Hello, I would like to know the force that can be tolerated by a surface before bursting under the effect of a stress. It is a hollow blister in which a volume of air is enclosed and which is sealed on the outer surface of 6.5mm in width. How much force would be required for the expansion of the air inside the blister to create the burst? 2 sizes exist. The sealed area is the perimeter noted by the black arrow
THANK YOU
Does F=p x s (F: force; p: pressure; s: surface area of pressure application) help you?
Hello @Elisabeth TAVARD_1
1°) it is not a force but a pressure (as @stefbeno says implicitly). In addition, you say (a surface before bursting under stress) which includes or excludes violent and voluntary impacts, on the side of the blister (your B1 cut)
2°) If we use the law of ideal gases, it says that the temperature of a given quantity of gas is proportional to the volume V times the pressure P. At a constant temperature, if we compress by a factor of 4 (we go from the atmospheric pressure 1 kg/cm2 to 4 kg/cm2), then the volume is divided by 4.
Which means how to bring in compressed air at 4 bars or more precisely how to obtain 4 bars of pressure from only less than 3 cm3 at the PA at the start.
3°) Why talk about an explosion when in the best case you will have a pressure de-compensating leak.
Explanation of 3°: your blister pack is probably 250 μ thermoformed PVC for the container and non-thermoformed PVC for the lid.
The lid cannot be welded in three ways, either by ultrasound, or in high frequency but not usual because of arc flashes, or as for blister packs on cardboard by an iron-on coating.
This means that if you take the iron-on coating, it is the one that will be the least resistant to anti-theft tearing and does not withstand pressure above 2 bars.
We are therefore left with ultrasonic welding, which has the disadvantage of modifying the thickness of the PVC, especially in the corners, which is the ideal weak point to generate air leaks if we manage to put compressed air in the closed volume.
So either the object contained in the blister contains a product that under certain conditions of temperature or shocks will generate a gas that will be compressed for lack of space between 2 and 5 bars, or the object contained is inert in the sense that it is unable to generate the slightest pressure.
If we summarize if no pressure then no leak (explosion to use your term), or if you get a very significant pressure, you will have a tear and therefore a sudden leak or a mini noise comparable to a paper bag being slapped between your hands. Just enough to startle a cat.
Kind regards
Hello @ All
You will notice that I did not understand the connection between the question asked and SolidWorks nor why this question is asked on our best forum.
On the other hand, I appreciated the quality of the contextual information provided (I didn't say blurry outside the image) to help us answer the question asked.
;-) ;-)
Kind regards
My dear @Zozo_mp, I admire the time you took to make your answer, I had kept the same conciseness as the question. On the other hand , you forgot the case of the release of steam linked to a microwave reheating, and there we manage to make beautiful "booms" with automatic artistic decoration of the walls of the said oven.
