Study on the integrity detection and evaluation method of damaged pipeline
To detect the integrity of damaged pipeline and accurately evaluate its damaged condition, a CCD image data guided digital automatic ultrasonic testing system was designed to realize the dynamic measurement of a pipeline damaged surface, and extract the characteristic parameter of damaged pipeline. Based on the three-dimensional discrete point set which gathered to describe the integrity of damaged pipeline, we establish a damaged pipeline entity model which is closer to the actual condition, analyze and simulate mechanical properties under the actual load by using the numerical simulation software (ABAQUS), to get the most dangerous region and the trend of stress and displacement. This method provides more reliable reference for integral safety analysis and evaluation of damaged pipeline.
THE APLLICATION OF ABAQUS SOFTWARE IN THE PIPE/SOIL INTERACTION
The pipe-soil contact pair has been established by the master-slave method of the ABAQUS software,and also the finite element model has been established.The constitutive models of soil,such as nonlinear elastic,porous elastic and Ramberg-Osgood models have been adopted relatively.The relationship between the pipe's subweights and pipe's penetration has been obtained,and also soil lateral mounding has been obtained in the computation.The results have shown that computation is in accordance with some test results,which indicates the pipe/soil interaction analysis is feasible by ABAQUS software.
The Accuracy of Reported Insurance Status in the MEPS
Estimates of the number of insured and uninsured Americans are watched by numerous policymakers and the public, yet studies find respondents do not report their insurance status perfectly. Using four sources of validation data, including surveys of employers and providers, this paper assesses the quality of respondents' reports of private insurance and uninsurance in the Medical Expenditure Panel Survey Household Component (MEPS-HC), a nationally representative household survey. Regression analysis is used to assess the extent to which factors are associated with disagreements in reported insurance status across sources.