• Title, Summary, Keyword: Quasi-elastic method

Search Result 51, Processing Time 0.026 seconds

Nonlinear Viscoelastic Analysis of Reticulated Spatial Truss Composed of Composite Materials (복합재료 그물형 공간 트러스의 점탄성적 비선형 해석)

  • Han, Sung Cheon;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
    • /
    • v.13 no.6
    • /
    • pp.661-672
    • /
    • 2001
  • The present study is concerned with the arc-length method in the investigation of the large deflection behavior of spatial structures with composite materials. This study should be able to trace the main equilibrium path by automatically varying the arc-length size of individual solution steps with the variation of the curvature of the nonlinear equilibrium path. A quasi-elastic method is used for the solution for viscoelastic analysis of the reticulated spatial structures. Elastic modulus of composite materials is defined by micro mechanical materials modeling method and nonlinear equilibrium path is traced with various load types. To demonstrate the effectiveness of the present strategies, numerical examples of reticulated spatial truss is given and compared with solutions using other methods.

  • PDF

The mixed finite element for quasi-static and dynamic analysis of viscoelastic circular beams

  • Kadioglu, Fethi;Akoz, A. Yalcin
    • Structural Engineering and Mechanics
    • /
    • v.15 no.6
    • /
    • pp.735-752
    • /
    • 2003
  • The quasi-static and dynamic responses of a linear viscoelastic circular beam on Winkler foundation are studied numerically by using the mixed finite element method in transformed Laplace-Carson space. This element VCR12 has 12 independent variables. The solution is obtained in transformed space and Schapery, Dubner, Durbin and Maximum Degree of Precision (MDOP) transform techniques are employed for numerical inversion. The performance of the method is presented by several quasi-static and dynamic example problems.

Free vibration of functionally graded plates resting on elastic foundations based on quasi-3D hybrid-type higher order shear deformation theory

  • Zaoui, Fatima Zohra;Tounsi, Abdelouahed;Ouinas, Djamel
    • Smart Structures and Systems
    • /
    • v.20 no.4
    • /
    • pp.509-524
    • /
    • 2017
  • In this article, a free vibration analysis of functionally graded (FG) plates resting on elastic foundations is presented using a quasi-3D hybrid-type higher order shear deformation theory. Undetermined integral terms are employed in the proposed displacement field and modeled based on a hybrid-type (sinusoidal and parabolic) quasi-3D HSDT with five unknowns in which the stretching effect is taken into account. Thus, it can be said that the significant feature of this theory is that it deals with only 5 unknowns as the first order shear deformation theory (FSDT). The elastic foundation parameters are introduced in the present formulation by following the Pasternak (two-parameter) mathematical model. Equations of motion are obtained via the Hamilton's principles and solved using Navier's method. Accuracy of the proposed theory is confirmed by comparing the results of numerical examples with the ones available in literature.

Kineto-Elasto Static and Dynamic Responses of a Fully Elastic Linked, Four-bar Mechanism

  • Sin, Jung-Ho;Kinzel, Gary L.
    • 한국기계연구소 소보
    • /
    • /
    • pp.99-109
    • /
    • 1987
  • Mechanisms with fully elastic members must consider both inertial forces due to the rigid motion of mechanisms and due to the elastic vibration of links. The main objectives of the kineto-elasto static and dynamic analyses are to calculate the quasi-static and the time-domain responses, respectively. An iterative transfer matrix method is used for a four-bar, fully elastic linked mechanism. Houbolt direct integration scheme is incorporated for the inertial effects due to the elastic link vibration. The analytical results are compared with the experimental responses and both responses show in good agreement.

  • PDF

Eigenfrequencies of advanced composite plates using an efficient hybrid quasi-3D shear deformation theory

  • Guerroudj, Hicham Zakaria;Yeghnem, Redha;Kaci, Abdelhakim;Zaoui, Fatima Zohra;Benyoucef, Samir;Tounsi, Abdelouahed
    • Smart Structures and Systems
    • /
    • v.22 no.1
    • /
    • pp.121-132
    • /
    • 2018
  • This research investigates the free vibration analysis of advanced composite plates such as functionally graded plates (FGPs) resting on a two-parameter elastic foundations using a hybrid quasi-3D (trigonometric as well as polynomial) higher-order shear deformation theory (HSDT). This present theory, which does not require shear correction factor, accounts for shear deformation and thickness stretching effects by a sinusoidal and parabolic variation of all displacements across the thickness. Governing equations of motion for FGM plates are derived from Hamilton's principle. The closed form solutions are obtained by using Navier technique, and natural frequencies are found, for simply supported plates, by solving the results of eigenvalue problems. The accuracy of the present method is verified by comparing the obtained results with First-order shear deformation theory, and other predicted by quasi-3D higher-order shear deformation theories. It can be concluded that the proposed theory is efficient and simple in predicting the natural frequencies of functionally graded plates on elastic foundations.

Elastic modulus in large concrete structures by a sequential hypothesis testing procedure applied to impulse method data

  • Antonaci, Paola;Bocca, Pietro G.;Sellone, Fabrizio
    • Structural Engineering and Mechanics
    • /
    • v.26 no.5
    • /
    • pp.499-516
    • /
    • 2007
  • An experimental method denoted as Impulse Method is proposed as a cost-effective non-destructive technique for the on-site evaluation of concrete elastic modulus in existing structures: on the basis of Hertz's quasi-static theory of elastic impact and with the aid of a simple portable testing equipment, it makes it possible to collect series of local measurements of the elastic modulus in an easy way and in a very short time. A Hypothesis Testing procedure is developed in order to provide a statistical tool for processing the data collected by means of the Impulse Method and assessing the possible occurrence of significant variations in the elastic modulus without exceeding some prescribed error probabilities. It is based on a particular formulation of the renowned sequential probability ratio test and reveals to be optimal with respect to the error probabilities and the required number of observations, thus further improving the time-effectiveness of the Impulse Method. The results of an experimental investigation on different types of plain concrete prove the validity of the Impulse Method in estimating the unknown value of the elastic modulus and attest the effectiveness of the proposed Hypothesis Testing procedure in identifying significant variations in the elastic modulus.

Effect of stacking sequence on thermal stresses in laminated plates with a quasi-square cutout using the complex variable method

  • Chaleshtari, Mohammad H. Bayati;Khoramishad, Hadi
    • Structural Engineering and Mechanics
    • /
    • v.77 no.2
    • /
    • pp.245-259
    • /
    • 2021
  • In this research, the influence of the laminate stacking sequence on thermal stress distribution in symmetric composite plates with a quasi-square cutout subjected to uniform heat flux is examined analytically using the complex variable technique. The analytical solution is obtained based on the thermo-elastic theory and the Lekhnitskii's method. Furthermore, by employing a suitable mapping function, the solution of symmetric laminates containing a circular cutout is extended to the quasi-square cutout. The effect of important parameters including the stacking sequence of laminates, the angular position, the bluntness, the aspect ratio of cutout, the flux angle and the composite material are examined on the thermal stress distribution. It is found out that the circular shape for cutout may not necessarily be the optimum geometry for all stacking sequences. The finite element analysis results are used to validate the analytical solution.

Bending and Vibration Analysis of Elastic and Viscoelastic Laminated Composite Structures using an Improved Higher-order Theory (개선된 고차이론을 이용한 복합재료 적층구조물의 탄성 및 점탄성적 휨, 진동해석)

  • Han, Sung Cheon;Yoo, Yong Min;Park, Dae Yong;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
    • /
    • v.14 no.1
    • /
    • pp.1-12
    • /
    • 2002
  • To obtain more accurate responses of laminated composite structures, the effect of transverse shear deformation, transverse normal strain/stress and a nonlinear variation of in-plane displacements with respect to the thickness coordinate need to be considered in the analysis. The improved higher-order theory is used to determine the deflections and natural frequencies of laminated composite structures. A quasi-elastic method is used for the solution of viscoelastic analysis of the laminated composite plates and sandwiches. Solutions of simply-supported laminated composite plates and sandwiches are obtained and the results are compared with those by the 3D elasticity theory and other theories. The improved theory proposed in this paper is shown to predict the deflections and natural frequencies more accurately than all other theories.

Dynamic Analysis of Space Structure by Using Perturbation Method (섭동법을 이용한 우주 구조물의 동적 운동 해석)

  • Kwak, Moon-K.;Seong, Kwan-Jae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.674-679
    • /
    • 2005
  • This paper is concerned with the application of perturbation method to the dynamic analysis of space structure floating in space. In dealing with the dynamics of space structure, the use of Lagrange's equations of motion in terms of quasi-coordinates were suggested to derive hybrid equations of motion for rigid-body translations and elastic vibrations. The perturbation method is then applied to the hybrid equations of motion along with discretization by means of admissible functions. This process is very tiresome. Recently, a new approach that applies the perturbation method to the Lagrange's equations directly was proposed and applied to the two-dimensional floating structure. In this paper, we propose the application of the perturbation method to the Lagrange's equations of motion in terms of quasi-coordinates. Theoretical derivations show the efficacy of the proposed method.

  • PDF

Dynamic Analysis of Space Structure by Using Perturbation Method (섭동법을 이용한 우주 구조물의 동적 운동 해석)

  • Seong, Kwan-Jae;Kwak, Moon K.
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.15 no.9
    • /
    • pp.1030-1036
    • /
    • 2005
  • This paper is concerned with the application of perturbation method to the dynamic analysis of space structure floating in space. In dealing with the dynamics of space structure, the use of Lagrange's equations of motion in terms of quasi-coordinates were suggested to derive hybrid equations of motion for rigid-body translations and elastic vibrations. The perturbation method is then applied to the hybrid equations of motion along with discretization by means of admissible functions. This process is very tiresome. Recently, a new approach that applies the perturbation method to the Lagrange's equations directly was proposed and applied to the two-dimensional floating structure. In this paper. we propose the application of the perturbation method to the Lagrange's equations of motion in terms of quasi-coordinates. Theoretical derivations show the efficacy of the proposed method.