The objective of this product is to address the specific need for improvements in the efficiency and effectiveness in physical separation technologies in the screening areas. Currently, the mining industry uses approximately 33 billion kW-hr per year, costing 1.65 billion dollars at 0.05 cents per kW-hr, of electrical energy for physical separations. Even though screening and size separations are not the single most energy intensive process in the mining industry, they are often the major bottleneck in the whole process. Improvements to this area offer tremendous potential in both energy savings and production improvements. Additionally, the vibrating screens used in the mining processing plants are the most costly areas from maintenance and worker health and safety point of views. The goal of this product is to reduce energy use in the screening and total processing areas. This goal is accomplished by developing an innovative screening machine based on smart materials and smart actuators, namely smart screen that uses advanced sensory system to continuously monitor the screening process and make appropriate adjustments to improve production. The theory behind the development of Smart Screen technology is based on two key technologies, namely smart actuators and smart Energy Flow ControlT (EFCT) strategies, developed initially for military applications. Smart Screen technology controls the flow of vibration energy and confines it to the screen rather than shaking much of the mass that makes up the conventional vibratory screening machine. Consequently, Smart Screens eliminates and downsizes many of the structural components associated with conventional vibratory screening machines. As a result, the surface area of the screen increases for a given envelope. This increase in usable screening surface area extends the life of the screens, reduces required maintenance by reducing the frequency of screen change-outs and improves throughput or productivity.
KEYWORDS: Systems modeling, Vibration control, Weapons, Control systems, Interfaces, Voltage controlled current source, Chemical elements, Software development, Actuators, Electronics
The work reported in this paper is focused on an effective and efficient solution, namely Smart Isolation Mount for Army Guns (SIMAG), to the weapon stabilization and fire control issues facing US Army guns. SIMAG is composed of the optimum integration of two innovative technologies. Vibration Control by Confinement and smart senor/actuator/active control systems. The combined approach may also be applied to a gun barrel to reduce its undesired vibratory motions excited by external and internal disturbances, such as gun firing action. SIMAG reconfigures the distribution and propagation of excess vibration energy and confines vibrations to certain non-critical regions or modes within a structure. Concentrated passive, active, or smart damping elements or cancellation techniques may be applied to more effectively dissipate or cancel the trapped vibrations and to prevent build up in the assembly. As the active elements, an array of collocated, PZT-based sensor- actuator sets is recommended for incorporation in SIMAG. Part of the active elements is used for spatially managing excess vibration energy while the other part is utilized for energy dissipation and cancellation. The preliminary result of our feasibility work on the SIMAG concept is demonstrated via computer simulations. It is shown that the insertion of a preliminary version of SIMAG in a 30mm gun system onboard an attack helicopter reduces the fluctuating loads and deformations measured across the helicopter bottom shell by 40 to 50 percent. SIMAG makes significant progress towards solving the firing control problems with affordable weight and power penalties by compensating for all errors in one of the two places, the turret-aircraft interface or gun barrel. Even thought the initial target application of SIMAG is airborne guns, a modified version can be incorporated into ground armors, such as tanks and humvees.
The purpose of this paper is to present the preliminary experimental results on the influence of vibration confinement on the optimization of sensor and actuator placement in smart structures. Previous studies have indicated that vibration confinement may have significant effects on the optimal location of sensors and actuators. Three types of structures, beam, plate, and cylinder structures, are examined in this paper. Two criteria based on an observability/controllability measure and actuator power requirements are used to evaluate the sensor/actuator performance. Based on our experimental results, it is clear that confinement has a significant impact on the optimization of sensors and actuators.
KEYWORDS: Voltage controlled current source, Vibration control, Absorption, Optical isolators, Active vibration control, Vibration isolation, Reliability, Manufacturing, Control systems, Interfaces
In this paper, an innovative vibration control method based on a combination of Vibration Control by Confinement and conventional isolation, absorption, and damping techniques is presented. First, the vibration energy is confined to selected parts of a structure resulting in low- and high-energy regions. Second, isolation, absorption, and damping techniques are utilized to control or dissipate the trapped energy within the high-energy areas. The effectiveness of the combined approach is examined by considering the vibration suppression of a system composed of a critical component resting on its supporting structure. The commonly used vibration control methods are combined with the confinement approach and compared to a set of baseline results. Our preliminary results show that the combination of the confinement technique and conventional vibration suppression methods is effective over the frequency range of interest. It is pointed out that the proposed approach is a practical method to overcome some of the challenges of the current passive and active vibration control techniques.
KEYWORDS: Sensors, Actuators, Control systems, Vibration control, Sensor performance, Control systems design, Lab on a chip, Smart structures, Feedback control, Image segmentation
The objective of this work is twofold. First, the influence of confined vibrations on the sensor and actuator optimization is determined and evaluated. Second, a preliminary design methodology to incorporate confined vibration response in the design stage of the sensor/actuator arrays used in smart structures is introduced. In this paper, the influence of confinement on the performance and optimal location of the sensor/actuator sets is evaluated based on two different optimization criteria. The first criterion is based on a specified performance index related to the observability and controllability grammians of the sensors and actuators, respectively. The second criterion is based on the energy dissipated through collocated sensor/actuator sets. Three types of structural components, beam, plate, and cylinder, are evaluated. Theoretical results are verified by laboratory tests conducted on all three structural components. The preliminary results of this work clearly show that vibrational confinement has a significant effect on the performance and position optimization of sensors and actuators. The proposed modified optimization procedure and design methodology are proven to be effective in addressing certain issues. It is concluded that the unintentional occurrence of confined vibrations may be detrimental to vibration control systems. On the other hand, one may take advantage of the intentional presence of confined vibrations in a structure to reduce the error in the optimal locations of sensors and actuators and optimize their performance by focusing the control effort on the confined areas.
In this paper, the results of a feasibility study for developing an efficient and effective design methodology to make systems 'smart by design' is presented. The primary focus is on computer-aided structural design to implement the inter-coupling of modes of vibration and smart devices built in the original design of structures. The conventional add-on elements are replaced by built-in multi tasks components. First, structures are designed so that a major portion of their vibration energy is localized into their non- critical areas and thereby isolate and quieten critical areas. Next, multi tasks smart components are integrated in the most critical locations of the system in order to monitor and maintain the designed vibration characteristics of the system.
There exists a need to have a reliable comprehensive software/hardware to monitor the condition of airframe structures and aircraft components. Failure of any structural parts of aircraft are often prohibitively costly and could even lead to loss of life. The existing technologies deal with the use of some of the characteristics of structural vibration and thus resulting in false detections. The use of complete vibration signature measured by an array of embedded (or attached) fiber-optic sensors, which are loaded with multiple laser beams generated by a single optical source, is the focus of this project. The hardware will be light weight, low cost, and effective for monitoring discontinuities, damage, and delamination in both composite and metal airframes.
KEYWORDS: Interfaces, Vibrometry, Mathematical modeling, Finite element methods, Matrices, Control systems, Smart structures, Chemical elements, Computer simulations, Vibration control
To actively and intelligently control the elastic motions of structures, smart devices (sensors and actuators) need to be attached to or embedded in structural components. In this article an effective semi-numerical approach for mathematical modeling of interfaces between the host structure and smart devices is proposed. The model is based on the component-mode syntheses via receptance method which is most suitable for vibration analysis and control. By utilizing the receptance method, large mass and stiffness matrices of the conventional finite element models are replaced by natural frequencies and mode shapes of the host structure and those of the attached or embedded elements. Three types of interfaces are investigated: point, line, and surface interfaces. Contrary to conventional methods, the line and surfaces are modeled as actual lines and surfaces rather than a finite number of points. The latter, drastically reduces the degrees of freedom and significantly improves the accuracy of the numerical values. Finally, such formulation results in a huge reduction in the size of the model and tremendous gain in computational speed.
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