Electrostatic force distribution in a multi-layer dielectric tested by means of the PEA method

The principle of the Pulsed Electro Acoustic (PEA) method, for measuring space charge in insulating materials, is discussed in case the test object is a multilayer flat sample. In particular, the evaluation of the electrically induced mechanical stress a solid dielectric combination experiences when tested by means of the PEA technique is proposed in this paper. In the literature, this topic has been addressed in two different ways in case of single layer dielectrics, both leading to the same conclusion. However, when applied to multi-layer dielectrics, the estimated force distributions are dissimilar. In order to clarify this point, a two-layer specimen was tested in a PEA test set-up. A comparison was made between measurement results and calculations. A force distribution, which is in between the two differently calculated distributions, was measured.