Summary: The effect of blast-induced ground VIBRATIONs on mines and on adjacent structures and facilities is an example of the adverse consequences of the mining cycle. In order to control the VIBRATIONs, and also, managing the adverse effects, the measurement and modeling of the concerned wave ATTENUATION are necessary. Normally, by implementing several trial blasts and analyzing corresponding ground VIBRATIONs, we can determine the related ATTENUATION model for different sites and mines. Usually, the modeling of the peak particle velocity (PPV) damping is performed based on the distance between blast-face and monitoring station and maximum charge used per delay. In this research, using different empirical models, the PPV equation is determined for blasting in the Sungun copper mine. Moreover, imperialist competitive algorithm (ICA) has been employed to develop prediction model for ground VIBRATIONs. A comparison of the results obtained from different models are made based on several statistical tests between monitored and predicted values of PPV. According to these statistical tests, fairly good performance of the ICA-based model in the forecasting of PPV is proved. Introduction Drilling and blasting are typical methods of rock excavation. The ground VIBRATIONs are an adverse effect of blasting that cannot be completely eliminated; but certainly can be minimized up to permissible level to avoid possible damages to surrounding structures. Ground VIBRATION is directly related to the maximum charge per delay and distance between blast face and monitoring station. To predict ground VIBRATION, several empirical models have been developed by various investigators. In the most of these models, the PPV is the parameter of concern. Methodology and Approaches In this paper, the ICA was proposed to get an appropriate equation for forecasting the PPV in the Sungun copper mine. For comparison purposes, three well-known empirical models were also used. To evaluate the performance of PPV models, the correlation between the predicted and real measured values of PPV was determined. Standard statistical evaluation criteria were used to evaluate the performances of different PPV predictor models. Results and Conclusions Considering the calculated statistical error between the forecasted and real measured values of PPV, the ICA-based model has the lowest values of MAE, VARE and RMSE, while it has the highest value of VAF, in comparison with the empirical models.

The present article is an attempt at utilizing a feedback control system based on cylinder rotary oscillations in order to attenuate the two-degree-of-freedom VIBRATIONs of an elastically-supported square-section cylinder in presence of flow. The control system benefits from the cylinder rotational oscillations about its axis that acts according to lift coefficient feedback signal of the cylinder. Based on the performed numerical simulations, it becomes clear that the active control system has successfully mitigated the two-degree-of-freedom VIBRATIONs of square cylinder both in the lock-in region and galloping zone. For a Reynolds number of Re = 90 located in the lock-in region, the active rotary oscillating (ARO) controller has achieved a 98% reduction in the cylinder transverse VIBRATION amplitude, while the corresponding value for the in-line VIBRATION is 88%. Moreover, for a Reynolds number of Re = 250 in the galloping zone, the ARO controller has successfully attenuated the cylinder transverse VIBRATION amplitude by 72%, while the same value for the in-line VIBRATION is 70%. One also observes that the ARO controller decreases the amplitude of lift and drag coefficients in the lock-in region by, respectively, 95% and 94%. In contrast, the corresponding percentages for the cylinder in the galloping zone are 24% and 39%, respectively.

Successful implementation of active control technology requires an appropriate control algorithm to calculate the adaptive control force required by the actuators. Smart structures represent a new engineering approach that integrates the actions of digital sensors, actuators and control circuit elements into a single control system that can respond adaptively to environmental stochastic changes in a useful manner. The mathematical model of the system is an estimation of its actual dynamic behavior. In general, this difference can have a significant effect on the performance and stability of the control system. One of the important issues in active control algorithms is the evaluation of the control system's robustness to model uncertainties and the actuator saturation. In this paper, a Developed Robust Proportional Integral Derivative controller with uncertainties in the structural stiffness parameter, the sensing noise and saturation windup of the saturation is introduced. the PID control force is obtained in such a way that the infinity norm of the closed loop system transfer function from disturbance inputs to target outputs becomes minimal. By considering the parametric uncertainty in the structural stiffness parameters and multiplicative unstructured uncertainty and the windup phenomenon in the actuator model and existence of noise in the velocity sensor, PID control scheme has been developed in the form of state space. The PID control gains by taking advantage of the H∞,mixed sensitivity minimization criterion, are obtained simultaneously by considering the effects of all VIBRATION modes of the building in such a way that the infinity norm of the closed loop transfer function from exogenous inputs to the controlled outputs becomes minimal. To demonstrate the robust performance and stability of the proposed algorithm, the results of numerical simulations on a 4-story structure equipped with an active tuned mass damper are used. The obtained results show the robust performance and stability of the proposed robust PID control scheme in comparison with conventional PID and linear quadratic regulator (LQR) control algorithms, both in time and frequency domains. According to the mean values of performance indices, in average 11 and 7% more reduction in J1, 7 and 5% in J2 and 10 and 6% in J3 in the proposed robust PID in comparison with the LQR and common PID for three models subjected to far field selected earthquake records. And in average 17 and 10% more reduction in J1, 12 and 8% in J2 and 11 and 8% in J3 in the proposed robust PID in comparison with the LQR and common PID for three models subjected to near field selected earthquake records. And J4 which related to amount of control effort, for the proposed robust PID, LQR and conventional PID are 1. 3e-2, 9. 1e-3 and 7. 9e-3 in average for the three models subjected to far field and 4e-2, 2. 4e-2 and 2. 7e-2 subjected to near field selected earthquake records. The obtained results show the robust performance and stability of the proposed controller in the presence of structural stiffness uncertainties, actuator saturation and measurement noise.

Introduction: Delayed onset muscle soreness (DOMS), which occurs after eccentric exercises, may cause some reduction in ability in sport activities. For this reason, numerous recovery strategies have been used in an attempt to control the inflammatory-type response. Physical modalities have demonstrated no effect on the alleviation of muscle soreness or other DOMS symptoms. Whole-body VIBRATION (WBV) has been suggested as a viable warm-up in sport fields. However, there is a lack of scientific evidence to support the protective effects of WBV-Training (WBVT) on muscle damage.Material and Methods: Thirty-two healthy untrained volunteers randomly assigned into two groups: WBVT (n=15) and control (n=17). Subjects performed 6 sets of 10 maximal isokinetic (60°.s-1) eccentric contractions of knee extensors with dominant limb on a dynamometer. In the WBVT group before eccentric exercise, whole body VIBRATION was applied using a vibratory platform (Power Plate, 35 Hz, 5 mm peak-topeak amplitude), with 100° knee flexion for 60 seconds while no VIBRATION was applied in the control group. DOMS criteria (serum creatine kinase (CK), pressure pain threshold (PPT), muscle soreness, thigh circumference and maximal voluntary isometric exertion) were recorded at baseline, immediately after, 1to 14 days postexercise.Results: WBVT group showed significant reduction of DOMS symptoms in terms of lower CK levels, less PPT, less muscle soreness and lower maximal isometric voluntary strength loss compared to the control group (P<0.05) However, no significant effect on thigh circumference was evident (P>0.05).Conclusions: The findings of this study showed that WBVT administered before eccentric exercise may control and prevent DOMS and enhance the quadriceps muscle activity. Further investigation should be undertaken to ascertain the effectiveness of WBVT in athletes.

This study focuses on the investigation of intelligent form-finding and VIBRATION analysis of a triangular polyhedral tensegrity that is enclosed within a sphere and subjected to external loads. The nonlinear dynamic equations of the system are derived using the Lagrangian approach and the finite element method. The proposed form-finding approach, which is based on a basic genetic algorithm, can determine regular or irregular tensegrity shapes without dimensional constraints. Stable tensegrity structures are generated from random configurations and based on defined constraints (nodes located on the sphere, parallelism, and area of upper and lower surfaces), and shape finding is performed using the fitness function of the genetic algorithm and multi-objective optimization goals. The genetic algorithm's efficacy in determining the shape of structures with unpredictable configurations is evaluated in two distinct scenarios: one involving a known connection matrix and the other involving fixed or random member positions (struts and cables). The shapes obtained from the algorithm suggested in this study are validated using the force density approach, and their VIBRATION characteristics are examined. The findings of the comparative study demonstrate the efficacy of the proposed methodology in determining the VIBRATIONal behavior of tensegrity structures through the utilization of intelligent shape seeking techniques.

This paper investigates the influence of temperature on the active VIBRATION control of laminated composite cantilever beams using collocative experimental and simulation techniques. The system identification toolbox of the MATLAB simulation tool is utilized to obtain the transfer function of the plant model. The adequate VIBRATION ATTENUATION of the glass-epoxy cantilever beam operating in various thermal environments is achieved using the proportional (P) and proportional-integral-derivative (PID) controllers. The VIBRATION ATTENUATION characteristics of the developed control algorithms are comprehensively investigated for a wide temperature range of –20 °C to 60 °C using PZT-5H patches. Particular emphasis is given to the VIBRATION control of the fundamental natural frequency of the laminated composite cantilever beam. The obtained results of open and closed-loop models are presented in both time and frequency domains. The results indicate that for all the temperatures considered, the PID controller is found to be more effective in VIBRATION ATTENUATION than the P controller. The VIBRATION ATTENUATION performance of the cantilever beam considerably improved at the higher magnitude of temperature values. The natural frequency of the system is reduced continuously with an increase in temperature.

Helicopters can be a source of loud noise. The high production noise of helicopters makes them unsuitable for densely populated areas, especially in low-flying conditions. This study examines methods and offers solutions to reduce or eliminate the noise produced by helicopters. Several methods have been considered to reduce the noise produced. Solutions such as muffler for motors, use of modulated blade spacing, X-force control, reduced tip speed, blade tip modification, airfoil tailoring, Increasing the number of main rotor blades, active blade control and variable diameter rotor in The rotor and the use of the strut in the gearbox were introduced. According to the studies conducted in the present study, combined methods haveas the best noise reduction. although Independent methods reduce noise, depending on the amount of reduction required in the targeting, combining the methods can be achieved the appropriate answer.