The ASME pressure vessel's hole reinforcement design addresses localized stress concentration, stemming primarily from a precise understanding of the impact of holes. The ASME pressure vessel itself is originally uniformly stressed. A hole disrupts structural continuity, leading to a significant increase in stress at the edge of the hole and the formation of a stress concentration area. The core principle of the reinforcement design is to distribute this concentrated stress over a wider area by rationally increasing local structural strength, thus preventing fatigue damage or cracking caused by excessive local stress over long-term use.
The performance matching of the reinforcement material with the ASME pressure vessel itself is fundamental to stress distribution. The design ensures that the reinforcement component's material has similar mechanical properties, including strength, toughness, and deformation capacity, to the ASME pressure vessel's main material. This ensures that, under pressure, the reinforcement and the vessel can synergize and withstand stress, avoiding stress concentration at the connection point due to material property differences. This ensures uniform stress distribution over a larger area and reduces the risk of localized overload.
The design of the reinforcement structure directly influences the effectiveness of stress distribution. Common reinforcement methods include overall wall thickening around the opening or installing specialized reinforcement rings around the opening. These structures increase local thickness and rigidity, expanding the load-bearing area and distributing stress previously concentrated at the opening's edges toward the reinforced area. Furthermore, the reinforcement's dimensions are optimized based on the opening size and the operating pressure of the ASME pressure vessel to ensure effective stress distribution without causing new, uneven stress distribution due to excessive reinforcement.
The transition design within the reinforced area avoids secondary stress concentration at corners. At the connection between the reinforcement component and the ASME pressure vessel, a gently rounded or sloped transition is used, rather than a right angle or abrupt transition. This smooth transition allows stress to be naturally distributed during transfer, eliminating new stress peaks at the connection edge. This ensures a more uniform stress distribution across the entire reinforced area, further reducing the potential for localized damage.
The reinforcement design reduces stress concentration by optimizing the force transfer path. Openings change the direction of pressure transmission within the ASME pressure vessel. Reinforcement structures, through appropriate shape design, direct the pressure load away from the opening edge and toward the wider ASME pressure vessel wall. For example, reinforcement components extend beyond the opening edge, distributing the forces previously borne solely by the opening edge to a wider area of the ASME pressure vessel through the reinforcement structure, thereby reducing stress levels near the opening.
The ASME code's strict definition of reinforcement coverage ensures effective stress distribution. The design clearly defines the required reinforcement coverage area, ensuring that the reinforcement structure fully covers the critical stress concentration areas. The extension length of the reinforcement components, both radially and axially, is determined based on the opening size and the load conditions of the ASME pressure vessel. This ensures adequate support in the areas of greatest stress concentration, avoiding incomplete stress distribution due to insufficient reinforcement coverage.
Precision control during the manufacturing process ensures the effectiveness of the reinforcement design. During the welding and joining process of the reinforcement components, strict quality control is applied to ensure that the reinforcement is tightly integrated with the ASME pressure vessel body, without gaps or loose connections. Good joint quality allows for smooth stress transfer between the two, preventing the formation of new stress concentration points due to poor connections. Furthermore, post-manufacturing inspection verifies the dimensions and joint quality of the reinforcement structure to ensure that the actual structure conforms to the design requirements and truly achieves the goal of stress distribution.
