Reliability Characterization of a Piezoelectric Actuator Based AVC System

Author(s):  
Marco Mazzola ◽  
Francesco Aggogeri ◽  
Angelo Merlo ◽  
Bernhard Brunner ◽  
Maria de la O Rodriguez

Reliability and Maintainability analyses are becoming an increasing competitive advantage in machine tool design. In particular, the goal of machine tools for Ultra High Precision Machining is to guarantee high specified performances and to maintain them over life cycle time. A structured reliability approach applied to such complex and innovative systems must be integrated in the early phase of the design. In this paper, the reliability characterization of an adjustable platform for micromilling operations is presented. The platform is intended to improve the surface finishing of the workpiece, through a broadband Active Vibration Control device based on high performance piezoelectric multilayer actuators. The study intends to assess the capability of the system to maintain along the life cycle the appropriate reduction of the chattering vibrations without any shape error. By dividing the system through a morphological-functional decomposition, the critical elements are detected and their reliability issues are extensively discussed. Their lifetimes are described through opportune distributions and models. The study is completed by the quantitative reliability prediction of the overall system. Finally, a sensitivity analysis is performed and reliability allocation implications are evaluated to determine the effect of every component on the system reliability characteristics and life cycle cost.

2018 ◽  
Vol 25 (4) ◽  
pp. 748-762 ◽  
Author(s):  
A Khansefid ◽  
A Bakhshi

In this paper, an attempt is made to examine a new method for designing and applying the active vibration control system to improve building performance under mainshock–aftershock sequences. In this regard, three different structures are considered; 5-, 10-, and 15-story buildings. Seven mainshock–aftershock sequences are selected from the Iranian accelerogram database for analyzing the structures. By implementing an advanced two-step optimization method, buildings equipped with the active vibration control system (linear–quadratic regulator (LQR) algorithm) are designed to withstand all events of mainshock–aftershock sequences. In the first optimization step, a multi-objective optimization with the genetic algorithm is performed and a set of optimal Pareto front results is obtained. In the next step, the life-cycle cost of each optimal design sample of the Pareto front is calculated by considering the cumulative damage and the design sample with the minimum cost is selected as a final optimal property. The results prove that the active vibration control system is capable of reducing structural responses, including acceleration, drift, and residual drift under mainshock–aftershock sequences, and consequently the life-cycle cost of buildings, especially the taller ones. In addition, obtaining the building design variables (story stiffness and yielding force) and active LQR algorithm properties simultaneously leads to a slightly softer final building model than the conventional structure designed by the common building design code. Moreover, it is revealed that, by considering the aftershocks, the building life-cycle cost increases significantly.


2003 ◽  
Vol 30 (5) ◽  
pp. 841-849 ◽  
Author(s):  
Mostafa A Hassanain ◽  
Robert E Loov

Recent surveys have indicated that between 30% and 40% of all bridges in North America are in various states of deterioration. Funding is limited owing to the existence of other deficient components of the transportation infrastructure. It is clear, therefore, that the return on the available funding needs to be maximized. This paper presents a review of publications on cost optimization of concrete bridge components and systems and then continues with a review of the state-of-the-art in life-cycle cost (LCC) analysis and design of concrete bridges. The main objective of the paper is to encourage bridge engineers to move towards the increased use of advanced analysis and design optimization methods.Key words: bridge, concrete, cost, high-performance concrete, infrastructure, life-cycle cost, optimization, prestressed girders, reliability.


2017 ◽  
Vol 2639 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Mehdi Akbarian ◽  
Omar Swei ◽  
Randolph Kirchain ◽  
Jeremy Gregory

Life-cycle cost analysis (LCCA) is a commonly used approach by pavement engineers to compare the economic efficiency of alternative pavement design and maintenance strategies. Over the past two decades, the pavement community has augmented the LCCA framework used in practice by explicitly accounting for uncertainty in the decision-making process and incorporating life-cycle costs not only to the agency but also to the users of a facility. This study represents another step toward improving the LCCA process by focusing on methods to characterize the cost of relevant pay items for an LCCA as well as integrating costs accrued to users of a facility caused by pavement–vehicle interaction (PVI) and work zone delays. The developed model was implemented in a case study to quantify the potential implication of both of these components on the outcomes of an LCCA. Results from the construction cost analysis suggest that the proposed approaches in this paper lead to high-fidelity estimates that outperform current practice. Furthermore, results from the case study indicate that PVI can be a dominant contributor to total life-cycle costs and, therefore, should be incorporated in future LCCAs.


2007 ◽  
Vol 546-549 ◽  
pp. 2143-2150
Author(s):  
Cheng Bao Jiang ◽  
Li Hong Xu ◽  
Tian Li Zhang ◽  
Tian Yu Ma

Co and Si were selected as substitutes to improve performance of TbDyFe giant magnetostrictive alloys for special purpose, respectively. The results showed that the Co-doped Tb0.36Dy0.64Fe2 alloys can possess giant magnetostriction over a wide temperature range from -80 to 100 . Optimum magnetostriction, high electrical resistivity and improved corrosion resistance was obtained in Tb0.3Dy0.7(Fe1-xSix)1.95 system. High performance grain-aligned rods with <110> preferred orientation have been successfully prepared by zone melting unidirectional solidification. This paper also presents the design and fabrication of Giant Magnetostrictive Actuator (GMA) for active vibration control with oriented TbDyFe rods. Experimental results showed that the GMA possesses good static and dynamic performance. Excellent damping effect, 20-30 dB under the frequency range from 10 Hz to 120 Hz was obtained.


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