The effect of nanosecond pulse width on the breakdown strength of polymers

This paper reports the results of experiments to investigate the effect of nanosecond pulse width (τ) on the breakdown strength (E
_BD
) of polymethyl methacrylate and nylon 6 and derives a negative power relationship for E
_BD
with respect to τ. Using the enlargement law and the Weibull statistical distribution, the theoretical negative power law for E
_BD
with respect to τ is deduced. By reviewing and comparing the relevant experimental results, it is concluded that the physical nature of the pulse width effect on E
_BD
is related to the formative time lag and to the value of E
_BD
within the maximum formative time lag t
_{f_max}
. When τ<; t
_{f_max}
, the negative power law holds true. When τ>t
_{f_max}
, E
_BD
becomes independent of τ, and an upper limit is found for this independent relationship. The optimum power exponent for the negative power law of E
_BD
with respect to τ is 0.2-0.4.