This paper provides a comparison between test and analysis results for bursting of thin toroidal shells. Testing was done by pressurizing two toroidal shells until failure by bursting. An analytical criterion for bursting is developed based on good agreement between structural instability predicted by large strain-large displacement elastic-plastic finite element analysis and observed burst pressure obtained from test. The failures were characterized by loss of local stability of the membrane section of the shells consistent with the predictions from the finite element analysis. Good agreement between measured and predicted burst pressure suggests that incipient structural instability as calculated by an elastic-plastic finite element analysis is a reasonable way to calculate the bursting pressure of thin membrane structures.
Tachograph recorders were installed in 224 vehicles of a metropolitan police department to monitor vehicle operation in an attempt to reduce the rate of accidents. Police sergeants reviewed each tachograph chart and provided feedback to officers regarding their driving performance. Reliability checks and additional feedback procedures were implemented so that upper level supervisors monitored and controlled the performance of field sergeants. The tachograph intervention and components of the feedback system nearly eliminated personal injury accidents and sharply reduced accidents caused by officer negligence. A cost-benefit analysis revealed that the savings in vehicle repair and injury claims outweighed the equipment and operating costs.
Program evaluation can provide objective information relevant to decisions on program maintenance. A program to address problems in the preparation of criminal investigation reports in a metropolitan police department was evaluated. The program permanently altered environmental conditions under which reports were prepared to facilitate performance. Police officers, who had previously prepared reports without assistance, visited the Case Preparation Room to prepare reports with assistance from office personnel. Compared to reports prepared without assistance, reports prepared in the Case Preparation Room documented more case elements required by the state legal code for criminal prosecution, were completed in fewer days following arrests, and received higher ratings from Assistant District Attorneys. Operation of a permanent program available to approximately 945 officers proved a practical solution to improving the preparation of criminal investigation reports.
A test program was conducted to investigate the inelastic response behavior of internally pressurized tubes subjected to dynamic bending and torsion loads. The basic experiment was a drop test in which the cantilever tube was dynamically loaded by a torque arm with a concentrated weight at the end. The experimental data consist of strain versus time records and peak and permanent deflections. Analytical predictions of the response were made using a lumped parameter beam model of the structure. This simple representation of the pressurized tube is made possible by use of an approximate analytical model for the inelastic deformation of a pipe element subjected to pressure, bending and torsion. The predicted responses are compared with measured responses to assess the accuracy of the models.
An approximate model for the elastic-plastic analysis of a pipe element under combined loading is developed. The model is obtained by generalizing a limit load solution for combined pressure, bending, torsion and axial load to include strain hardening. For various combinations of loading of tubes, curvatures and twist angles are predicted and compared with experimental results and those predicted by a more rigorous analytical approach. The comparison shows that good results are obtained from the approximate model.