Influence of distribution of contact pressure on leakage through casket

The questions of influence of the shape of contact surfaces on leakages through rubber seals in fixed connection of subassemblies of space technics are considered in the article. It is known from practice of operation of seals of various designs of space-rocket hardware that the shape of contact surfaces and consequently also the shape of diagram of stresses in a contact zone, considerably influences the leaks value. The design of test equipment and technique of leaks study through fixed face seal is offered. Object of research is the fixed face ring seal. During the tests into a ring rubber seal the ring indentors of various shape were pressed. The depth of introduction was regulated and measured with split-hair accuracy. Thus various variants of distribution of contact stresses on width of a contact area were modelled. The air was delivered under different pressure through a gas reducer in an internal cavity of seal and measurement of leaks was made. Experimental dependences of leaks value vs external pressure at various values of introduction of the peak into rubber are received. The developed finite-element models of three seals used in experiment with various shapes of indentors and program STAR has allowed to theoretically study distribution of stresses on width of a contact area. The result of this experimentally-theoretical work was creation of the new finite-element program for calculation of leaks through fixed rubber seals LEAKAGES, considering the shape of rubber seals, viscoelastic properties of rubber, including the relaxation and creep phenomenon. As a result of experimental researches on introduction ring indentors of different profiles into a rubber fixed gasket it was found that at the expense of shape optimization of indentor the leaks value can be lowered 10 times. The finite-element program for calculation of leaks which allows optimizing the shape of created rubber seals for the aerospace equipments is developed.