Finite Element Analysis to Study Tensile Strength Differences between Free and Attached Ear Lobules.

Recurrent ear lobule deformity is a chronic condition with aesthetic implications. The problem is normally addressed by certain improvisations of the traditional lobuloplasty technique. These include introduction of autologous tissue components like cartilage pieces to improve the structural integrity. Certain authors also advocate a different site for repiercing of the ear hole away from the lobuloplasty scar. Our study tries to understand the differences in the tensile strength between free and attached ear lobules, using finite element analysis. Eighteen healthy female volunteers with attached (eight subjects) and free ear lobules (10 subjects) were chosen, and the lobules were scanned using Artec 3D scanner. The model was then converted to free form or attached form (opposite to the form in which it was present originally) by decreasing or increasing the area of contact using geomagic software. Finite element analysis was then performed on both the models, and their yield max and, hence, the maximum load at the yield max at 0.7 strains according to previous studies were estimated and compared. The yield max and the corresponding load were found to be lesser in the free variety than in the attached variety. This experiment helps us to understand that when a structural difference in the ear lobule surgically may bring about a change in the tensile strength of the lobules. However, further clinical trials are required to clinically translate the same.

Biomechanical analysis of Instrumented decompression and Interbody fusion procedures in Lumbar spine: a finite element analysis study.

Interbody fusions have become increasingly popular to achieve good fusion rates. Also, unilateral instrumentation is favored to minimize soft tissue injury with limited hardware. Limited finite element studies are available in the literature to validate these clinical implications. A three-dimensional, non-linear ligamentous attachment finite element model of L3-L4 was created and validated. The intact L3-L4 model was modified to simulate procedures like laminectomy with bilateral pedicle screw Instrumentation, transforaminal, and posterior lumbar interbody fusion (TLIF and PLIF, respectively) with unilateral and bilateral pedicle screw instrumentation. Compared to instrumented laminectomy, interbody procedures showed a considerable reduction in range of motion (RoM) in extension and torsion (6% and 12% difference, respectively). Both TLIF and PLIF showed comparable RoM in all movements with < 5% difference in reduction of RoM between them. Bilateral instrumentation showed a more significant decrease in RoM (> 5% difference) in the entire range of motion except in torsion when compared to unilateral instrumentation. The maximum difference in reduction in RoM was noted in lateral bending (24% and 26% for PLIF and TLIF, respectively), while the least difference in Left torsion (0.6% and 3.6% for PLIF and TLIF, respectively) in comparing bilateral with unilateral instrumentation. Interbody fusion procedures were found to be biomechanically more stable in extension and torsion than the instrumented laminectomy. Single-level TLIF and PLIF achieved a similar reduction in RoM with a < 5% difference. Bilateral screw fixation proved biomechanically superior to unilateral fixation in the entire range of motion except in torsion.

Source codes and simulation data for the finite element implementation of the conventional and localizing gradient damage methods in ABAQUS.

This data article presents the source codes and obtained simulation data for running numerical fracture simulation in the commercial finite element package, ABAQUS. The computational models implemented through these source codes pertain to the conventional and localizing gradient damage method which are used for the modelling of the fracture phenomena in the components and structures. For a detailed description refer to "A comparative study and ABAQUS Implementation of Conventional and Localizing Gradient Enhanced Damage Models [1]". The implementation is carried out using a feature in the ABAQUS software called the user defined subroutines. The subroutines are a set of coded files which are used to implement any newly developed computational models depicting actual physical phenomena which are not already available in any commercial software. The user subroutines used in this implementations are UEL and UMAT. The present implementation is very user friendly in the sense that the user needs to just type a couple of commands in the ABAQUS command application to run the simulations. Moreover, the ability of the ABAQUS to run large scale simulations using a very sparse amount of computational resources enables researchers and engineers with limited resources to take advantage of a very advanced computational fracture simulation technique.