. In this paper, the finite element modeling with Non-linear geometry and static Riks analysis for an elastic rod was employed to estimate the 2D and 3D Elastica shapes under post-buckling condition. A 3D Elastica forms when two equal moments in opposite directions are employed in addition to a pair of balancing forces. The studied case is in ill-condition and the Riks method is useful for unstable cases and can speed up convergence in ill-conditioned problems that do not exhibit instability. In fact, the modified Riks method is chosen because the straight rod exceeds the critical pressure load and post buckling occurs. The 3D beam element type is chosen for this case and material is assumed perfectly elastic and homogeneous. The circular cross section about 5mm in diameter is utilized. A Beam element type is chosen due to small ratio of cross-section radius to the rod length. Then, a photo of a buckled elastic rod is taken by a digital camera and this Elastica shape is assumed as default data in finite element software. The static method with nonlinear geometry is used for this analysis in ABAQUS software, since time has no significant effect on the solution and large rotation is applied. Static method that is implicit, accurate and limited to simple issues without complex contacts is used in this study. A twisted shape of Elastica was investigated through applying a pair of equal unbalancing twisted torques to the ends of a 2D Elastica shape using finite element analysis.. In fact, the torques’s make the 2D Elastica shape twist into z direction which is similar to a warp-knit loop. The Elastica shape turns on 3D path and the axial of the rod is rotated and out-of-plane deformation happens as a result of exertion torsion torques. The experimental aspect ratios for basic and twisted Elastica shapes are obtained and compared with those of theoretical ones. The theoretical and experimental results show good agreement. Therefore, this shape of Elastica could be considered suitable for warp knitting loop definition. The obtained loop can be used in the warp-knitted fabric models under external or internal forces and yarn friction, extension and compression effects could be taken into consideration in future ABAQUS models. The FEM is an appropriate method in this study because the usability of the loop modeling results in the warp-knitted fabric models under different conditions. In this study, a single-bar warp knitted fabric is simulated under low strain condition and 3D model of loop is used as the overlap of this simulated fabric. The Dynamic Explicit method is used and the model results are compared with the real fabric results at low strains. The model results and the fabric results correspond well with each others.