Survivability of Suddenly Loaded Arrays of Micropillars

When a multicomponent system is suddenly loaded, its capability of bearing the load depends not only on the strength of components but also on how a load released by a failed component is distributed among the remaining intact ones. Specifically, we consider an array of pillars which are located on a flat substrate and subjected to an impulsive and compressive load. Immediately after the loading, the pillars whose strengths are below the load magnitude crash. Then, loads released by these crashed pillars are transferred to and assimilated by the intact ones according to a load-sharing rule which reflects the mechanical properties of the pillars and the substrate. A sequence of bursts involving crashes and load transfers either destroys all the pillars or drives the array to a stable configuration when a smaller number of pillars sustain the applied load. By employing a fibre bundle model framework, we numerically study how the array integrity depends on sudden loading amplitudes, randomly distributed pillar strength thresholds and varying ranges of load transfer. Based on the simulation, we estimate the survivability of arrays of pillars defined as the probability of sustaining the applied load despite numerous damaged pillars. It is found that the resulting survival functions are accurately fitted by the family of complementary cumulative skew-normal distributions.

PLANNING OF EXPERIMENTAL STUDIES OF THE "FOUNDATION-BASE" SYSTEM IN CASE OF SUDDEN OVERLOADS

The relevance of experimental and theoretical studies of the work of the foundation-foundation system in sudden burdens is justified. It was established that sudden loads can occur both in emergency situations and in the course of normal operation. The main criterion of sudden loading is the rate of additional or main (operational) loading, which is higher than the rate of stress redistribution in the base. In order to identify the main features of the foundation-foundation system and plan further studies, the results of preliminary experiments of the interaction of foundations with the soil base during sudden loads were analyzed. The accepted method of experimental research is described, the characteristics of the models of foundations and the power system used for testing are given. Some features of "foundation-soil" system operation in case of sudden loading are defined. Based on the conducted experiments, the need for further study of the foundation-foundation system in case of sudden loading was substantiated and the experiments were planned.

The Influence of Load Handling Height on Shoulder Biomechanics during Sudden Loading

Shoulder disorders have been reported as the most severe musculoskeletal disorders among all body parts. Multiple occupational risk factors such as manual material handling, repetitive motion, overexertion, fatigue, and overhead tasks have been reported to be associated with the development of shoulder disorders. The objective of this study was to investigate the effect of height (low, middle, high) on shoulder muscles during sudden loading. Kinematics and Electromyography (EMG) was recorded from 14 male participants. Effect of height found to be significant on normalized EMG and load travel distance. Bilateral shoulder muscles indicated higher NEMG with the increase of the load’s altitude. This increase of muscle activity could have resulted from the greater potential energy of the load at higher altitudes which required extra muscle activity to maintain the biomechanical stability of the shoulder. Reduced stability of shoulder at higher altitudes caused proprioceptive deficit which resulted in higher load travel distance.

A Novel Hybrid Particle Swarm- Multiverse Optimization based Voltage Stability Improvement in IEEE 57 Bus System

The major role of power system is voltage stability. It is required to plan properly and smooth operation and control. It presents a new approach of voltage stability improvement in IEEE 57 bus system using hybrid algorithm. The hybrid algorithm (PSO-MVO) is combination of PSO which is used for exploitation and MVO used for exploration. It is used in an uncertain environment. The FACTS device as STATCOM is connected in IEEE 57 test system to check for event of voltage stability improvement through power system analysis tool (PSAT) software. Once the ability of system goes through sudden loading, its stability gets affected. It desires compensation to boost voltage from disturbances. The varied operative condition while not used STATCOM in the system, used with STATCOM tuned by PSO-MVO algorithm are measured judge the performance of the projected system. The hybrid PSO-MVO technique is implemented in this paper to solve the proposed problem. The simulation results are obtained by PSAT software for 57 IEEE bus systems. The hybrid algorithm validates its effectiveness compare to individual PSO and MVO algorithm.