The Universal Yield Limit: Relativistic Mass as Structural Failure of the 2D Manifold

Special Relativity posits that mass increases infinitely as velocity approaches the speed of light ($c$), making it impossible for baryonic matter to reach this limit. This paper provides a deterministic mechanical derivation for this limit using the Universal Space Theory (UST) framework. We propose that $c$ is the physical saturation velocity of the 1D Stochastic String Network (SSN). We demonstrate that "relativistic mass" is the measure of increasing internal pressure required to displace the 1D medium at high velocities. Furthermore, we prove that matter cannot reach $c$ because the 2D manifold skin reaches its structural yield point (rupture threshold) at $v < c$, resulting in the dissolution of the 3D inclusion into radiation. This resolution provides a purely mechanical foundation for the GZK limit and particle fragmentation.