Research and Development of Measurement Method for Structural Fracturing Process in Shake Table Tests Using Image Processing Technique

2004 ◽  
Vol 126 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Tadashi Mikoshiba

The largest three-dimensional shake table is now being constructed in Hyogo prefecture, Japan for a solution of fracturing process of structures, buildings, and soils. However, it seems to be difficult to measure the fracturing processes of the structures during severe earthquake by using conventional methods and equipment, because the three-dimensional measurement of larger dynamic displacement in excess of elastic region of the structure will be the key to a solution and cannot be obtained by any of the vibration pick-ups such as displacement transducers and so on. In this study, R&D of the new measurement method to clarify the fracturing process of the structures by applying a so-called motion capture technique, which has been mainly studied for modeling of human actions and motions. This paper describes the concept of the system, the outline of the proto-type image processing system developed in the study and the results of the shake table test using five-story steel-structure model to investigate the measurable accuracy of the system.

Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Hidetaka Hayashi

In recent years, the importance of the fracturing test using the full-scale model is recognized in order to upgrade an earthquake resistant design. It is, moreover, important to develop a new measurement method which can measure a complex three-dimensional behavior in such fracturing test. This study has been doing research and development of three-dimensional measurement method using an image processing technique for a measurement of dynamic displacement in shake table test without any contact. This measurement system is a very convenient system because it can measure the three-dimensional dynamic displacement in the simple experimental condition that the several makers are only attached to the surface of an experimental structure. The system therefore is the most suitable measurement system for an evaluation of complex three-dimensional behavior of test model. The fundamental hardware and software for the measurement system has been constructed until now. The fundamental dynamic measurement accuracy and effectiveness of the measurement system has been also confirmed from several shake table tests. This paper describes the measurement results of shake table test using historical wooden structure and actual wooden house model in the largest shake table facilities at E-Defense, and evaluates synthetic measurement performance of the developed measurement system.


Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Hiroki Mizuno

In recent years, the importance of the fracturing test using the full-scale model is recognized in order to upgrade an earthquake resistant design. It is, moreover, important to develop a new measurement method which can measure a complex three-dimensional behaviour in such fracturing test. This study has been doing research and development of three-dimensional measurement method using an image processing technique for a measurement of dynamic displacement in shake table test without any contact. This measurement system is a very convenient system because it can measure the three-dimensional dynamic displacement in the simple experimental condition that the several makers are only attached to the surface of an experimental structure. The system therefore is the most suitable measurement system for an evaluation of complex 3-dimensional behavior of test model. Fundamental hardware and software for the measurement system has been constructed until now. The fundamental dynamic measurement accuracy and effectiveness of the measurement system has been also confirmed from several shake table tests. This paper describes the examination of the upgrading for the measurement accuracy in actual fracturing test. Moreover, the shake table test results using actual wooden house model were also indicated.


Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Tadashi Mikoshiba

This study has been examined about a three-dimensional measurement method that can measure a position and an attitude of test object without any contact. Fundamental hardware and software in measurement system has been constructed until now. Moreover, the fundamental dynamic measurement accuracy and effectiveness of the proposed measurement system has been confirmed from the several shake table tests. This paper describes the effectiveness of the proposed system for the measurement in fracturing test using real scale wooden house model.


Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Yasushi Niitsu

This study has been doing research and development of 3-dimensional measurement method using the image processing technique for the measurement of dynamic displacement in shake table test. This measurement system is a very convenient system because it can measure the three-dimensional dynamic displacement in shake table test in which the several makers are only attached to the surface of an experimental structure. The system therefore is the most suitable measurement system for an evaluation of complex 3-dimensional behavior of experimental model. Fundamental hardware and software for the measurement system have been constructed until now. The fundamental dynamic measurement accuracy and effectiveness of the measurement system have been also confirmed from several shake table tests. This paper describes the dynamic measurement accuracy in shake table test in with the experimental model has several rotational behaviors, and also summarizes the synthetic performance of the proposed measurement system.


2003 ◽  
Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Yasushi Niitsu ◽  
Tadashi Mikoshiba ◽  
Daisuke Nakano

This study has been doing research and development of 3-dimensional measurement method using an image processing technique for a measurement of dynamic displacement in shake table test. This measurement system is a very convenient system because it can measure the 3-D dynamic displacement in shake table test in which the several makers are only attached to the surface of an experimental structure. The system therefore is the most suitable measurement system for an evaluation of complex 3-dimensional behaviour of test model. Fundamental hardware and software for the measurement system has been constructed until now. The fundamental dynamic measurement accuracy and effectiveness of the measurement system has been also confirmed from several shake table tests. In this paper, the dynamic measurement accuracy in three measurement units on the assumption of practical use is described from the results of shake table tests in National Research Institute for Earth Science and Disaster Prevention using the collapse building and the inverted pendulum model.


2019 ◽  
Vol 109 (2) ◽  
pp. 98-107
Author(s):  
Kit-lun Yick ◽  
Wai-ting Lo ◽  
Sun-pui Ng ◽  
Joanne Yip ◽  
Hung-hei Kwan ◽  
...  

Background: Accurate representation of the insole geometry is crucial for the development and performance evaluation of foot orthoses designed to redistribute plantar pressure, especially for diabetic patients. Methods: Considering the limitations in the type of equipment and space available in clinical practices, this study adopted a simple portable three-dimensional (3-D) desktop scanner to evaluate the 3-D geometry of an orthotic insole and the corresponding deformities after the insole has been worn. The shape of the insole structure along horizontal cross sections is defined with 3-D scanning and image processing. Accompanied by an in-shoe pressure measurement system, plantar pressure distribution in four foot regions (hallux, metatarsal heads, midfoot, and heel) is analyzed and evaluated for insole deformity. Results: Insole deformities are quantified across the four foot regions. The hallux region tends to show the greatest changes in shape geometry (17%–50%) compared with the other foot regions after 2 months of insole wear. As a result of insole deformities, plantar peak pressures change considerably (–4.3% to +69.5%) during the course of treatment. Conclusions: Changes in shape geometry of the insoles could be objectively quantified with 3-D scanning techniques and image processing. This investigation finds that, in general, the design of orthotic insoles may not be adequate for diabetic individuals with similar foot problems. The drastic changes in the insole shape geometry and cross-sectional areas during orthotic treatment may reduce insole fit and conformity. An inadequate insole design may also affect plantar pressure reduction. The approach proposed herein, therefore, allows for objective quantification of insole shape geometry, which results in effective and optimal orthotic treatment.


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