At what pressure is whipped cream stored in a can

There are two levels to this question. If you are using modern whipping cream as a starting point, then the trick for a longer lasting whipped cream is stabilization. If this is some farm bought milk you are skimming the cream from, then you have the additional problem that your cream is not fatty enough. Modern creams are concentrated with a centrifuge.

To get good whipped cream, whip it cold until it doubles in volume and you get firm peaks. Stabilize the whipped cream by hanging it in a cheese cloth in the refrigerator or by adding gelatin.To use the gelatin, dissolve 2 teaspoons of unflavored gelatin into 2 tablespoons of cold water. Work out the lumps. After the gelatin expands, mix in a quarter cup of cream and heat the mixture to dissolve the gelatin.  Cool over ice and mix a bit. Complete 2 cups of cream and proceed as you would to finish your whipped cream.

I don't think so. In the mayonnaise case, all that has happened is the fat has come out of emulsion and gathered together again, so you can re-emulsify it. In the whipped cream case, you've started to create large fat crystals (butter). I guess technically it might work to heat it up to melt the butter, re-emulsify it into cream and then beat it again, but I don't think it would be worth the effort. You could go ahead and finish churning it into butter and buttermilk if you want to avoid wasting the cream.