The phrase "a stiffening" is correct and usable in written English.
It can be used to describe a process or action that causes something to become rigid or firm, often in a physical or metaphorical sense.
Example: "The sudden drop in temperature resulted in a stiffening of the metal, making it more difficult to work with."
Alternatives: "a hardening" or "a tightening".
A one-piece mold, prepared for a dagger, could have a groove for most of the length of the cavity to provide a stiffening rib on one side.
The small handsaws were sometimes backed with a stiffening rib to prevent the buckling of thin blades; today's backsaw still carries the rib.
To be fair, the allegory isn't as glibly intrusive as that makes it sound, but it has a stiffening effect on the narrative, shifting it from the dramatic to the essayistic.
Ms. Davisson's style of painting, on raw canvas rather than on canvas primed with white gesso, a stiffening agent, "adds a gentle look," he said, and helps her capture "the character, the essence of a person".
Moreover, surface energy can induce a stiffening effect i.e. reduces the nano-wire deflection.
A stiffening effect with compression rate is observed especially in directions closer to the muscle fibres.
Without loss of generality, throughout the manuscript we will consider the case of a stiffening nonlinearity with (varepsilon>0).
This indicates that binding site reoccupation has a stiffening effect lowering the mobility of nearby nuclei.
A stiffening factor is introduced into the hysteretic differential equation which enables the distinction between virgin loading and reloading.
Money is cheap, companies are flush with cash, job growth has somewhat picked up after a host of setbacks, and there are signs here and there of a stiffening economic comeback.
Meanwhile, the importance analysis of a stiffening rib of the wing leading edge in a certain aircraft also verifies its good engineering applicability.
