It has been observed that the degree of contact between layers and the reside stresses caased by pre-tension winding of ribbons does not influence bursting pressure of flat steel ribbon-wound pressure vessels. This suggests the idea that the desirzble design criteria for vessels of this type should beaed on bursting failure made. Le. wall thickness, should be determined by bursting pressure which it strongly influneces by friction between layers and laminar effects, It is shown that the probabiliry of bursting failure of vessel for which the bursting pressure is not Iess than 2.5 dedgm pressure, is less than 10-10. An example demonstrates that a design procedure basent on this information not only has significant economic advantages, but also can indi. care bursting probability.

Flat steel ribbon wound pressure vessels have been adopted by the ASME boiler and Pressure Vessel Code, Section Ⅷ, Division J and Divesion 2. An excellent safety and scrive record has been built up in the past 34 years. Based on the interfacial friction model proposed by Zheng [1], a more accurate method for predicting the stresses in a flat steel ribbon wound ressure vessel is offered in this paper, taking account of the axial displacement, the change in the helical winding angle, the interfacial friction between ribbon layers and the effect of lamination. Comparison between experimental results of five test vessels with and inside diameter varying from 350 to 1000mm, four different helical winding angles (18, 24, 27 and 30°), two width-thickness rations of the ribbon (20 and 22.86) and rosults of oalculation using the stress formulae available demonstrates that the method in this paper is more accurate and that interfacial friction gives a marked strengthening contribution to the axial strength of the vessel.

A flat steel ribbon wound pressure vessel was adopted by ASME Code Case 2229 on 16 August 1996. By considering the additional strength caused by friction between ribbon layers, the authors deduced equations for prediction of longitudinal and hoop bursting pressure of such vessels. The calculation results from the equations, which are easy to calculate and convenient to apply in the engineering, are in excellent agreement with experimental results. It is the theoretical base for equal strength design in axial and circumferential direction. In addition, the criterion of failure form of such a vessel is also given.

ASME Code Case 2229 provides minimum requirements for designing and constructing flat ribbon wound layered pressure vessel. The authorhas worked in this field for more than 10 years and describes the design philosophy of the fiat ribbon wound layered pressure vessel through four parts: strength calculation, fatigue strength, engineering design, and nozzle reinforcements. A new joint construction between ribbon wound shell and hemispherical head thinner than shell and comments on the Code Case are also given.

Considering the fact that the required thickness of a hemispherical head for pressure loading is only half of that necessary for a cylindrical shell, the authors have developed a proprietary junction of shell to hemispherical head where the head is thinner than the shell. In the past 5 years, more than 100 high-pressure vessels with such junctions have been manufactured and safely used in the People's Republic of China. Theoretical investigations as well as engineering applications show that such junctions are rational in structure, convenient in fabrication and low in cost. For example, for a vesscl with an inner diameter of 1000 mm and design pressurc of 31.4MPa, using thc new junction, the head weight is reduced by 54.3 and 27.4 per cent respectively in comparison with a forged fiat head and a hemispherical head with equal thickness of shell. The larger the vessel, the grcater the economic benefits it achieves, In this paper, the authors describe its basic structure, stress characteristics and the engineering design method for the unique junction.