# Numerical Simulation and Analysis of the Manufacturing Process of Pre-Bulged Rupture Discs
###### Abstract  
Rupture discs, also known as bursting discs, are indispensable components in fluid-operated systems providing effective protection against hazardous over-pressure or partial vacuum. They belong to a special class of safety devices and are found in a variety of technical applications including pressure vessels, piping systems, reactors and boilers. In all application scenarios, rupture discs act as sacrificial parts that have to fail precisely at a predetermined differential pressure, opening a relief flow path for the working fluid. The membrane employed within rupture discs is usually made out of specific metal alloys or different material layers depending on the particular application. However, for many manufacturers of rupture discs, the production process is characterized by a lack of systematic procedures, relying instead on trial and error as well as empirical values. By means of thorough finite-element-based modeling and simulation of the bulge-forming process of rupture discs, including an elastic-plastic material law, large deformation, as well as contact mechanics, it is possible to accurately predict the resulting stress-strain behavior. All simulation results are rigorously validated through corresponding experiments conducted during the bulge-forming process. Therefore, this contribution provides a reliable basis for the parameter set-up during the manufacturing process of rupture discs. rupture discs; bulge-forming; finite element method; elastic-plastic deformation; contact mechanics +
Footnote †: journal: Applied Sciences  
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**Flat rupture discs** are inexpensive to manufacture and are particularly suitable for applications with a static or quasi-static load characteristic. They require minimal installation space and predominantly maintain their flat profile throughout pressurization. This type of rupture disc is usually made of work-hardened metals with a stress-strain characteristic of brittle materials to ensure a precise response without significant plastic deformation. The compressive load from pressurization is mainly dissipated by normal and shear stresses before the rupture disc bursts. Examples of flat rupture discs are illustrated in Figure 2.  
**Forward acting rupture discs** are made exclusively of ductile metals and have a dome shape that is created by an hydraulic or pneumatic bulge-forming process. In the forward acting configuration of rupture discs, the dome faces away from the process to be protected, leading to tensile stresses in the metallic rupture membrane. Therefore, this type of rupture disc is also referred to as a tension-loaded rupture disc and is suitable for a variety of compressible and incompressible fluids. Although flat rupture discs do not have a dome, they are also subjected to tensile stresses when pressurized and are often assigned to the category of forward acting rupture discs. Most forward acting rupture discs are installed in systems with an operation ratio of around 80-85% [5]. This value indicates the ratio of the maximum allowable operating pressure to the lower limit of the bursting pressure of a rupture disc and can therefore be interpreted as the degree of utilization. In the forward acting regime, rupture discs work according to the so-called fail-safe principle, meaning that they can fulfill their safety function even if their are installed vice versa, as the side under pressure responds earlier than the side under tension (provided that no additional vacuum support is installed). Forward acting rupture discs transfer the pressure load mainly into normal stresses within the membrane plane, resulting in a plane stress state. This enhances their ability to withstand deformation, making them especially well-suited for applications that involve cyclic loading regimes. Figure 3 shows an exemplary overview of typical designs of forward acting rupture discs.