Containment in a technical sense means:
• a safety device in nuclear power plants, see safety container
• the compressor and turbine casing of an aircraft jet engine
• the isolation of a manufacturing process or hazardous location, e.g. for employee protection
Containment is thus the process of containing something dangerous or unpleasant and includes the act or process of keeping the dangerous or unpleasant under control in a specific area or location.
For this purpose there is also the term enclosure, i.e. a housing or a room which must not be penetrated by hazardous particles to protect the environment.
An exploding tank, a broken rotor, detached turbine blades, fragments of a grinding wheel, liquids, gases should therefore not penetrate the enclosure or test chamber during a controlled test or failure of components under pressure, acceleration or centrifugal force.
In the case of rotating parts, containment is understood to mean the protection against failing, rapidly rotating components by means of appropriately dimensioned housings. If, for example, a grinding wheel breaks, the fragments must not leave the protective housing. This applies equally to turbochargers, engine blades, compressor blades and rotating shafts. If an aircraft’s engine blades become detached, the fragments must not penetrate the engine casing in order to protect passengers and the aircraft.
Accelerated Parts and Liquids
These can be machine components such as robot arms that do not leave the protected area in the event of a failure of the control system. If the robot arm hits the safety housing with a certain, defined energy, there must be no puncture. Accelerated liquids are a special case. This is used, for example, for the simulation of tank sloshing. Baffles can be used to prevent liquid from destroying the tank.
Parts Under High Pressure
If pumps, hoses, tanks or containers fail, e.g. during bead breaking or bursting tests, the fragments, but also the media with which the pressure is generated (e.g. water, oil or air or gas) must remain in the test chamber, which should not normally be destroyed.
The pressure vessel standards prescribe corresponding tests in test chambers.
When firing at armoured vehicles or buildings, the projectile must not reach the area to be protected. The protection of people by bulletproof vests can also be considered. Here, the bruising or breaking of ribs due to the impact can be considered.
Explosions are a special case of pressure loads, which we can calculate using the same methods. The pressure load is described here mathematically as a temporal pressure wave. This is an extension of the quasi-static pressure shock resistance test, which we can of course also cover mathematically.
Merke & Partner is a world leader in the calculation and design of test chambers.
We use a wide variety of methods and can also take the behavior of media (water, steam, gas, air) into account in the calculation.
Why are such simulations performed?
Containment costs money and above all must be safe.
The objective of the simulation is the verification or optimization / design of the containment, the armoring, the chamber, so that it is ensured that the containment is safe, but also not over-dimensioned.
The physics involved in this type of simulation is very complex, since it involves highly dynamic processes with different media (solids, liquids, gases), in which the behaviour of the materials (strain rate dependence, fracture behaviour, triaxity) plays a particularly important role. The energies released are sometimes enormous and often correspond to luxury class cars at 200 km/h speed.
In video 1, you can see a test chamber in container design, where hydrogen cylinders are tested with water until they break. The sacrificial plates, which hang on chains like a shower curtain, can easily be replaced if necessary in case of damage.
Video 1: Burst simulation of a hydrogen container in a test container
Compressed gases contain additional energy compared to liquids, which are comparatively incompressible. However, the compressibility at high pressures also plays an important role for liquids and must not be neglected.
This topic is predestined for us, as we have and will continue to have a long-standing lead here.
Many well-known manufacturers of test chambers, hoses, turbochargers, shredders etc. rely on our expertise in this area.
We are happy to help you build more efficient test chambers, enclosures, housings, buildings, armour or protection devices without wasting money.
Video 2 shows the burst behaviour of a vacuum generator used for cabin ventilation in aviation. The speeds at rupture are about 25,000 rpm.
The containment fails, the fragments of the axial field rotor penetrate the housing. Several optimization loops were necessary until sufficient protection was provided.
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