LAUSR

In this paper, we have analyzed the role of a viable f(R,T) model, i.e. f(R,T) = R + αR2 + γRn + λT, while exploring the unstable regions of cylindrically symmetric gravitational source, where, R and T correspond to the Ricci invariant and trace of energy momentum tensor, respectively. The matter distribution is considered to be anisotropic and gravitating system evolves under zero expansion condition. The collapse equation of cylindrical star has been obtained by applying perturbation scheme on modified field equations and conservation equations. Dynamical instability has been discussed in N and pN regimes, stability constraints have also been developed. We found that adiabatic index Γ is meaningless for the discussion of stability of gravitating sources carrying expansion-free condition, and stability variations are determined by physical properties of the fluid.