The phrase "perpetual struggle" is correct and usable in written English.
You can use it when you want to describe a long-lasting, difficult, and seemingly never-ending battle or disagreement. For example: "The couple was locked in a perpetual struggle, unable to find any common ground on which to base a compromise."
Quotations are in a perpetual struggle for survival.
Two defensive fortifications remain from medieval times, a legacy of the city's perpetual struggle against invaders.
One can also see Richard Ford's "Rock Springs" and Tobias Wolff's archipelago of perpetual struggle.
"All his rhetoric was the rhetoric of war, of confrontation and of perpetual struggle.
But basically, he seems to be in a perpetual struggle to answer the question of "What Would Reagan Do?".
Even an imperfect shield law would restore a little balance in the perpetual struggle between necessary secrets and democratic accountability.
A quite amazing triptych, given Southampton's perpetual struggles against relegation during this period, and United having become firmly established as the best team in the land by some considerable distance.
Given the perpetual struggles in this nation with expanding waistlines, and the apparent popularity of diet sodas, I would have expected that at least half the population would routinely try to cut calories by choosing what scientists call non-nutritive sweeteners in place of caloric sweeteners like sugar (sucrose) and high-fructose corn syrup.
In those perpetual struggles, he found his contentment.
I find that in perpetual foundations, there can be a constant struggle between the needs of the present generation and the wishes of the original donor.
(Orwell was on the humanist side, of course — basically an unmetaphysical, English version of Camus's philosophy of perpetual godless struggle).
