Numerical Simulation Of Fluid-Structure Interaction For Wind-induced Dynamic Response Of Low-rise Lightweight Buildings

Nowadays low-rise buildings such as lightweight portal frames are widely applied to the public constructions,for example,factory building,exhibition hall,fair trade market,freight yard,and so on.At the same time,owing to their light weight and large span,such kind of buildings are often very susceptible to wind effects. Previous wind disaster surveys,experiments,and theoretical researches indicate that the envelop of lightweight buildings is easier to damage in strong wind,compared with their main structures.So it is significant to study wind loads and wind-induced dynamic response for the roof structure of low-rise lightweight buildings in the field of engineering and research.The numerical simulation analysis of fluid-structure interaction(FSI) of low-rise lightweight buildings is performed by ADINA to investigate the wind-induced dynamic response in this paper.Conservation laws of structural mass and momentum are expressed in the usual Lagrangian system of coordinates on a suitable form for geometrical nonlinearity problems,while conservation principles of fluid mass and momentum are described in the Arbitrary Lagrangian Eulerian(ALE) system of coordinates.The incompressible viscous Navier-Stokes equations are assumed in the flow model.To avoid the numerical instability in the iterative solution,the 3D Flow Condition Based Interpolation(FCBI) element is employed,which is an efficient stabilized finite element solution technique.As a numerical example,the Texas Tech University Building Model is first developed by ADINA with Shear Stress Transportκ-ωModel.The trend and numerical value of wind pressure coefficients are coincident between the numerical simulation results and field measurement results,which demonstrates the wind-induced response of such structures can be simulated effectively.Taking the lightweight portal frames for instance,the aeroelastic models of low-rise buildings with different roof pitches,different height-width ratios,different length-width ratios,different height of parapets,and different length of overhanging eaves are simulated.The effects of building shapes and architectural constructions on the distribution characteristics of the surface wind load on the roofs under different parameters are analyzed on the basis of numerical results,such as wind pressure distributed coefficients and wind-induced dynamic coefficients.The main results are as follows.With the increment of the roof pitch,the windward roof suction changes little and that of the leeward roof tends to increase.The magnitude of the whole roof load tends to increase with the increment of height-width ratios and length-width ratios.After adding the parapet wall,the windward roof suction increases,which tends to increase with the parapet wall heightening;the leeward roof suction significantly decreases,which changes little with the parapet wall heightening;Moreover,the angle region of the leeward roof appears positive wind pressure,so the wind pressure coefficients of the roof with the parapet wall in the load code for the design of building structures are not comprehensive.Overhanging eaves decreases the whole roof suction.With the increment of overhanging eaves,the windward roof suction tends to decrease,and the leeward roof suction is almost invariant.Under various conditions,the wind suctions on the eaves edge region of the windward roof and the ridge are relatively large,which can be easily damaged.