Calculation of static deformation of membrane structures under the load of ponding water

Ponding refers to a phenomenon of accumulation of water on top of a structure. Even though most light weight membrane structures are designed to prevent its occurrence, it can be initiated in some cases during rainfall by an event such as drifted snow settling on the surface of the structure causing a local depression of the membrane structure. The present work proposes a method to calculate the static deformation of a membrane structure due to a given volume of ponding water. The method involves coupling of a structural solver for the membrane and a volume conserving solver representing the static behavior of an incompressible fluid. The coupling is performed in a partitioned manner with the linearized behavior of the incompressible fluid incorporated in the structural equations to accelerate the coupling iterations. Using this method, the final deformation of the structure due to ponding is calculated by applying loads due to a fixed volume of water

Coupling of structural solver and volume-conserving solver for form-finding of membrane structures subjected to ponding

The current study deals with coupling of a volume conserving solver and a structural solver to calculate the static deformation of flexible structures under the load of a given volume of water. The volume-conserving solver contains a horizontal plane representing the free surface of the fluid, which is moved in the non-linear iterations to conserve the volume. The Partitioned approach is chosen to have code modularity and reusability with many structural codes

Comparison of monolithic and partitioned approaches for ponding analysis of membrane structures

Membrane structures are vulnerable to ponding due to their large deformation characteristic. The ponding on membrane structures is usually caused by rainfall on an already deformed structure due to a seeding event such as snow accumulation. This paper discusses two monolithic methods and a partitioned method for determining the static deformation of the membrane structure due to a given volume of ponding water. The monolithic methods involve simultaneously solving the structural equations and the fluid equations under static conditions, to obtain the structural deformation. The partitioned method on the other hand involves external coupling iterations involving a structural solver and volume conserving solver, where the volume conserving solver is responsible for updating the free surface to maintain a given volume of water. The discussed methods are compared in terms of robustness and computing time. It was found that the monolithic methods were computationally efficient. However, the partitioned method-apart from being modular-was found to be more robust with quasi-Newton convergence accelerators

Simulation of wind induced excitation of a membrane structure with ponding water

This paper proposes a new partitioned coupling approach to simulate the wind induced excitation of a membrane structure with ponding water. This approach uses three different solvers to simulate wind, water and membrane structure. The main assumption here is that the interaction between the wind and water can be neglected due to the small depth and small fetch of the water, relative to the size of the membrane structure. This assumption results in a coupling strategy where the structural solver independently interacts with the wind and water solver. The results from this method is compared with a straightforward approach, where a two-phase solver, modeling the wind and water, is coupled to a structural solver. The obtained results agreed very well with the reference modeling approach, where all the interactions are taken into account. Furthermore, the proposed method was found to be computationally more efficient