Various seismic and wind engineering designs and retrofit strategies have been in development to meet structures' proper and safe operation during earthquake and wind excitation. One such method is the addition of fluid and particle dampers, such as sand dampers, in an eort to reduce excessive and dangerous displacements of structures. The present study implements the discrete element method (DEM) to assess the performance of a pressurized sand damper (PSD) and characterize the dissipated energy under cyclic loading. The idea of a PSD is to exploit the increase in shearing resistance of sand under external pressure and the associated ability to dissipate energy through interparticle contact sliding. The dissipated energy in the pressurized sand during cyclic motion results in a reduction of excessive displacement. The advantage of using the DEM is that applying a simple linear contact model for the entire contacts assembly and also utilizing the advantage of irregular-shaped particles to mimic the behavior of actual sand grains. The series of DEM simulations reported herein examine the effects of multiple factors on the magnitude of dissipated energy. These factors include stroke amplitude, grain size distribution, the magnitude of pressure imposed on the sand, and different configurations of the PSD.
The results reveal that the main energy dissipation mechanism is generated through interparticle frictional sliding in the sand. Additionally, the magnitude of cumulative dissipated energy increases with the pressure level applied to the sand damper, as well as with the stroke amplitude of the loading. Moreover, operating the piston with multiple spheres leads to a significant increase in the magnitude of dissipated energy. However, the soil exhibits similar behavior to the case of one sphere where a strain hardening behavior was noticed. A noticeable increase in the piston capacity was observed when the sphere size was increased by 10%, and the rest of the response patterns remained unchanged. According to the results, by increasing the sphere friction, the piston capacity remains almost the same. It is also worth mentioning that when a wider range of particle sizes was employed, the capacity of the maximum force considerably increased. A significant increase in the piston capacity was clearly noticed when a boxed-shaped piston configuration was utilized at the origin of the pressurized sand damper instead of a single sphere.
The results of the conducted simulations were quantitatively compared with experimental data obtained from physical modeling of a similar pressurized sand damper which revealed a fairly good agreement. This confirms the ability of the proposed framework to satisfactorily analyze complex geotechnical problems involving soil interaction and large deformations. The proposed sand damper model is shown to be a promising device that mitigates vibrations in structural systems subject to seismic and wind loading.
Civil and Environmental Engineering
Usama El Shamy
Civil Engineering, Engineering, General/Other, Industrial/Manufacturing Engineering, Mechanical Engineering
Number of Pages
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
Sabi, Ehab, "ENERGY DISSIPATION IN A SAND DAMPER UNDER CYCLIC LOADING" (2022). Civil and Environmental Engineering Theses and Dissertations. 22.
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