Finite Element Simulation of Needle Insertion into Cornea

Mechanical properties during needle puncturing cornea are tested by using a micro-force material tester.The relationship between displacement and axial force is obtained for No.2 suturing needle under normal intraocular pressure,when the needle is puncturing cornea with a velocity of 1mm/s.A finite element model of needle puncturing cornea is established by linear triangular element,a new finite element algorithm of contact interaction between needle and cornea soft tissue is designed based on the theory of stick-slip.The relationship between displacement of needle-tip and needle-axial force obtained through testing is considered as boundary conditions,the iterative algorithm is used to solve the finite element simulation problem under the Matlab environment, needle puncturing cornea is successfully simulated in real-time.At the same time,the displacement drawing of needle-tip and the relation curve between displacement and needle axial force are numerically obtained.Compared with the testing results from experiment,the method is effective and significant for designing cornea-grafting robot and planning suturing manipulation.