scholarly journals Underwater Dynamic Response at Limited Points Expanded to Full-Field Strain Response

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Yuanchang Chen ◽  
Dagny Joffre ◽  
Peter Avitabile
Keyword(s):  
Real Time ◽  
Measured Data ◽  
Great Success ◽  
Strain Response ◽  
Full Field ◽  
Field Displacement ◽  
Health Assessments ◽  
Field Response ◽  
Applied Forces ◽  
Measured Response

Expansion of real-time operating data from limited measurements to obtain full-field displacement data has been performed for structures in air. This approach has shown great success, and its main advantage is that the applied forces do not need to be identified. However, there are applications where structures may be immersed in water and the full-field real-time response may be needed for design and structural health assessments. This paper presents the results of a structure submersed in water to identify full-field response using only a handful of measured data. The same approach is used to extract the full-field displacements, and the results are compared to the actual full-field measured response. The advantage of this approach is that the force does not need to be identified and, most importantly, the damping and fluid–structure interaction does not need to be identified in order to perform the expansion. The results show excellent agreement with the measured data.

An Approach to Approximate the Full Strain Field of Turbofan Blades During Operation

2018 ◽  
Author(s):  
Gen Fu ◽  
Alexandrina Untaroiu ◽  
Walter O’Brien
Keyword(s):  
Numerical Model ◽  
Cantilever Beam ◽  
Strain Field ◽  
Measured Data ◽  
Mode Shapes ◽  
Beam Model ◽  
Reference Solution ◽  
Full Field ◽  
Field Response ◽  
Critical Locations

The measurement of the aeromechanical response of the fan blades is important to quantifying their integrity. The accurate knowledge of the response at critical locations of the structure is crucial when assessing the structural condition. A reliable and low cost measuring technique is necessary. Currently, sensors can only provide the measured data at several discrete points. A significant number of sensors may be required to fully characterize the aeromechanical response of the blades. However, the amount of instrumentation that can be placed on the structure is limited due to data acquisition system limitations, instrumentation accessibility, and the effect of the instrumentation on the measured response. From a practical stand point, it is not possible to place sensors at all the critical locations for different excitations. Therefore, development of an approach that derives the full strain field response based on a limited set of measured data is required. In this study, the traditional model reduction method is used to expand the full strain field response of the structure by using a set of discrete measured data. Two computational models are developed and used to verify the expansion approach. The solution of the numerical model is chosen as the reference solution. In addition, the numerical model also provides the mode shapes of the structure. In the expansion approach, this information is used to develop the algorithm. First, a cantilever beam model is created. The influences of the sensor location, number of sensors and the number of modes included are analyzed using this cantilever beam model. The expanded full field response data is compared with the reference solution to evaluate the expansion procedure. The rotor 67 blade model is then used to test the expansion method. The results show that the expanded full field data is in good agreement with the calculated data. The expansion algorithm can be used for the full field strain by using the limited sets of strain data.

Safety Monitoring and Warning System for Subway Construction Workers using Wearable Technology

2019 ◽  
Vol 13 ◽  
Author(s):  
Jun-hua Chen ◽  
Da-hu Wang ◽  
Cun-yuan Sun
Keyword(s):  
Real Time ◽  
Video Surveillance ◽  
Early Warning ◽  
Warning System ◽  
Safety Monitoring ◽  
Wearable Technology ◽  
Construction Workers ◽  
Great Success ◽  
Subway Construction ◽  
Monitoring And Early Warning

Objective: This study focused on the application of wearable technology in the safety monitoring and early warning for subway construction workers. Methods: With the help of real-time video surveillance and RFID positioning which was applied in the construction has realized the real-time monitoring and early warning of on-site construction to a certain extent, but there are still some problems. Real-time video surveillance technology relies on monitoring equipment, while the location of the equipment is fixed, so it is difficult to meet the full coverage of the construction site. However, wearable technologies can solve this problem, they have outstanding performance in collecting workers’ information, especially physiological state data and positioning data. Meanwhile, wearable technology has no impact on work and is not subject to the inference of dynamic environment. Results and conclusion: The first time the system applied to subway construction was a great success. During the construction of the station, the number of occurrences of safety warnings was 43 times, but the number of occurrences of safety accidents was 0, which showed that the safety monitoring and early warning system played a significant role and worked out perfectly.

Extracting full-field dynamic strain response of a rotating wind turbine using photogrammetry

2015 ◽  
Author(s):  
Javad Baqersad ◽  
Peyman Poozesh ◽  
Christopher Niezrecki ◽  
Peter Avitabile
Keyword(s):  
Wind Turbine ◽  
Dynamic Strain ◽  
Strain Response ◽  
Full Field ◽  
Field Dynamic

Real-Time Micro-Fluidic Chip Pressure Control System Base on the Optical Interference

2014 ◽  
Vol 494-495 ◽  
pp. 1274-1277
Author(s):  
Kan Liu ◽  
Hao You
Keyword(s):  
Control System ◽  
Real Time ◽  
Measurement System ◽  
Interference Fringe ◽  
Pressure Control ◽  
Measured Data ◽  
Optical Interference ◽  
Interference Fringes ◽  
Pressure Control System

This article introduces a measurement system based on LabVIEW used for optical interference fringe on micro-fluidic chips. This system mainly uses cameras to capture real-time images of wedge interference fringe on micro-fluidic chips, then the collected images will be binarized by LabVIEW. The processed images will be divided by zone , determine the flatness and gap thickness of the micro-fluidic chips by interference fringes with different directions of deflection and numbers. Finally, feedback from measured data will be used to adjust the flatness and gap thickness of micro-fluidic chips in order to meet the requirement of tests.

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