以PhysX模擬作用於結構物之風負載

Abstract

In designing structures, civil / structural engineers need to make sure that the structure will be able to withstand major loading that will happened during the service life of the structure, either due to static / dead loading as well as live loading. On live loading, this kind of loading can due to occupancy of structures, earthquake, wind, machine loading, etc. Up to now, there are some well-known and acceptable methods to approximate wind loading on structures, they are: (1) the approximating wind loading equations provided at many building codes, (2) wind tunnel simulation testing for relatively complex or uncommon structures, (3) CFD (Computational Fluid Dynamics) simulation. Here in this thesis we consider another possibility of approximating wind loading on structures, that is using physics engine, and in this thesis we consider particularly PhysX physics engine. The PhysX Physics Engine used in this research work is the PhysX version 3.1, and the work will be based on the PhysX 3.1 SDK [3]. For doing so, we consider how well PhysX physics engine simulate wind loading on simple objects, and here in this research we consider simulation of wind loading on a cylinder shaped structure as well as box shaped structure, both of them having diameter / side dimension of 10 meters. As the framework of the simulation, we create a virtual wind tunnel having dimension of 40 meter by 40 meter for the cross section, and having length of 120 meters, and the number of particles used for simulating wind loading on these two simple structures are one million particles. While PhysX can make use of CPU or GPU (currently only NVidia GPUs are supported by NVidia) for computing power resources, due to higher computational performance of GPU compared to CPU, in this research we make use of GPU as the computational resource, and the GPU used in this simulation is a notebook-based GPU, the nVidia GT 240M, with memory of 1GB. We investigate how well the PhysX physics engine is to simulate the real world condition approximated by either fluid mechanics or Building Code. We found out that PhysX is capable of predicting wind loading on structure quite satisfactorily. We wish that this research result will be beneficial in considering how physics engine, particularly PhysX can be considered for a method in approximating wind loading on structures, and its usability in civil engineering.