Smart FRP Composite Sandwich Bridge Decks in Cold Regions

INE/AUTC 12.0

Novel Structural Health Monitoring and Damage Detection Approaches for Composite and Metallic Structures

Mechanical durability of the structures should be continuously monitored during their operation. Structural health monitoring (SHM) techniques are typically used for gathering the information which can be used for evaluating the current condition of a structure regarding the existence, location, and severity of the damage. Damage can occur in a structure after long-term operating under service loads or due to incidents. By detection of these defects at the early stages of their growth and nucleation, it would be possible to not only improve the safety of the structure but also reduce the operating costs. The main goal of this dissertation is to develop a reliable and cost-effective SHM system for inspection of composite and metallic structures. The Surface Response to Excitation (SuRE) method is one of the SHM approaches that was developed at the FIU mechatronics lab as an alternative for the electromechanical impedance method to reduce the cost and size of the equipment. In this study, firstly, the performance of the SuRE method was evaluated when the conventional piezoelectric elements and scanning laser vibrometer were used as the contact and non-contact sensors, respectively, for monitoring the presence of loads on the surface. Then, the application of the SuRE method for the characterization vii of the milling operation for identical aluminum plates was investigated. Also, in order to eliminate the need for a priori knowledge of the characteristics of the structure, some advanced signal processing techniques were introduced. In the next step, the heterodyne method was proposed, as a nonlinear baseline free, SHM approach for identification of the debonded region and evaluation of the strength of composite bonds. Finally, the experimental results for both methods were validated via a finite element software. The experimental results for both SuRE and heterodyning method showed that these methods can be considered as promising linear and nonlinear SHM approaches for monitoring the health of composite and metallic structures. In addition, by validating the experimental results using FEM, the path for further improvement of these methods in future researches was paved

Recursive partitioning and Gaussian Process Regression for the detection and localization of damages in pultruded Glass Fiber Reinforced Polymer material

In this paper, a methodology for the detection and localization of damages in composite pultruded members is proposed. This is particularly relevant to thin-walled pultruded members, which are typically characterized by orthotropic behavior, anisotropic along the fibers and isotropic in the cross section. Hence, a method to detect and localize damage, and the influence these might have on the performance of thin-walled Glass Fiber Reinforced Polymer (GFRP) members, is proposed and applied to both numerical and experimental data. Specifically, the numerical and experimental modal shapes of a narrow flange pultruded profile are analyzed. The reliability of the proposed semiparametric statistical method, which is based on Gaussian Processes Regression and Bayesian-based Recursive Partitioning, is analyzed on a narrow flange profile, artificially affected by sawed notches with incremental depth. The numerical investigation is carried out via finite element models (FEMs) of the cracked beam, where the dynamic parameters and the modal shapes are computed. In total, three different crack sizes are investigated, to compare the results with the experimental ones. Finally, the proposed approach is further extended and validated on numerically simulated frame structures

Structural Health Monitoring of Large Structures Using Acoustic Emission-Case Histories

Acoustic emission (AE) techniques have successfully been used for assuring the structural integrity of large rocket motorcases since 1963 [...

Activities of the Center for Space Construction

The Center for Space Construction (CSC) at the University of Colorado at Boulder is one of eight University Space Engineering Research Centers established by NASA in 1988. The mission of the center is to conduct research into space technology and to directly contribute to space engineering education. The center reports to the Department of Aerospace Engineering Sciences and resides in the College of Engineering and Applied Science. The college has a long and successful track record of cultivating multi-disciplinary research and education programs. The Center for Space Construction is prominent evidence of this record. At the inception of CSC, the center was primarily founded on the need for research on in-space construction of large space systems like space stations and interplanetary space vehicles. The scope of CSC's research has now evolved to include the design and construction of all spacecraft, large and small. Within this broadened scope, our research projects seek to impact the underlying technological basis for such spacecraft as remote sensing satellites, communication satellites, and other special purpose spacecraft, as well as the technological basis for large space platforms. The center's research focuses on three areas: spacecraft structures, spacecraft operations and control, and regolith and surface systems. In the area of spacecraft structures, our current emphasis is on concepts and modeling of deployable structures, analysis of inflatable structures, structural damage detection algorithms, and composite materials for lightweight structures. In the area of spacecraft operations and control, we are continuing our previous efforts in process control of in-orbit structural assembly. In addition, we have begun two new efforts in formal approach to spacecraft flight software systems design and adaptive attitude control systems. In the area of regolith and surface systems, we are continuing the work of characterizing the physical properties of lunar regolith, and we are at work on a project on path planning for planetary surface rovers

Aircraft electrical power system diagnostics, prognostics and health management

In recent years, the loads needing electrical power in military aircraft and civil jet keep increasing, this put huge pressure on the electrical power system (EPS). As EPS becomes more powerful and complex, its reliability and maintenance becomes difficult problems to designers, manufacturers and customers. To improve the mission reliability and reduce life cycle cost, the EPS needs health management. This thesis developed a set of generic health management methods for the EPS, which can monitor system status; diagnose faults/failures in component level correctly and predict impending faults/failures exactly and predict remaining useful life of critical components precisely. The writer compared a few diagnostic and prognostic approaches in detail, and then found suitable ones for EPS. Then the major components and key parameters needed to be monitored are obtained, after function hazard analysis and failure modes effects analysis of EPS. A diagnostic process is applied to EPS using Dynamic Case-based Reasoning approach, whilst hybrid prognostic methods are suggested to the system. After that, Diagnostic, Prognostic and Health Management architecture of EPS is built up in system level based on diagnostic and prognostic process. Finally, qualitative evaluations of DPHM explain given. This research is an extension of group design project (GDP) work, the GDP report is arranged in the Appendix A

Ehs Risk Assesment of M.R.C.S.B Project, L&T, Goa (Under Construction) and Design of City Gas Distribution Network by Using Technical Standards and Specification Including Safety Standards

An EHS leader must Fully understand the philosophy of L.I.F.E. & Zero Harm Vision along with Inspire others to behave safely and have due regard for the environment. He must have ability to recognize the connection between good EHS and good business practices and Posses up-to-date EHS knowledge. He must have communication skills to convey and demonstrate leadership to all levels of the workforce and committed to action at all times. EHS culture has four stages namely pathological, reactive, calculative, proactive and generative stage. Zero harm vision has seven key elements. First element is leadership and commitment so Leaders must promote & demonstrate visual EHS commitment, excellence and lead by example. Second element is the risk management. Class one risk activity incorporated with working at height, vehicles, plants and equipment, tunneling, excavation, form work, mechanical lifting, work in confined space, work with electricity, working adjacent to public areas and hot work. Third element is setting of objectives and targets which should be measurable, attainable, and relevant and must have time bound. Fourth element is training and competence which includes of evaluation of training needs and periodical training for all personnel. Daily tool box talk to create awareness and propagate the incident and case studies among all the workmen. Fifth element is the communication and consultation. It includes monthly EHS meeting, EHS notice board, and EHS newsletter. Sixth element is to measure performance by inspection, internal audit and external audit. Seventh element is review and changes. Reviewing & managing changes is designed to expedite control and manage changes to policies, procedures, standards, organizational management and the execution or sequence of EHS related critical activities. Risk management has four stages namely identifying hazards, access the risk, determine the controls, and implement the controls, monitor, review and update. The approach must passes through a hierarchy of elimination, substitution, engineering control, administrative control, training and Personal protective equipment. In this study I have done risk assessment of different activities of construction of MRCSB Project, L&T, Goa. Then a comparable study between RA and RR has been done. After analyzing all the facts it is found that despite Risk assessment for every activities the KPI are not up to expectation. So to find out the root cause of this nonconformity gap analysis has been done. Real field data collected along with lagging and leading indicator, discussion with ground people. Fish bone analysis and by studying different laws, code of practices suggest some recommendation to improve site condition

Novel Approaches for Structural Health Monitoring

The thirty-plus years of progress in the field of structural health monitoring (SHM) have left a paramount impact on our everyday lives. Be it for the monitoring of fixed- and rotary-wing aircrafts, for the preservation of the cultural and architectural heritage, or for the predictive maintenance of long-span bridges or wind farms, SHM has shaped the framework of many engineering fields. Given the current state of quantitative and principled methodologies, it is nowadays possible to rapidly and consistently evaluate the structural safety of industrial machines, modern concrete buildings, historical masonry complexes, etc., to test their capability and to serve their intended purpose. However, old unsolved problematics as well as new challenges exist. Furthermore, unprecedented conditions, such as stricter safety requirements and ageing civil infrastructure, pose new challenges for confrontation. Therefore, this Special Issue gathers the main contributions of academics and practitioners in civil, aerospace, and mechanical engineering to provide a common ground for structural health monitoring in dealing with old and new aspects of this ever-growing research field

Vestas V90-3MW Wind Turbine Gearbox Health Assessment Using a Vibration-Based Condition Monitoring System

Reliable monitoring for the early fault diagnosis of gearbox faults is of great concern for the wind industry.This paper presents a novel approach for health condition monitoring (CM) and fault diagnosis in wind turbine gearboxes using vibration analysis. This methodology is based on amachine learning algorithm that generates a baseline for the identification of deviations fromthe normal operation conditions of the turbine and the intrinsic characteristic-scale decomposition (ICD) method for fault type recognition. Outliers picked up during the baseline stage are decomposed by the ICD method to obtain the product components which reveal the fault information.The new methodology proposed for gear and bearing defect identification was validated by laboratory and field trials, comparing well with the methods reviewed in the literature

NASA Automated Rendezvous and Capture Review. Executive summary

In support of the Cargo Transfer Vehicle (CTV) Definition Studies in FY-92, the Advanced Program Development division of the Office of Space Flight at NASA Headquarters conducted an evaluation and review of the United States capabilities and state-of-the-art in Automated Rendezvous and Capture (AR&C). This review was held in Williamsburg, Virginia on 19-21 Nov. 1991 and included over 120 attendees from U.S. government organizations, industries, and universities. One hundred abstracts were submitted to the organizing committee for consideration. Forty-two were selected for presentation. The review was structured to include five technical sessions. Forty-two papers addressed topics in the five categories below: (1) hardware systems and components; (2) software systems; (3) integrated systems; (4) operations; and (5) supporting infrastructure