Investigation of the heat distribution in dry friction systems during fade and recovery using fiber-optic sensing and infrared technology

The design of dry-running friction pairings and systems determines not only their installation space and costs,but also their reliability under critical load conditions,for example in emergencies,in the case of faults,and in the event of misuse.While knowledge of the contact pattern is highly important for the development of clutches and brakes,the contact-related measurement of the temperature of these systems has not yet been solved in a satisfactory manner.Despite its importance,the temperature distribution has only been measured in a few studies.Typically,temperature measurements of complete clutches and brakes are carried out using thermocouples only.In this study,a new innovative test setup is presented.This setup is able to measure the heat distribution of the lining and the steel disk of a brake with high spatial resolution by means of fiber optic sensing technology and thermography.As a novelty,it enables measurement of the heat distribution and allows to correlate it with the fade and recovery behavior.Contrary to the expectations,the contact pattern is heterogeneous in circumferential direction.Possible causes are discussed using simulation results.Along with surface analysis,the new setup contributes to the investigation of the causes of fade and recovery.

Temperature Field of PC Box Girder Bridge Based on GPRS Temperature Collection System

In order to study the temperature distribution and the corresponding temperature effects on pre-stressed concrete（PC） curved box girder bridge in Shandong Province, this paper builds and adopts an automatic remote real-time temperature collection system to collect temperature data on site, and further uses the software ANSYS for analysis. Based on the comparisons between the measured data and the simulation results, the following conclusions can be drawn： 1 Our temperature monitoring system is reliable; 2 The corresponding measured data of the web plate and flange plate exposed to the sun, vary more severely than that at other positions, so these plates need higher standard design and construction requirements; 3 In the cold wave where still is sunshine, the box girder temperature effect behaves as sine-like curve.

Inner wall running state monitoring for the main pipe of nuclear power

The heat conduction equation is solved in this paper under specific boundary conditions.The coefficients of the obtained distribution equation are simplified with the piecewise integral method.Then the associated model for the cylindrical thermal equipment is established.The relationship of the surface temperatures,the material properties and the inner wall state of the cylindrical thermal equipment is described in the associated model.This model is applied to the inner wall running state monitoring of the main pipe.A multi-channel distributed optical fiber temperature measurement system is designed to acquire the external surface temperatures of the main pipe.Then the associated model can be used to analyze the surface temperature data of the main pipe.The location and the physical dimension of the inner wall defect can be got.Therefore,the inner wall defect monitoring of the main pipe can be realized.The feasibility of this method is verified by experiment.This method also provides a theoretical basis for the real-time monitoring of the main pipe’s internal state.