scholarly journals Forensic Engineering Testing And Analysis Of The Fatigue Failure Of A Hose Clamp

2004 ◽  
Vol 21 (1) ◽  
Author(s):  
Harold Josephs
Keyword(s):  
Fatigue Failure ◽  
Failure Modes ◽  
Fatigue Loading ◽  
Apparent Lack ◽  
Forensic Engineering ◽  
Service Conditions ◽  
Hose Clamp ◽  
Worm Drive

Worm-Drive Band Clamps Or Hose Clamps Are Used Commonly Throughout Industry, Such As In Automotive Applications, To Provide A Reliable Seal Against Liquid Leakage Between A Flexible Hose And A Rigid Male Receiver. The Band Clamp Reliability Is Seldom Questioned And The Typical Engineering Concern Is With The Seal Quality Only. However The Current Investigation Shows That Fatigue Failure Modes Can Develop Under Normal And Foreseeable Conditions Of Use That Will Render A Band Clamp Defective. A Fatigue Failure Of A Band Clamp Would At First Seem Remote And Justifiably Neglected By The Design Engineer Due To The Apparent Lack Of High Cyclic Loads. However Analysis Of A Failed Band Clamp Utilized To Secure A Hose Between An Automotive Radiator And Water Pump Together With Testing For Maximum Strain In An Exemplar Band Clamp-Hose System Has Demonstrated That Fatigue Should Be Considered As Part Of The Initial Design Criteria. The High Clamping Load Capability Of The Band Clamp Together With Low Cyclic Variation In The Load Due To Road And Engine Vibrations Can Indeed Lead To A Fatigue Failure Of The Metal Band. The Fatigue Induced Band Clamp Failure In The Case Study Presented Plus The Testing And Analysis Performed On The Exemplar Clamp, Suggest That Long Term Reliability Of Band Clamps Subjected To Severe Service Conditions May Be Compromised Due To Fatigue Loading.

Safety Assessment of Long Term Serviced Pressure Vessels: A Case Study of Typical Refining and Chemical Plants in China

2021 ◽  
Author(s):  
Zhiyuan Han ◽  
Guoshan Xie ◽  
Haiyi Jiang ◽  
Xiaowei Li
Keyword(s):  
Pressure Vessel ◽  
Safety Assessment ◽  
Failure Modes ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Chemical Plants ◽  
Safety Specification ◽  
Detailed Assessment

Abstract The safety and risk of the long term serviced pressure vessels, especially which serviced more than 20 years, has become one of the most concerned issues in refining and chemical industry and government safety supervision in China. According to the Chinese pressure vessel safety specification TSG 21-2016 “Supervision Regulation on Safety Technology for Stationary Pressure Vessel”, if necessary, safety assessment should be performed for the pressure vessel which reaches the design service life or exceeds 20 years without a definite design life. However, the safety and risk conditions of most pressure vessels have little changes after long term serviced because their failure modes are time-independent. Thus the key problem is to identify the devices with the time-dependent failure modes and assess them based on the failure modes. This study provided a case study on 16 typical refining and chemical plants including 1870 pressure vessels serviced more than 20 years. The quantitative risk and damage mechanisms were calculated based on API 581, the time-dependent and time-independent failure modes were identified, and the typical pressure vessels were assessed based on API 579. Taking the high pressure hydrogenation plant as an example, this study gave the detailed assessment results and conclusions. The results and suggestions in this study are essential for the safety supervision and extending life of long term serviced pressure vessels in China.

scholarly journals Experiment-Based Fatigue Behaviors and Damage Detection Study of Headed Shear Studs in Steel–Concrete Composite Beams

2021 ◽  
Vol 11 (18) ◽  
pp. 8297
Author(s):  
Jun Xu ◽  
Huahuai Sun ◽  
Weizhen Chen ◽  
Xuan Guo
Keyword(s):  
Fatigue Crack ◽  
Fatigue Damage ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Fatigue Loading ◽  
Composite Beams ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
Push Out

Many in-service bridges with steel–concrete composite beams are currently aging and experiencing performance deterioration. Under long-term cyclic loads from traffic on bridges, headed shear studs in steel–concrete composite beams are vulnerable to fatigue damage. The comprehensive understanding of fatigue behaviors and the feasible detection of fatigue damage of headed shear studs is, thus, crucial for the accurate numerical simulation of the fatigue crack propagation process. The paper, thus, experimentally investigates the fatigue behaviors of headed shear studs through push-out tests of three specimens. The fatigue failure modes and cyclic strain evolution of specimens are analyzed. The fatigue lives of headed shear studs are compared with the S–N curves of the AASHTO, Eurocode 4 and BS5400 codes. The fatigue crack details of shear studs in push-out tests are then detected using the ultrasonic non-destructive testing. The results show that the root fracture is the main fatigue failure mode of shear studs under fatigue loading. The fatigue life estimations based on the three current codes (i.e., AASHTO, Eurocode 4 and BS5400) can be safely guaranteed only with different safety redundancies. The strain at the shear stud with fatigue damage shows a consistent increasing trend followed by decreasing behavior after reaching the peak value with the loading cycles. Moreover, the feasibility of the ultrasonic non-destructive testing with the combination of a strain measurement for fatigue crack details detection of headed shear studs in composite beams is proved.

scholarly journals Forensic Engineering Investigation Of Pyrites Expansive Forces And Impact On Long-Term Building Failure

2008 ◽  
Vol 25 (2) ◽  
Author(s):  
Paul G. Carr
Keyword(s):  
Engineering Geology ◽  
Geotechnical Engineering ◽  
Pyrite Oxidation ◽  
Foundation Design ◽  
Highway Engineering ◽  
Forensic Engineering ◽  
Engineering Investigation

There Is A Dearth Of Information Available In The Literature And Published Engineering Texts Addressing The Impacts Of Pyrite Expansion In Buildings (Mitchell And Soga 2005). The Texts Have Largely Been Silent, And The Intersection Of Engineering Geology, Geotechnical Engineering And Foundation Design Has Been Lacking, With The Exception Of Limited Investigations Related To Highway Engineering. Typically Pyrite Has Been Associated With Shale Materials When Used As Fill. Granite, As Well As Other Rocks And Soil Can Also Contain Sufficient Pyrite To Initiate The Destructive Forces Associated With Pyrite Oxidation. In This Case Study Paper, The Insidious And Destructive Forces Of Pyrite Expansion Are Presented. The Long-Term Implications And Strategies For Remediation Are Considered.

Progressive Fatigue Life Prediction of Composite Materials Based on Residual Material Property Degradation Model

2020 ◽  
Author(s):  
J. Nakai-Chapman ◽  
Y. H. Park ◽  
J. Sakai
Keyword(s):  
Composite Materials ◽  
Material Property ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Fatigue Behavior ◽  
Weight Ratio ◽  
Fatigue Loading ◽  
Matrix Cracking ◽  
Degradation Model ◽  
Residual Material

Abstract Anisotropic composite materials have been extensively utilized in mechanical, automotive, aerospace and other engineering areas due to high strength-to-weight ratio, superb corrosion resistance, and exceptional thermal performance. As the use of composite materials increases, determination of material properties, mechanical analysis and failure of the structure become important for the design of composite structure. In particular, the fatigue failure is important to ensure that structures can survive in harsh environmental conditions. The non-homogeneous character of composites induces diverse failure modes of the constituent including fiber fracture, matrix cracking, fiber-matrix interface failure, and delamination. Non-homogeneity of composite materials makes their fatigue behavior very complex in comparison with traditional engineering materials. In this study, a progressive damage theory is extended to simulate fatigue failure of composite laminates under fatigue loading conditions. A residual material property degradation model was employed to predict fatigue damage due to arbitrary stress ratio without performing excessive quantities of testing. This generalized residual material property degradation rule is implemented into user subroutine USDFLD in ABAQUS through which material degradation states are updated over the progressive fatigue loading. The present computational method is verified by comparing the simulated results with the experimental data available in the literature.

Caregivers' Perceptions of Speech-Language Pathologist Talk About Child Language and Literacy Disorders

2020 ◽  
Vol 29 (4) ◽  
pp. 2049-2067
Author(s):  
Karmen L. Porter ◽  
Janna B. Oetting ◽  
Loretta Pecchioni
Keyword(s):  
Language And Literacy ◽  
Collective Case Study ◽  
Study Approach ◽  
School Aged Children ◽  
Speech Language Pathologist ◽  
Therapy Goals ◽  
Semistructured Interviews ◽  
Types Of Information

Purpose This study examined caregiver perceptions of their child's language and literacy disorder as influenced by communications with their speech-language pathologist. Method The participants were 12 caregivers of 10 school-aged children with language and literacy disorders. Employing qualitative methods, a collective case study approach was utilized in which the caregiver(s) of each child represented one case. The data came from semistructured interviews, codes emerged directly from the caregivers' responses during the interviews, and multiple coding passes using ATLAS.ti software were made until themes were evident. These themes were then further validated by conducting clinical file reviews and follow-up interviews with the caregivers. Results Caregivers' comments focused on the types of information received or not received, as well as the clarity of the information. This included information regarding their child's diagnosis, the long-term consequences of their child's disorder, and the connection between language and reading. Although caregivers were adept at describing their child's difficulties and therapy goals/objectives, their comments indicated that they struggled to understand their child's disorder in a way that was meaningful to them and their child. Conclusions The findings showed the value caregivers place on receiving clear and timely diagnostic information, as well as the complexity associated with caregivers' understanding of language and literacy disorders. The findings are discussed in terms of changes that could be made in clinical practice to better support children with language and literacy disorders and their families.

Interrelationships between municipal spatial policy strategy and airport operation and development. Lodz Airport case study

2018 ◽  
Vol 59 (1) ◽  
pp. 65-79
Author(s):  
Katarzyna Nikorowicz-Zatorska
Keyword(s):  
Land Use ◽  
Urban Planning ◽  
Cultural Development ◽  
The Other ◽  
Local Authorities ◽  
Spatial Management ◽  
The One ◽  
Surrounding Areas

Abstract The present paper focuses on spatial management regulations in order to carry out investment in the field of airport facilities. The construction, upgrades, and maintenance of airports falls within the area of responsibility of local authorities. This task poses a great challenge in terms of organisation and finances. On the one hand, an active airport is a municipal landmark and drives local economic, social and cultural development, and on the other, the scale of investment often exceeds the capabilities of local authorities. The immediate environment of the airport determines its final use and prosperity. The objective of the paper is to review legislation that affects airports and the surrounding communities. The process of urban planning in Lodz and surrounding areas will be presented as a background to the problem of land use management in the vicinity of the airport. This paper seeks to address the following questions: if and how airports have affected urban planning in Lodz, does the land use around the airport prevent the development of Lodz Airport, and how has the situation changed over the time? It can be assumed that as a result of lack of experience, land resources and size of investments on one hand and legislative dissonance and peculiar practices on the other, aviation infrastructure in Lodz is designed to meet temporary needs and is characterised by achieving short-term goals. Cyclical problems are solved in an intermittent manner and involve all the municipal resources, so there’s little left to secure long-term investments.

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