 분석하는데 초점을 두었다. This study investigates nonlinear effects of the shear deformation on the free vibration of concrete plates with laminated composite face plates. In this paper, the mixed finite element method using Lagrangian and Hermite interpolation functions is adopted and a nonlinear high-order plate theory is used to skew concrete plates. The theory accounts for parabolic distribution of the transverse shear stress and requires no shear correction factors supposed in the first-order plate theory. The results in this study are compared with those of available literatures for the conventional and first-order plate theory. Sample studies are carried out for various layup configurations, skew angles, and geometric shapes of plates. The significance of the nonlinear shear deformation effects in analyzing complex skew concrete structures with laminated facings is enunciated in this paper.

고차전단변형 판이론을 이용한 채널단면을 갖는 복합적층 절판 구조물의 유한요소 진동 해석

한국전산구조공학회 한국전산구조공학회 2004 한국전산구조공학회논문집 Vol.17 No.1

본 연구에서는 유한요소법을 이용한 채널단면을 갖는 복합재료 적층 구조물의 자유진동을 다룬다. 복합적층 절판구조물에 고차항 판이론을 적용하기 위하여 개발된 유한요소 프로그램은 Lagrangian 및 Hermite 보간함수를 병용하여 면내회전각 자유도를 포함한 절점 당 8개의 자유도를 갖는다. 전단보정계수의 가정을 필요로 하지 않고 전단변형의 3차항 비선형 특성이 고려된 본 논문의 절판 요소는 국부좌표계와 전체좌표계에 대한 좌표변환행렬에 의하여 요소 당 32의 국부요소행렬로 구성된다. 본 해석 프로그램의 결과는 기존의 고전적 이론 및 일차항 이론에 의한 문헌 결과와 비교ㆍ분석하였으며, 화이버 보강각도, 길이-두께비, 기하학적 형상 변화 등의 다양한 매개변수 연구를 수행하였다. 본 연구에서는 특히 경계조건 및 길이-두께비 변화에 따라 예측하기 힘든 복잡한 거동을 보이는 복합적층 채널단면 구조물의 자유진동에 대하여 정밀한 고차항 이론 적용에 의한 엄밀 해석의 필요성을 제기하였다. This study deals with free vibrations of laminated composite structures with a channel section using finite element method. In this paper, the mixed finite element method using Lagrangian and Hermite interpolation functions is adopted and a high-order plate theory is used to analyze laminated composite non-prismatic folded plates with a channel section more accurately for free vibration. The theory accounts for parabolic distribution of the transverse shear stress and requires no shear correction factors supposed in the first-order plate theory. An 3232 matrix is assembled to transform the system element matrices from the local to global coordinates using a coordinate transformation matrix, in which an eighth drilling degree of freedom (DOF) per node is appended to the existing 7-DOF system. The results in this study are compared with those of available literatures for the conventional and first-order plate theory. Sample studies are carried out for various layup configurations and length-thickness ratio, and geometric shapes of plates. The significance of the high-order plate theory in analyzing complex composite structures with a channel section is enunciated in this paper.

Free vibration of FGM plates with porosity by a shear deformation theory with four variables

Mahfoud Yousfi,Hassen Ait Atmane,Mustapha Meradjah,Abdelouahed Tounsi,Riadh Bennai 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.3

In this work, a high order hyperbolic shear deformation theory with four variables is presented to study the vibratory behavior of functionally graduated plates. The field of displacement of the theory used in this work is introduced indeterminate integral variables. In addition, the effect of porosity is studied. It is assumed that the material characteristics of the porous FGM plate, varies continuously in the direction of thickness as a function of the power law model in terms of volume fractions of constituents taken into account the homogeneous distribution of porosity. The equations of motion are obtained using the principle of virtual work. An analytical solution of the Navier type for free vibration analysis is obtained for a FGM plate for simply supported boundary conditions. A comparison of the results obtained with those of the literature is made to verify the accuracy and efficiency of the present theory. It can be concluded from his results that the current theory is not only accurate but also simple for the presentation of the response of free vibration and the effect of porosity on the latter.

Free vibration of FGM plates with porosity by a shear deformation theory with four variables

Yousfi, Mahfoud,Atmane, Hassen Ait,Meradjah, Mustapha,Tounsi, Abdelouahed,Bennai, Riadh Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.3

In this work, a high order hyperbolic shear deformation theory with four variables is presented to study the vibratory behavior of functionally graduated plates. The field of displacement of the theory used in this work is introduced indeterminate integral variables. In addition, the effect of porosity is studied. It is assumed that the material characteristics of the porous FGM plate, varies continuously in the direction of thickness as a function of the power law model in terms of volume fractions of constituents taken into account the homogeneous distribution of porosity. The equations of motion are obtained using the principle of virtual work. An analytical solution of the Navier type for free vibration analysis is obtained for a FGM plate for simply supported boundary conditions. A comparison of the results obtained with those of the literature is made to verify the accuracy and efficiency of the present theory. It can be concluded from his results that the current theory is not only accurate but also simple for the presentation of the response of free vibration and the effect of porosity on the latter.

고 정확도의 인공신경망과 그 활용

박지은,이덕균 한국정보통신학회 2024 한국정보통신학회논문지 Vol.28 No.6

인공지능의 성공은 인공지능을 다양한 분야에 적용하게 하는 계기가 되고 있다. 과학 분야, 특히 과학계산 분야에서 인공지능을 활용하려는 시도가 많이 이루어지고 있다. 그러나 과학계산에서 인공지능의 활용은 다른 분야와 다르게 더디게 발전하고 있다. 이러한 요인에는 여러 가지가 있지만, 과학계산은 정확하고 정밀한 값을 요구한다. 기존의 인공신경망을 이용한 과학계산에서 나타나는 어려움을 분석하고, 정밀 계산을 위한 고 정확도 인공신경망을 제안한다. 정확하고 정밀한 계산을 위한 고 정확도 근사이론을 인공신경망에 적용한다. 우리는 수치 실험에서 보간법, 과학계산, 이미지 분류 등 다양하게 실험하여 고 정확도 인공신경망 방법의 효과를 확인한다. 보간법에서는 오차의 값이 기존방법과 우리의 방법이 각각 0.03과 0.001로, 과학계산에서는 각각 43.28과 4.42로, 이미지 분류에서는 정답률이 각각 73%와 77.6%로 나왔다. The success of artificial intelligence is becoming an opportunity to apply artificial intelligence to various fields. Many attempts are being made to utilize artificial intelligence in the field of science, especially in scientific computing. However, unlike other fields, the use of artificial intelligence in scientific computing is developing slowly. There are many factors involved in these factors, but scientific calculations require accurate and precise values. As existing artificial intelligence performs scientific calculations using artificial neural networks, difficulties that arise are analyzed and high-accuracy artificial neural networks for precise calculations are proposed. High-accuracy approximation theory is applied to artificial neural networks for accurate and precise calculations. We verify the effectiveness of the high-accuracy artificial neural network method through various experiments such as interpolation, scientific calculation, and image classification in numerical experiments. In the interpolation method, the error values ​​for the existing method and our method were 0.03 and 0.001, respectively, in scientific calculation, the error values ​​were 43.28 and 4.42, respectively, and in image classification, the correct answer rates were 73% and 77.6%, respectively.

Single variable shear deformation model for bending analysis of thick beams

Abdelbari, Salima,Amar, Lemya Hanifi Hachemi,Kaci, Abdelhakim,Tounsi, Abdelouahed Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.3

In this work, a new trigonometry theory of shear deformation is developed for the static analysis of thick isotropic beams. The number of variables used in this theory is identical to that required in the theory of Euler-Bernoulli, sine function is used in the displacement field in terms of the coordinates of the thickness to represent the effects of shear deformation. The advantage of this theory is that shear stresses can be obtained directly from the relationships constitute, while respecting the boundary conditions at the free surface level of the beam. Therefore, this theory avoids the use of shear correction coefficients. The differential equilibrium equations are obtained using the principle of virtual works. A thick isotropic beam is considered, whose numerical study to show the effectiveness of this theory.

Single variable shear deformation model for bending analysis of thick beams

Salima Abdelbari,Lemya Hanifi Hachemi Amar,Abdelhakim Kaci,Abdelouahed Tounsi 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.3

In this work, a new trigonometry theory of shear deformation is developed for the static analysis of thick isotropic beams. The number of variables used in this theory is identical to that required in the theory of Euler-Bernoulli, sine function is used in the displacement field in terms of the coordinates of the thickness to represent the effects of shear deformation. The advantage of this theory is that shear stresses can be obtained directly from the relationships constitute, while respecting the boundary conditions at the free surface level of the beam. Therefore, this theory avoids the use of shear correction coefficients. The differential equilibrium equations are obtained using the principle of virtual works. A thick isotropic beam is considered, whose numerical study to show the effectiveness of this theory.

Simulation and modeling for stability analysis of functionally graded non-uniform pipes with porosity-dependent properties

Peng Zhang,Jun-song Jin,Tayebeh Mahmoudi 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.48 No.2

The present paper examines the stability analysis of the buckling differentiae of the small-scale, non-uniform porosity-dependent functionally graded (PD-FG) tube. The high-order beam theory and nonlocal strain gradient theory are operated for the mathematical modeling of nanotubes based on the Hamilton principle. In this paper, the external radius function is non-uniform. In contrast, the internal radius is uniform, and the cross-section changes along the tube length due to these radius functions based on the four types of useful mathematical functions. The PD-FG material distributions are varied in the radial direction and made with ceramics and metals. The governing partial differential equations (PDEs) and associated boundary conditions are solved via a numerical method for different boundary conditions. The received outcomes concerning different presented parameters are valuable to the design and production of small-scale devices and intelligent structures.