Suppose I have an elastomeric specimen from a material sample known to have dielectric strength of, say, 15 kV/mm, as informed by previous dielectric strength testing. If I were to repeatedly subject this specimen to 12 kV/mm, or some other significant fraction of the known dielectric strength, will the specimen eventually experience premature dielectric breakdown, independent of any effects that might occur due to aging?

Are there any books or papers that might provide insight to this question?


1 Answer 1


It depends.

When the limit (15 kV/mm) is given for the material, it should indicate severe transport mechanisms, like:

  • electrons accelerated
  • creating free ions on their path
  • accelerating said ions
  • creating even more damages on atomic, micro and macro level
  • from avalanching bombardments.

However, sometimes such limits are given for the device, which can include the measurement itself. Then it will be a mixture of mechanisms. E.g. it might spark in air, while its structure is still intact (which is a way to protect devices, BTW: let them spark in air early enough).

Unless you manufacture the elastomer yourself there should be a datasheet or additional information available from its manufacturer or supplier.

Breakdown curves will be far from ideal analytical functions. As a rule of of thumb it (the current flowing) can vary between a power law ($V^x$) to exponential ($e^{f(V)}$) BEFORE breakdown.

Lifetime depends on many factors, with temperature being a major, and often exponential, factor. But it also depends on other ways of introducing mechanical/structural harm during operations, e.g. by excessive bending, strong vibrations at the torn-appart-frequency/resonance or similar. Look e.g. for accelerated lifetime testing.

If you want to obtain a safety factor, you'd probably need a mean (i.e. grim) stress test under hellish conditions.

  • $\begingroup$ Thanks for the response! I'm specifically interested in the material. If I want to read up on those transport effects mentioned, can you point me to a book? Also, are there any electrically induced effects to the material that might happen before breakdown occurs? $\endgroup$
    – Skyglare
    Mar 31, 2023 at 1:04
  • $\begingroup$ Thanks. Sorry, I can‘t. Did you try scholar.google.com? $\endgroup$
    – MS-SPO
    Mar 31, 2023 at 5:40

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