Strength enhancement in composite insulation-a phenomenological study

The layered build-up of composite electrical insulation (EI), and the introduction of barriers in gaps, are well-known techniques of HV EI engineering. Such composite EI have increased electrical short-term and long-term strength as well as better mechanical, thermal, etc. performance, plus certain technological advantages. In this paper I derive the rules of stress distribution in composite EI. To keep the reasoning maximally simple I assume a plane geometry