scholarly journals Real-Time Life-Cycle Monitoring of Composite Structures Using Piezoelectric-Fiber Hybrid Sensor Network

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8213
Author(s):  
Yinghong Yu ◽  
Xiao Liu ◽  
Jiajia Yan ◽  
Yishou Wang ◽  
Xinlin Qing

In this paper, an in situ piezoelectric-fiber hybrid sensor network was developed to monitor the life-cycle of carbon fiber-reinforced plastics (CFRPs), from the manufacturing phase to the life in service. The piezoelectric lead-zirconate titanate (PZT) sensors were inserted inside the composite structures during the manufacturing process to monitor important curing parameters, including the storage modulus of resin and the progress of the reaction (POR). The strain that is related to the storage modulus and the state of resin was measured by embedded fiber Bragg grating (FBG) sensors, and the gelation moment identified by the FBG sensors was very close to those determined by dynamic mechanical analysis (DMA) and POR. After curing, experiments were conducted on the fabricated CFRP specimen to investigate the damage identification capability of the embedded piezoelectric sensor network. Furthermore, a modified probability diagnostic imaging (PDI) algorithm with a dynamically adaptive shape factor and fusion frequency was proposed to indicate the damage location in the tested sample and to greatly improve the position precision. The experimental results demonstrated that the average relative distance error (RDE) of the modified PDI method was 68.48% and 46.97% lower than those of the conventional PDI method and the PDI method, respectively, with an averaged shape factor and fusion frequency, indicating the effectiveness and applicability of the proposed damage imaging method. It is obvious that the whole life-cycle of CFRPs can be effectively monitored by the piezoelectric-fiber hybrid sensor network.

Author(s):  
yinghong yu ◽  
Xiao Liu ◽  
jun li ◽  
Yishou Wang ◽  
xinlin qing

Abstract The vacuum-assisted resin infusion (VARI) technique provides considerable advantages in manufacturing large-scale composite structures. An accurate and consecutive structural health monitoring system is urgently required to determine the initial quality and assess the structural integrity of a composite structure. In this paper, a real-time active smart diagnostic system (SDS) based on piezoelectric sensor network is proposed to monitor the whole life-cycle of composite structures. Experiments were conducted on carbon fiber reinforced plastic (CFRP) specimens with different thicknesses to investigate the monitoring capability of piezoelectric lead-zirconate-titanate (PZT) sensors used in the SDS approach. The PZT sensor networks inserted inside the composite structures during the VARI process are used to monitor not only the curing parameters, but also the health status of composite structures when they are in service after curing. To monitor the curing process only, the sensor network can also be installed on the bottom of the mould. Experimental results demonstrate that both three-dimensional resin flow and degree of cure (DOC) in the VARI process can be effectively monitored by the PZT sensor network. Meanwhile, the embedded PZT sensor network has the potential to identify the different stages in the curing process. It is obvious that the piezoelectric sensor network will provide important technical support for composite materials with the structure and function integrated.


Author(s):  
Casey Keulen ◽  
Bruno Rocha ◽  
Afzal Suleman ◽  
Mehmet Yildiz

This paper proposes the use of an embedded network of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. A single sensor network is used at each stage of life of a RTM composite panel: flow monitoring, cure monitoring and health monitoring. A laboratory scale RTM apparatus was designed and built with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors into the mold has also been developed. Both Fiber Bragg Gratings (FBG) and Etched Fiber Sensors (EFS) have been embedded in composite panels using the apparatus. Etched Fiber Sensors have the capability of detecting the presence of resin. The sensors have proven to be capable of detecting the presence of resin at various locations as it is injected into the mold and have the capability of being multiplexed with FBGs thus reducing the number of ingress/egress locations required per sensor. Two FBGs and three EFSs were embedded on a single optical fiber. Tensile test specimens that contain embedded FBG sensors have also been produced with this apparatus. These specimen and embedded sensors have been characterized using a strain gage and a material testing machine. FBG sensors have been embedded into composite panels also in a manner that is conducive to detecting Lamb waves generated with a centrally located PZT. To detect Lamb waves a high speed, high precision sensing technique is required for embedded FBGs, since these guided waves travel through the material at very high velocities, presenting relatively small strain amplitudes. A technique based in a filter consisting of a second FBG was developed. Since this filter is not dependant on moving parts, it does not limit the velocity or frequency at which the tests can be performed. Preliminary tests performed using this filter showed that it is possible to detect Lamb waves with amplitudes smaller than 1 microstrain. A damage detection algorithm has been developed and is applied to this system in an attempt to detect and localize damages (cracks and delaminations) in the composite structure.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jinghua Dai ◽  
Xiaoqiang Ren ◽  
Peng Wu ◽  
Xiangdong Wang ◽  
Jiang Li ◽  
...  

Abstract Background This study aims to explore the information chain management model of large instrument and equipment inter-working in the operating room (OR) led by information nurses. Methods Through the chain management process of large instruments and equipment in the OR, which was based on information nurses, the management model of inter-working and integrating information chain was established, the key links were controlled, and the whole life cycle management of instruments and equipment from expected procurement to scrapping treatment was realized. Using the cluster sampling method, 1562 surgical patients were selected. Among these patients, 749 patients were assigned to the control group before the running mode, and 813 patients were assigned to the observation group after the running mode. The related indexes for large instrument and equipment management in the department before and after the running mode were compared. Results In the observation group, the average time of equipment registration was (22.05 ± 2.36), the cost was reduced by 2220 yuan/year, and the satisfaction rate of the nursing staff was 97.62%. These were significantly better, when compared to the control group (P < 0.05). Furthermore, the awareness rate of the whole staff for equipment repair application was 95.12%, and the arrival time of maintenance personnel and the examination and approval time of equipment management were greatly shortened (P < 0.05). Conclusion The integrated management model of large instrument and equipment interworking in the OR based on chain flow realizes the whole life cycle management of instruments and equipment, which is essential to improve management efficiency.


2021 ◽  
Vol 13 (15) ◽  
pp. 8427
Author(s):  
Bahareh Nikmehr ◽  
M. Reza Hosseini ◽  
Jun Wang ◽  
Nicholas Chileshe ◽  
Raufdeen Rameezdeen

This article provides a picture of the latest developments in providing BIM-based tools for construction and demolition waste (CDW) management. The coverage and breadth of the literature on offering BIM-based tools and technologies for dealing with CDW throughout the whole life cycle of construction are investigated, and gaps are identified. Findings reveal that, although various BIM-based technologies are closely associated with CDW, much of the existing research on this area has focused on the design and construction phase; indeed, the problem of CDW in post-construction stages has received scant attention. Besides, the now available tools and technologies are lacking in cross-phase insights into project waste aspects and are weak in theoretical rigor. This article contributes to the field by identifying the intellectual deficiencies in offering BIM-based tools and technologies when dealing with CDW. So, too, it points to major priorities for future research on the topic. For practitioners, the study provides a point of reference and raises awareness in the field about the most advanced available BIM-based technologies for dealing with CDW problems.


2015 ◽  
Vol 808 ◽  
pp. 359-363
Author(s):  
Cristina Feniser ◽  
Florin Lungu

So far little attention has been given the differences or the compatibilities between CSR and innovation. Few works treats CSR in combination with innovation. What exactly is the relationship between CSR and innovation? Recent phenomena such as open innovation is based on the concept that the stakeholder's dialogue that overlaps with some dimensions of CSR. Being innovative means to bring organizational and technical improvements which will translate into a better position in the market. These improvements don't just aim the product, but the process by which it is obtained and its whole life-cycle. We're talking about a new approach to innovation, namely its orientation towards sustainability. Although SMEs have many features which facilitate implementation of CSR, activities of this type in such organizations are still limited. SMEs managers often make choices that are related to rational management. This leads to divergence between economical and social goals. Through a qualitative exploration of the concepts of CSR and innovation, we wanted to find out from some managers whether there is a link between innovation and CSR in SMEs and whether the activities corresponding to the two concepts overlap in a certain measure.


2014 ◽  
Vol 535 ◽  
pp. 346-349
Author(s):  
Mei Wang ◽  
Ming Yang ◽  
Jun Liu ◽  
Jian Fen Li

Effect and benefits of a product or service could be analyzed and evaluated by life cycle assessment during the whole life cycle. Urban sewage treatment plants could improve and control urban water pollution escalating, but it also had certain harm to environment. Effect and benefits of urban wastewater treatment plant A and B were analyzed and evaluated, 13 factors were selected, and comprehensive benefits were researched quantificationally using the method of analytic hierarchy process. It found that urban wastewater treatment plant A who applied A/O process had better benefits than urban wastewater treatment plant B who applied BIOLAK process.


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