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As the width of windings of wound pressure vessels increases, the vessels are categorized as filament-wound, ribbon-wound, thin plate-wound, and finally the conventional multilayered vessels. The filament-wound vessel is one of the wound vessels with small winding width. A multilayered vessel can be regarded as one where the winding width is very great. Based on winding width, the other types of wound vessels are structurally situated between the filament-wound vessel and the multilayered vessel. As the winding width increases, the stress state in the windings gradually changes from purely biaxial to triaxial, and the windings are able to carry more axial load. Therefore, the windings and the inner shell of any wound vessel should mechanically behave in a state between that of the filament-wound and non wound multilayered vessels, depending on winding width. By utilizing an analysis technique, analogous to mathematical interpolation, a new approach for calculating stresses for various wound vessels has been developed. The technique uses the stresses in the filament-wound vessel and of the multilayered vessel with the same dimensions, and compensates for the winding width through the use of a weighting factor. Comparisons between theoretical analyses and experiments are given for fiat steel ribbon-wound vessels. The results show that the calculated stresses at the inside surface of inner shell are in very good agreement with published experimental data.

The flat steel ribbon-wound vessel is a relatively new type of wound pressure vessel. This type of vessel consists of a thin-walled inner core and helically wound flat steel ribbons. The outstanding safety in service of this type of vessel is due, in part, to the large circumferential and axial prestresses introduced during the ribbon-winding process. This paper presents a model for determination of prestresses in such a vessel. The model considers the fabrication procedures producing the prestress in the vessel. Experimental results from tests using full-scale vessels are presented. Agreement between the theoretical model and the experimental results is excellent.

A precision multi-degree-of-freedom measuring (MDFM) system has been developed and implemented for the simultaneous measurement of straightness, pitch, yaw, and roll errors of the moving axes of a CMM. The system is based on the principles of laser alignment and autocollimator. Its measurement principles and the influence of laser beam drifts on its measurement quality have been investigated and some improvement schemes have been implemented. Through the measurements of actual as well as artificially created geometric errors of the CMM, it has been found that the system's accuracy of measuring straightness error components is better than 1 [mu]m and its accuracy for angular error measurements is better than 0.5 arcsec.

Pressure vesSels with wound-flat steel ribbons, also called ribbon-wound vessels, have excellent engineering and economic advantages and are widely used in the People's Republic of China. A brief description of the structure and characteristics, and a comparison between the ribbon-wound technique with other methods are given. In this paper, a new mechanical model for the ribbons, in which the axial displacement and change of spiral angle are taken into account, is put forward. Then the universal formulas for the ribbon are obtained and a precise stress analysis of the vessel is presented. The spring effect of the ribbon layers has a great strengthening effect on the axial strength of the vessel and enables the vessel to support axial load. A formula for the spring effect is suggested. A comparison between theory and test is made, and the results are excellent., Pressure vessels with wound-flat steel ribbons have good performance characteristics and are cost-effective. A new steel ribbon mechanical model was developed considering the axial displacement and change of spiral angle. This model was then applied for the elastic stress analysis of vessels under internal pressure. Results show that steel ribbons increases the axial strength of pressure vessels by 27%.