Human eye model
A three-dimensional FE model of the human eye has been made via the explicit dynamics finite element code LS-DYNA 970 (LSTC, Livermore, CA, United States) [30]. The morphological characteristics of the human eye (a normal/healthy male) along with intraconal and extraconal fats were obtained from Computed Tomography (CT). The donor declare his consent to use the CT images for medical research purposes. A total of 141 raw data images were obtained for the head with an especial focus on the eye. The data were analyzed and exported into the Digital Imaging and Communications in Medicine (DICOM) format. Subsequently, these data were imported into a Windows-based personal computer using MIMICS software (MIMICS 10.0, Materialise Inc., …show more content…
In this methodology, the energy of TNT was supposed to be abruptly released inside the front of detonation wave. Detonation process requires to model the movement of the products of detonation after they reach subsequent specific locations by the detonation wave front. Detonations have a faster reaction zone than the sound speed. Progression of blast waves has been presumed to be perpendicular to the corneal surface unless differently specified and the eye in primary position, (i.e.: staring at the explosion). The surrounding air domain were modeled using Eulerian mesh. The explosive was modelled based on the Jones-Wilkins-Lee (JWL) equation of state (EOS) [35]. The EOS is in wide speared use owing to its straightforwardness and due to the fact that most high explosives are well modelled by this equation. The JWL equation allows a suitable approximation of overpressure, which has been widely used in numerical computations. The evolution of the explosive after ignition is described by JWL equation of state, *EOS_JWL, which defines the pressure …show more content…
In this model the ignition time of a particle in the explosive was equal to its distance to the ignition point divided by the detonation velocity. The *MAT_NULL material and *EOS_LINEAR_POLYNOMIAL equation of state in LS-DYNA were used to express the above constitutive relations. The interface of Euler and Lagrange elements at the detonation model were coupled using Arbitrary Lagrangian-Eulerian (ALE) method [36, 37]. This coupling method has the advantage that it gives complete freedom to create an optimal mesh for both the Lagrangian and Eulerian domains, compared to alternative coupling methods. The contact algorithm utilized in this study was ‘*CONTACT_ERODING_NODES_TO_SURFACE’, which is available in the LS-DYNA 970 [38]. A total of 120 μs were executed for simulation with a time step of 1 μs. The stress distribution in each region when the model was subjected to a high explosive detonation wave was simulated and measured by the post-processing software (LS-PREPOST of LS-DYNA) [39,
A three-dimensional FE model of the human eye has been made via the explicit dynamics finite element code LS-DYNA 970 (LSTC, Livermore, CA, United States) [30]. The morphological characteristics of the human eye (a normal/healthy male) along with intraconal and extraconal fats were obtained from Computed Tomography (CT). The donor declare his consent to use the CT images for medical research purposes. A total of 141 raw data images were obtained for the head with an especial focus on the eye. The data were analyzed and exported into the Digital Imaging and Communications in Medicine (DICOM) format. Subsequently, these data were imported into a Windows-based personal computer using MIMICS software (MIMICS 10.0, Materialise Inc., …show more content…
In this methodology, the energy of TNT was supposed to be abruptly released inside the front of detonation wave. Detonation process requires to model the movement of the products of detonation after they reach subsequent specific locations by the detonation wave front. Detonations have a faster reaction zone than the sound speed. Progression of blast waves has been presumed to be perpendicular to the corneal surface unless differently specified and the eye in primary position, (i.e.: staring at the explosion). The surrounding air domain were modeled using Eulerian mesh. The explosive was modelled based on the Jones-Wilkins-Lee (JWL) equation of state (EOS) [35]. The EOS is in wide speared use owing to its straightforwardness and due to the fact that most high explosives are well modelled by this equation. The JWL equation allows a suitable approximation of overpressure, which has been widely used in numerical computations. The evolution of the explosive after ignition is described by JWL equation of state, *EOS_JWL, which defines the pressure …show more content…
In this model the ignition time of a particle in the explosive was equal to its distance to the ignition point divided by the detonation velocity. The *MAT_NULL material and *EOS_LINEAR_POLYNOMIAL equation of state in LS-DYNA were used to express the above constitutive relations. The interface of Euler and Lagrange elements at the detonation model were coupled using Arbitrary Lagrangian-Eulerian (ALE) method [36, 37]. This coupling method has the advantage that it gives complete freedom to create an optimal mesh for both the Lagrangian and Eulerian domains, compared to alternative coupling methods. The contact algorithm utilized in this study was ‘*CONTACT_ERODING_NODES_TO_SURFACE’, which is available in the LS-DYNA 970 [38]. A total of 120 μs were executed for simulation with a time step of 1 μs. The stress distribution in each region when the model was subjected to a high explosive detonation wave was simulated and measured by the post-processing software (LS-PREPOST of LS-DYNA) [39,