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Application of Inertial Sensors in Developing Smart Particles
Published in Krzysztof Iniewski, Smart Sensors for Industrial Applications, 2017
Ehad Akeila, Zoran Salcic, Akshya Swain
In the real environment, the SP is exposed to forces, which may cause to move the SP randomly inside water. These motions can be classified into two main types: (a) linear accelerations and (b) rotational motions. The following devices have been utilized to simulate each type of motion and calibrate the sensors as well as the whole system: Shake-table: This machine is generally used to simulate and test the effect of earthquakes on structures and buildings. The shake-table has a highly sensitive single axis accelerometer, which measures the accelerations generated by the table. Figure 32.10a shows the shake-table and the direction of motion produced by it. 2D rotational motors: This device was designed and built to generate rotational motions in two dimensions as shown in Figure 32.10b. It is manually controlled to rotate the SP at certain desired angles. The motors are then placed on the shake table such that linear accelerations are combined with rotational motions at the same time. Figure 32.10c shows the final setup.
Seismic Considerations
Published in John D. McDonald, Electric Power Substations Engineering, 2017
The previous discussion pertains to the structural performance of the equipment. Qualification by analysis provides no assurance of electrical function. Shake table testing provides assurance for only those electrical functions verified by electrical testing and only to the levels applied in the test. Shake table testing may be required for equipment that was qualified by dynamic analysis in accordance with other standards but performed poorly during past earthquakes. However, static or static-coefficient analysis may still be specified if past seismic performance of equipment qualified by such methods has consistently led to acceptable performance.
Combined Actuator-Shake Table Test with Optimized Input Energy
Published in Jian Zhang, Zhishen Wu, Mohammad Noori, Yong Li, Experimental Vibration Analysis for Civil Structures, 2020
Farhad Behnamfar, Mohammadreza Najar
Various methods for earthquake engineering tests have been developed in the recent decades, including the pseudo-static, pseudo-dynamic, shake table, and hybrid experimental methods. In the pseudo-static testing the specimen is deformed up to predefined values by the forces generated by hydraulic actuators. The applied forces and the produced deformations change slowly, and therefore the inertial and damping forces that are specific to the dynamic response are not accounted for in this type of testing. The main idea behind this method is to evaluate the hysteresis behavior of different structural members instead of structural systems [1]. In the pseudo-dynamic testing again the rate of loading on the model is slow but the inertial forces are simulated with the aid of a computer controlling the progress of the test. This method is usually used for testing structural systems that can be as large as a full-scale building. In this method the lateral displacements of stories are analytically calculated using time integration methods at each time step. Then the actuators push at different levels to their calculated lateral displacements, and the actuator forces required to produce the above displacements are directly recorded by the load cells. The story shear at each level is determined as the sum of its above lateral forces. The calculated shear forces are utilized in the nonlinear dynamic equations of the system, using which the lateral displacements for the next time step are calculated by the computer controlling the testing procedure. Since there is no need to apply forces at high speeds in this method, the experimental apparatus is simpler and cheaper; therefore larger and even full-scale models can be tested. However, the effects of inertial and viscous damping forces produced by rapid motions of system during earthquake is only taken into account analytically and cannot be generated in the physical part of the test [1]. Shake tables are known for their ability to simulate the dynamic loading precisely, but they are the most expensive testing machines that are limited in number and size around the world [1].
Advanced Control Strategy for Floor Response Replication of High-Rise Buildings Subjected to Earthquakes
Published in Journal of Earthquake Engineering, 2022
Seismic shake table testing has been widely adopted to investigate seismic responses of structures subjected to earthquake ground motions. Owing to the rapid development of software and hardware, the performance of seismic shake table has been improved significantly over the century since the first shake table was built in 1906 (Severn 2011). Nevertheless, it remains challenging to reproduce ground motions perfectly as the inherent dynamics of servo-hydraulic systems is highly nonlinear. The inherent dynamics could interact with the test structures, leading to the so-called control–structure interaction (CSI) (Dyke et al. 1995) which could distort the reproduced motion of shake tables (Trombetti and Conte 2002; Trombetti, Conte, and Durrani 1997). Furthermore, the oil-column resonance and the friction between each component could affect the controllability of shake tables (Muhlenkamp et al. 1997)
Seismic Performance Evaluation of Two-story Dhajji-dewari Traditional Structure
Published in International Journal of Architectural Heritage, 2021
Qaisar Ali, Naveed Ahmad, Muhammad Ashraf, Tom Schacher
One of the important aspects of shake table testing is to subject the models to shaking as nearly as possible to the natural ground shaking caused by actual earthquakes. Moreover, the input excitation should be such as to subject the model to the most critical earthquake loading. Peak ground acceleration, duration, and frequency content are the important parameters that determine the severity of an earthquake. Also, the size of the earthquake (i.e. magnitude) and the source tectonics (shallow or deep, active/stable, fault mechanism, etc.) should be compatible with the selected site. Based on these conditions, the north-south component of the 1995 Kobe shallow earthquake (Mw = 6.9, depth less than 20 km, strike-slip fault mechanism) record was selected. The fault focal mechanism of the selected earthquake is different than the case study site (Himalayan region), where most of the earthquakes are generated on faults with reverse or reverse-oblique mechanism. However, this record exhibits extreme loading for flexible/long period structures, therefore, it is appropriate for the selected test model. The Kobe record is original of 50 seconds duration but the first 30 seconds record was used in this study. To satisfy the similitude requirement of a simple model, the time duration of the Kobe record was compressed by a scale factor of 3 (Table 3).
Seismic qualification and time history shake-table testing of high voltage surge arrester under seismic qualification level moderate
Published in Cogent Engineering, 2018
Noman Ullah, Syed Mohammad Ali, Rahman Shahzad, Faisal Khan
Seismic qualification by time-history testing of the equipment using a shake table is a rigorous test method which is considered to provide clear evidence of the capability of equipment to withstand seismic forces. Seismic qualification by time-history testing can be divided into two steps; namely, (1) Resonant frequency test (Free vibration test), and (2) Time history shake-table testing.