This article discusses the dynamic response of Bernoulli-Euler straight beam with angular elastic supports subjected to moving load with variable velocity. A new engineering approach for determination of the dynamic effect from the moving load on the stressed and strained state of the beam has been developed. A dynamic coefficient, a ratio of the dynamic to the static deflection of the beam, has been defined on the base of an infinite geometrical absolutely summable series. Generalization of the R. Willis\' equation has been carried out: generalized boundary conditions have been introduced; the generalized elastic curve\'s
equation on the base of infinite trigonometric series method has been obtained; the forces of inertia from
normal and Coriolis accelerations and reduced beam mass have been taken into account. The influence of the boundary conditions and kinematic characteristics of the moving load on the dynamic coefficient has been investigated. As a result, the dynamic stressed and strained state has been obtained as a multiplication of the static one with the dynamic coefficient. The developed approach has been compared with a finite element one for a concrete engineering case and thus its authenticity has been proved.
Bernoulli-Euler beam; moving load; dynamic stress; dynamic deflection; elastic supports; FE
J.T. Maximov: Technical University of Gabrovo, Department of Applied Mechanicas, 5300 Gabrovo, Bulgaria
A proper physical modeling of infilled building frame-foundation beam-soil mass interaction system is needed to predict more realistic and accurate structural behavior under static vertical loading. This is achieved via finite element method considering the superstructure, foundation and soil mass as a single integral compatible structural unit. The physical modelling is achieved via use of finite element method, which requires the use of variety of isoparametric elements with different degrees of freedom. The unbounded domain of the soil mass has been discretized with coupled finite-infinite elements to achieve
computational economy. The nonlinearity of soil mass plays an important role in the redistribution of forces
in the superstructure. The nonlinear behaviour of the soil mass is modeled using hyperbolic model. The incremental-iterative nonlinear solution algorithm has been adopted for carrying out the nonlinear elastic interaction analysis of a two-bay two-storey infilled building frame. The frame and the infill have been considered to behave in linear elastic manner, whereas the subsoil in nonlinear elastic manner. In this paper, the computational methodology adopted for nonlinear soil-structure interaction analysis of infilled
frame-foundation-soil system has been presented.
Paper discusess a dynamic engineering problem of a mass attached to a pendulum sliding along a cable. In this problem the pendulum mass and the cable are coupled together in a model described by a system of differential algebraic equations (DAE). In the paper we have presented formulation of the system of differential equations that models the problem and determination of the initial conditions. The developed model is general in a sense of free choice of support location, elastic cable properties, pendulum length and inclusion of braking forces. Examples illustrate and validate the model.
elastic rope/cable; sliding mass; sliding pendulum; differential-algebraic equations
Ivica Kožar and Neira Torić Malić: Department for Computer Modeling, Faculty of Civil Engineering, University of Rijeka, Radmile Matejčić 3, 51 000 Rijeka, Croatia
The study deals with the physical modeling of a typical building frame resting on pile foundation and embedded in cohesive soil mass using complete three-dimensional finite element analysis. Two different pile groups comprising four piles (2X2) and nine piles (3 X3) are considered. Further, three different pile diameters along with the various pile spacings are considered. The elements of the superstructure frame and those of the pile foundation are descretized using twenty-node isoparametric continuum elements. The interface between the pile and pile and soil is idealized using sixteen-node isoparametric surface elements. The current study is an improved version of finite element modeling for the soil elements compared to the one reported in the literature (Chore and Ingle 2008). The soil elements are discretized using eight-, nine- and twelve-node continuum elements. Both the elements of superstructure and
substructure (i.e., foundation) including soil are assumed to remain in the elastic state at all the time. The
interaction analysis is carried out using sub-structure approach in the parametric study. The total stress
analysis is carried out considering the immediate behaviour of the soil. The effect of various parameters of the pile foundation such as spacing in a group and number piles in a group, along with pile diameter, is evaluated on the response of superstructure. The response includes the displacement at the top of the frame and bending moment in columns. The soil-structure interaction effect is found to increase displacement in the range of 58 -152% and increase the absolute maximum positive and negative moments in the column in the range of 14-15% and 26-28%, respectively. The effect of the soil- structure interaction is observed to be
significant for the configuration of the pile groups and the soil considered in the present study.
soil-structure interaction; pile groups; pile spacing; pile diameter; top displacement; bending
P.A. Dode: Department of Civil Engineering, Manoharbhai Patel Institute of Engineering and Technology,
H.S. Chore: Department of Civil Engineering, Datta Meghe College of Engineering, Sector-3, Airoli, Navi Mumbai- 400 708, India
D.K. Agrawal:Department of Civil Engineering, B.D. College of Engineering, At Post: Sewagram, District: Wardha-442102, India
This study investigated the collision of ships withfloating pier structures. The nature of the collision phenomenon is complex, and the understanding of it has developed through the modelling of offshore structures. ABAQUS software was used to investigate the collision phenomenon. The interaction between the ship and structural system was modelled, and the stress distribution both at thetime of collision and afterwardswasobserved and modelled. The strain energy absorption by different structural partswas calculated and comparisonswere made.
ship; collision; floating; pier; interaction; ABAQUS
Amin Chegenizadeh, Behzad Ghadimi and Hamid Nikraz: Department of Civil Engineering, Curtin University, Perth, Australia