Development of Structural Monitoring and Inspection on Baysian Reliability Analysis

在本研究中，结构监测和检测的贝叶斯可靠性分析的适用性进行了讨论。主要研究结果如下：（1）结构疲劳寿命具有高度的不确定性和风险性。为了设计这样的系统，有必要考虑几个随机因素。随着结构的老化，初始成本、检查、维护和可靠性水平之间的关系变得重要，必须对其进行研究，以便从成本效益的角度实现良好的设计。本文分析了这种关系，并提出了一种方法，以采取最佳的决定之间的一组替代品结构尺寸使用一类新的贝叶斯损失函数的基础上的概念下，设计和过度。(2)对金属结构疲劳监测的两种方法--疲劳裂纹检测和疲劳寿命预测进行了试验研究。在实验的基础上制作了导电薄膜传感器、导电涂料传感器、塑料光纤传感器、玻璃光纤传感器和碳纤维传感器。将传感器通过胶粘剂或涂料粘贴在焊接接头模型和致密试件的表面，通过疲劳试验检测传感器的性能，并研制了胶粘剂型疲劳试样指示器。试件主体为一长60 mm、宽10 mm、厚0.25mm的中心裂纹薄板，由低碳钢制成。板的长度的中间部分由聚四氟乙烯膜涂覆，并且整体夹在两个薄环氧树脂板之间。将试样通过胶粘剂粘接在光滑试件上，通过脉动拉伸和全反向疲劳试验研究了试样的性能。(3)本文试图探讨光纤应变测量的可能性。

In the present investigation, the applicability of structural monitoring and inspection on Baysian reliability analysis are discussed. The main results are summarized as follows ;(1) Life of structures which are subject to fatigue failures involves high degree of uncertainty and risk. In order to design such systems it is necessary to take into account several stochastic elements. As the structure ages, the relationship among initial cost, inspections, maintenance and reliability level becomes important, and it has to be studied in order to achieve a good design from the costeffectiveness point of view. This paper analyzes this relationship and proposes a method to take the best decision among a set of alternatives structural regarding structural dimensions using a new class of Baysian loss functions that are based on the concepts of under and over design.(2) Two type of fatigue monitoring methods are experimentally examined for metal structures ; fatigue crack detection and fatigue life prediction.As the detection method, five kinds of crack sensors, i.e., conductive film-sensor, conductive-paint sensor, plastic optical-fiber sensor, glass optical-fiber sensor and carbon-fiber sensor are made on an experimental basis. The sensors are bonded on the surface of a welded joint model and a compact specimen by adhesives or painting, and performances of each sensor are examined through the fatigue tests.As the prediction method, a fatigue coupon indicator of adhesive-type is developed. The main body of the coupon is a center cracked thin plate with 60mm-long, 10mm-width and 0.25mm-thickness, madefrom mild steel. The middle part in length of the plate is coated by Teflon film and the whole is sandwiched in between two thin epoxy resin plates. The coupon is bonded on a smooth specimen by adhesives, and the performance is investigated by pulsating tension and fully reversed fatigue tests.(3) We try to investigate on possibility of strain measurement by optical fiber.