Use of granular materials to improve the bearing capacity of the housings of apparatus

As we know [1], granular materials can be used as a structural element in high-pressure apparatus; this makes it possible to lower their metal consumption considerably. Let us examine the possibility of the use of granular materials in apparatus operating under an external pressure. An illustrative diagram of the housing of such an apparatus [2] with bearing shell 1, which is strengthened by layer 2 formed from a granular material and which is enclosed in elastic impermeable shell 3, is shown in Fig. 1. We can assume that in a deformable granular medium, circular arch structures, which reduce the radial pressure on the bearing shell, will be formed under an external pressure transmitted through the impermeable elastic shell. According to continuum mechanics, the relationship between radial and tangential stresses, which are principal stresses (mass forces are considered negligibly small), is defined by the statics equation, which depends on the shape of the body formed from the granular material and assumes the following form: