Most coax cable is purposely made to withstand a significant amount of abuse. Most bending and denting will hardly at all result in a measurable impedance change at the abused point.
In terms of an impedance change at the "deformed" area, when you deform a round cross-area it becomes oval like, the oval shape thins at two points but also widens at two other points. So the averaged capacitance from center to shield at the deformed point is hardly changed. For the center conductor's inductance, note that you are unlikely to change this as it is very much protected at the center of the material layers. Even when coiled the center conductor does not see (magnetically) the other close conductor loops due to the shielding.
If you start to abuse the cable to the point where the conductive shielding becomes significantly damaged or cut then that should begin to produce a measurable reflection. You might test this by running the reflection test while slowly crushing the cable in a strong metal twist clamp or vise. You will likely find that the cable needs to be significantly crushed before seeing a reflection.
If the need is to create a cable that detects a mechanically altered point try using a simple piece of flat cable. On it's own a conductor in this type of cable is only partially shielded by the nearby conductors. A sharp bend or other damage to this type of cable may be much more detectable. Using two or more flat cables laying over each other might make an even more sensitive detector of a point that is being crushed or abused.