Rebecca Ferreira | Unesp - Academia.edu (original) (raw)
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University of Belgrade, Faculty of Mechanical Engineering
University of Belgrade, Faculty of Mechanical Engineering
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Papers by Rebecca Ferreira
Pressure vessels are designed to contain pressure and withstand the operating mechanical and ther... more Pressure vessels are designed to contain pressure and withstand the operating mechanical and thermal transients for a specified design life. In addition they are designed to safety to leak before break (LBB). LBB describes the situation in which a leak occurs before a complete double-ended break of a component. Ductile and tough materials are widely used in nuclear pressure vessels, because of their high resistance to catastrophic rupture. The design process involves fatigue analysis to demonstrate that there is insignificant crack growth a postulated surface crack during the entire design life. However in terms of LBB the significant parameter is the elastic-plastic fracture toughness, and the material strength. However based on assessment based on linear elastic fracture mechanics, the candidate materials are carbon steels, low alloy steels and stainless steels, which interestingly are the materials that are used for pressure vessels. In terms of the fatigue crack initiation, the appropriate parameters are the threshold stress intensity factor range and the endurance limit and the material selection is based on these parameters.
Lower bound limit load theory Design by analysis (DBA) Pressure vessel a b s t r a c t Stress cat... more Lower bound limit load theory Design by analysis (DBA) Pressure vessel a b s t r a c t Stress categorization in the design by analysis (DBA) procedure for protection against plastic collapse in pressure vessel has been problematic during application. For example, it is difficult to determine the proportion of primary and secondary stress at the gross structural discontinuities. This paper proposes a new method to avoid the stress categorization by extending the current elastic stress analysis method in ASME Code based on lower bound limit load theory. The proposed method assumes a stress distribution along the stress classification line (SCL) in the form of limit stress state for a beam under membrane and bending load, rather than a linear stress distribution. The effectiveness of proposed method is verified by comparing with the elastic stress analysis, Limit-Load Analysis, Elastic-Plastic stress Analysis of the ASME Code for axisymmetric pressure vessels. The results concluded that the new method is effective easy to use.
The effect of several Design Codes on the total cost of pressure vessels is studied. It is shown ... more The effect of several Design Codes on the total cost of pressure vessels is studied. It is shown that a significant reduction in cost can only be achieved through careful consideration of the management of production, including the inspection procedure. Comparative values are given to the costs involved in the various elementary operations that constitute the complete design, fabrication, erection and commissioning for conventional vessels.
Pressure vessels are designed to contain pressure and withstand the operating mechanical and ther... more Pressure vessels are designed to contain pressure and withstand the operating mechanical and thermal transients for a specified design life. In addition they are designed to safety to leak before break (LBB). LBB describes the situation in which a leak occurs before a complete double-ended break of a component. Ductile and tough materials are widely used in nuclear pressure vessels, because of their high resistance to catastrophic rupture. The design process involves fatigue analysis to demonstrate that there is insignificant crack growth a postulated surface crack during the entire design life. However in terms of LBB the significant parameter is the elastic-plastic fracture toughness, and the material strength. However based on assessment based on linear elastic fracture mechanics, the candidate materials are carbon steels, low alloy steels and stainless steels, which interestingly are the materials that are used for pressure vessels. In terms of the fatigue crack initiation, the appropriate parameters are the threshold stress intensity factor range and the endurance limit and the material selection is based on these parameters.
Lower bound limit load theory Design by analysis (DBA) Pressure vessel a b s t r a c t Stress cat... more Lower bound limit load theory Design by analysis (DBA) Pressure vessel a b s t r a c t Stress categorization in the design by analysis (DBA) procedure for protection against plastic collapse in pressure vessel has been problematic during application. For example, it is difficult to determine the proportion of primary and secondary stress at the gross structural discontinuities. This paper proposes a new method to avoid the stress categorization by extending the current elastic stress analysis method in ASME Code based on lower bound limit load theory. The proposed method assumes a stress distribution along the stress classification line (SCL) in the form of limit stress state for a beam under membrane and bending load, rather than a linear stress distribution. The effectiveness of proposed method is verified by comparing with the elastic stress analysis, Limit-Load Analysis, Elastic-Plastic stress Analysis of the ASME Code for axisymmetric pressure vessels. The results concluded that the new method is effective easy to use.
The effect of several Design Codes on the total cost of pressure vessels is studied. It is shown ... more The effect of several Design Codes on the total cost of pressure vessels is studied. It is shown that a significant reduction in cost can only be achieved through careful consideration of the management of production, including the inspection procedure. Comparative values are given to the costs involved in the various elementary operations that constitute the complete design, fabrication, erection and commissioning for conventional vessels.