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The explosion accident caused by residual pressure is one of the most common kinds of accidents in quick actuating pressure vessels. And it is important to provide some reliable methods, which can give reasonable analysis of the explosion. In this study, experiments of the explosion are preformed by using two quick actuating pressure vessels with residual pressure, and a new mathematical model is presented. The model is based on the combination of the Spalart–Allmaras turbulence fluid model and Newton’s second Law for the solid motion. And the model is solved with local remeshing method. By performing the simulation with the same parameters of experiments, the results of the simulation confirm the accuracy of the model. And the results shows the crucial factor of vessel structure, which the maximum ejected speed of the lid highly depends on. Based on that, the optimal design of the structure is presented, which can provide better security.

Stainless steel bellows expansion joint is an important part of city gas pipelines. In recent years, accidents occur frequently due to stress corrosion. The research on failure mechanism for bellows has high practical significance. According to magnetic variety of the deformation-induced martensite, the martensite phase content was tested by using the MP30E-S measurement instrument, for the bellows made of the SUS304 and SUS316L materials separately formed by machine-bulge method and SUS304 materials formed by hydraulic pressure method which there is or not a solution treatment respectively. The results showed that, there are great relations between the martensite phase content and materials, deformation rate, and heat treatment. The martensite phase content of SUS316L is less than SUS304, the more martensite phase content because the more deformation rate, there are less and even martensite phase after solution treatment.

Quick actuating pressure vessels are widely used in chemical industry, food processing, pharmacy, etc. The explosion accident caused by residual pressure is one of the most common kinds of accidents in quick actuating pressure vessels. So, it is important to provide some reliable inspection methods, which can protect them from explosion. In this study, experiments and simulation on the explosion of quick actuating pressure vessels are preformed. The relative safe residual pressure in quick actuating pressure vessels was put forward. And a rational residual pressure for quick actuating pressure vessels should be fixed considering the safety and efficiency.Copyright © 2012 by ASME

An integral FEA model and a nonlinear contact algorithm were emplyed for the double-cone seal structure, which were applied on the large-sized double-cone seal structure under internal pressure. The stress distribution of double-cone ring and gasket under pre-tightening and working conditions, as well as the influence of pre-tightening force and internal pressure on the gasket stress, double-cone ring strain and radial clearance, were obtained. If the radial clearance was designed according to g⩾0.1% D1, the material of double-cone ring would yield globally. Meanwhile, If the radial clearance was designed according to g⩽0.05%D1, the sealing performance in the pressurizing process would not be ensured. A radial clearance g=(0.075%∼0.1%)D1 is recommended.

Recently, acoustic testing method has been widely used for valve leakage inspection. Traditional method has difficulty carrying out research on the acoustic testing of valve leakage due to the complex geometry of the valve and the effect of flow on sound field. Thus, a numerical method was put forward based on Reynolds average N-S equation and k – e equation in order to investigate the flow of the inner leakage of ball valve, needle valve and gate valve. Furthermore, difference time domain method was adopted to simulate the noise field of the flow based on Lighthill acoustic equation. And the characteristics of acoustic distribution were obtained. The results showed that turbulent flow was the main cause of jet noise inner the valve due to gas leakage. And the acoustic distribution had directivity. There were about 10 ∼ 25dB difference between the upstream and downstream of the leaking valve. The position with the highest sound pressure was also found out.Copyright © 2009 by ASME

The strength and hardness tests to the experiment dryer were carried on, from the relation of strength and hardness, the relative hardness RH is 0.8 according to ‘principle met using’. The velocity of sound should be measured first in the thickness measurement, the ‘false’ thickness phenomenon in dryer flange and the convex transition segment were discovered. The ultrasonic examination characteristics of the cast iron dryer was analyzed, the sensitivity of various sensors were carried on. The small angle double crystal longitudinal wave sensor can examine the Φ3 equivalent diameters of the volume defects, and the big angle double crystal longitudinal wave sensor can examine 2 mm deep surface crack of the body and the transition area. The safety assessment on 2 mm deep surface crack was carried on.

Austenitic stainless steel is widely used for boiler and pressure vessels, however the actual stress-based method to determine the allowable stress limits the full usage of plastic metals such as austenitic stainless steel that with low ratio of yield to tensile strength. The parts of ASME and European codes of pressure vessels have been attention of it and some measures have been taken to increase the allowable stress by decreasing the design factors or change the specified yield strength from 0.2% proof strength to 1.0% proof strength etc.; the other important method is to increase the yield strength by pressure strengthening. A series theoretic computation and experimental analysis were carried out based on the systematical survey of these codes including Chinese GB150, ASME VIII-1, ASME VIII-2, EN13345 and EN13458 etc, and the result showed the difference of allowable stress among these codes and indicated that Chinese GB150 is most conservative with high strength margin, whereas EN13458 attendance with pressure strengthening is the best solution to increase the allowable stress as well, which increased the allowable stress 99.3% than that of GB150.Copyright © 2008 by ASME

Austenitic stainless steel exhibits excellent ductility and high strain hardening. When the steel is loaded in tension to a stress σk above its proof strength and then unloaded a permanent plastic elongation will result. If the steel is loaded again it will remain elastic up to this higher stress. This characteristic of the strain hardening offers the space to increase the allowable stress of the steel by pressure strengthening. In practice the finished vessel was loaded by internal pressure to the strengthening stress of σk , which is well above the proof strength of the material and greatly improves the bearing capacity of the vessel. The strain energy function-based principle accompanied with a constraint condition was presented according to the true stress-strain curve of material to determine the strengthening stress of σk . Using this principle, the finite element analysis of pressure strengthening was performed where material and geometrical nonlinearity were considered in the large deformation computation of pressure vessel. Also, the strain under the load steps of the vessel was studied in strengthening operation process, which was coincident with numerical results. For the strengthened pressure vessels, the strength margin was evaluated by the comparison of the measured plastic collapse pressure with the design pressure.Copyright © 2008 by ASME

In this paper, an analysis of the strength of U-shaped bellows is presented. First, an elastic solution of the action of internal pressure and axial displacement is obtained by adopting the thin toroidal shell theory, which coincides extremely well with Anderson's (Analysis of stress in bellows. Part II. Mathematical. NAA-SR-4527, 27 May 1965) and Hamada and Tanazono's (Bull. JSME, 9(35) (1966) 22–513) theoretical solutions; furthermore, these results have been tested by strain gage measurement. Secondly, a curved beam model is used for the elastoplastic analysis of bellows. With the consideration of strain concentration, the fatigue life predicting formula for the bellows expansion joint is derived and validated by the results of fatigue tests. Finally, the structural optimization of U-shaped bellows is carried out with the object of minimizing the maximum elastoplastic strain under the action of displacement.