Performance degradation of metal rubber seal under high temperature and pressure

2021 ◽  
pp. 095440622110276
Author(s):  
Yalei Zhao ◽  
Hui Yan ◽  
Wei Yao ◽  
Hongyuan Jiang
Keyword(s):  
Test System ◽  
Performance Degradation ◽  
Channel Height ◽  
Rubber Seal ◽  
Degradation Pattern ◽  
Material Creep ◽  
Metal Rubber ◽  
Temperature And Pressure ◽  
Mechanical Devices ◽  
Degradation Indicator

Seals are crucial components of mechanical devices; seal degradation limits the performance of mechanical systems and even causes accidents. In this work, we used a complex sealing test system to conduct long-term leakage experiments of metal rubber seals as a function of temperature and pressure. The leakage rate was the performance degradation indicator. We developed an experimental performance degradation pattern by linear regression. We combined the leakage pattern of metal rubber seals with leakage theory and found that the increase in the equivalent leakage channel height is the immediate reason for metal rubber seal performance degradation, itself fundamentally attributable to the time-dependent plasticity caused by material creep.

scholarly journals Performance Degradation Assessment of Concrete Beams Based on Acoustic Emission Burst Features and Mahalanobis—Taguchi System

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3402 ◽  
Author(s):  
Md Arafat Habib ◽  
Akhand Rai ◽  
Jong-Myon Kim
Keyword(s):  
Acoustic Emission ◽  
Concrete Beams ◽  
Early Stage ◽  
Concrete Structures ◽  
Feature Selection Method ◽  
Noise Removal ◽  
Performance Degradation ◽  
Reinforced Concrete Beams ◽  
Chebyshev Inequality ◽  
Degradation Indicator

Acoustic emission (AE) has been used extensively for structural health monitoring based on the stress waves generated due to evolution of cracks in concrete structures. A major concern while using AE features is that each of them responds differently to the fractures in concrete structures. To tackle this problem, Mahalanobis—Taguchi system (MTS) is utilized, which fuses the AE feature space to provide comprehensive and reliable degradation indicator with a feature selection method to determine useful features. Further, majority of the existing investigations gave little attention to naturally occurring cracks, which are actually more difficult to detect. In this study, a novel degradation indicator (DI) based on AE features and MTS is proposed to indicate the performance degradation in reinforced concrete beams. The experimental results confirm that the MTS can successfully distinguish between healthy and faulty conditions. To alleviate the noise from the DI obtained through MTS, a noise-removal strategy based on Chebyshev inequality is suggested. The results show that the proposed DI based on AE features and MTS is capable of detecting early stage cracks as well as development of damage in concrete beams.

A New Design of Triaxial Test Chamber with Temperature and Pressure for Deep Rock

2011 ◽  
Vol 422 ◽  
pp. 734-738
Author(s):  
Yong Yan Wang ◽  
Nan Qin ◽  
Jian Guang Li ◽  
Ying Li
Keyword(s):  
Testing Machine ◽  
Test Chamber ◽  
Test System ◽  
Axial Displacement ◽  
Cylinder Wall ◽  
Element Analysis ◽  
Deep Rock ◽  
Triaxial Testing Machine ◽  
Temperature And Pressure ◽  
Embedded Type

According to the research of existing triaxial testing machine of deep rock, a new test chamber with temperature-hold and pressure-tight is developed.The features of test box are as follows: a new kind of axial displacement test system with outer embedded type is designed for measuring the axial displacement of samples correctly; the circuit of oiling system is used to keep temperature and pressure; it’s convenient to take down the test box from the machine and the other functions of testing machine are not affected. So the availability factor of instrument can be improved. Finally, the thickness of cylinder wall is calculated, and according to the modeling and finite element analysis based on ANSYS, the results show that the cylinder can meet the working requirement.

Designs of Multiple Microchannel Heat Transfer Systems

2011 ◽  
Author(s):  
Jingru Zhang ◽  
Po Ting Lin ◽  
Yogesh Jaluria
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Optimization Problems ◽  
Numerical Models ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Channel Height ◽  
Physical Constraints ◽  
Temperature And Pressure

In this paper, two different configurations of multiple microchannel heat sinks with fluid flow are investigated for electronic cooling: straight and U-shaped channel designs. Numerical models are utilized to study the multiphysics behavior in the microchannels and validated by comparisons with experimental results. Three responses, including thermal resistance, pressure drop, and maximum temperature, are parametrically modeled with respect to various variables such as dimensions of the channels, total number of channels, and flow rate. Multi-objective optimization problems, which minimize the thermal resistance and the pressure drop simultaneously, are formulated and studied. Physical constraints in terms of channel height, maximum temperature, and pressure are further investigated. The Pareto frontiers are studied and the trade-off behavior between the thermal resistance and the pressure drop are discussed.

Performance degradation assessment of rolling element bearings based on hierarchical entropy and general distance

2017 ◽  
Vol 24 (14) ◽  
pp. 3194-3205 ◽  
Author(s):  
Keheng Zhu
Keyword(s):  
Degradation Process ◽  
Performance Degradation ◽  
Rolling Element Bearings ◽  
Vibration Signals ◽  
Feature Vectors ◽  
Multi Scale ◽  
Nonlinear Dynamic Characteristics ◽  
Rolling Element ◽  
Bearing Vibration ◽  
Degradation Indicator

Performance degradation assessment is crucial to realize equipment’s near-zero downtime and maximum productivity. In this paper, a new method for performance degradation assessment of rolling element bearings is proposed based on hierarchical entropy (HE) and general distance. First, considering the nonlinear dynamic characteristics of bearing vibration signals, the HE method is utilized to extract feature vectors, which can obtain more bearing state information hidden in the vibration signals than sample entropy (SampEn) and multi-scale entropy (MSE). Then, the general distance between the feature vectors of the normal data and those of the tested data is designed as a degradation indicator by combining Euclidean distance and cosine angle distance. The experimental results indicate that this indicator can detect the incipient defects well and can effectively reflect the whole degradation process of rolling element bearings. Moreover, the designed indicator has some advantages over kurtosis and root mean square (RMS) values.

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

1970 ◽  
Vol 28 ◽  
pp. 106-107 ◽  
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
New Zealand ◽  
General Hospital ◽  
Massachusetts General Hospital ◽  
Type I ◽  
Type Ii ◽  
Collaborative Effort ◽  
Temperature And Pressure ◽  
The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

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