Done Projects

Descriptions :

There are a variety of surgical methods for treating meniscus root tears to restore meniscus proper function. This study aims to propose a biomechanical testing methodology in order to evaluate meniscus extrusion under cyclic loading. The load was applied in three steps to simulate the meniscus extrusion in the healthy status, injured situation and post-operation conditions. This study evaluated 3 differents surgery methods that one of which is a new method

Keywords :

root tears, meniscus extrusion, sutures, meniscus root, biomechanical test

Supervisors :

Elham Asheri-Saghavaz

Students :

Ahmad Hedayatzadeh , Amirreza Rezaeepazhand,  Amirhossein Borjali, Navid H.Z. Abedini

Publications :

A biomechanical methodology to evaluate pre- and post-operation meniscus extrusion

Descriptions :

A three-dimensional finite element (FE) model of the heel and shoe sole was developed to analyze the effects of using materials with different Poisson's ratios for midsole on energy absorption and impact shock in the heel area during walking. The heel model was obtained from CT-scan data. The FE model was verified using Anybody software for barefoot with data obtained from gait analysis. Sole layers and plantar soft tissue were modeled, and five different Poisson's ratios (-0.4, -0.2, 0, 0.2, and 0.4) were compared for the midsole layer. In order to obtain the contact force, experiments were performed on a force plate using shoes with either auxetic or conventional midsole layer. Rayleigh damping theory was used to simulate viscous damping behavior in the midsole layer. The results showed that for materials with the same Young's modulus, there was less compression, energy absorption, and viscous dissipation energy in the auxetic model in comparison to the conventional model. However, when compressive strains of sole layers were the same (i.e., by changing Young's modulus), more energy absorption (about 9%) was observed for the midsole with negative Poisson's ratio with respect to the conventional midsole layer.

Keywords :

Auxetic; Finite Element Analysis (FEA); gait analysis; strain energy; shock absorption.

Supervisors :

Professor Amir Nourani

Students :

Mahdi Daei-Daei ,Mohammadmahdi Honarmand

Publications :

A. Nourani, M. Daeidaei, and M. Honarmand, “Finite element analysis of the performance of auxetic materials as shoe midsole, using force plate’s data”, Proceedings of 27th Annual International Conference of Iranian Society of Mechanical Engineering (ISME), Tehran (Iran), April 30 – May 2, 2019. coi

Descriptions :

The ability to predict the fracture strength of solder joints would be a useful tool to assess the reliability of electronic devices. The vast majority of studies in the literature have dealt with the qualitative reliability testing of solder joints, while only a few studies have tried to give fundamental fracture property data that would be useful for fracture load prediction purposes. In this project, mode І critical strain energy release rate at crack initiation, Jci, of SAC305 solder joints between two copper substrates was measured using double cantilever beam (DCB) specimens at a strain rate of 0.03 s-1 as a function of bond-line width (i.e. joint size in the out-of-plane dimension), solder thickness, copper adherends thickness, suface roughness and joint arrangement.

Keywords :

Fracture behavior, solder joint, critical strain energy release rate, loading arm, load sharing, joint size/geometry.

Supervisors :

Professor. Ahmad Assempour

Assistant Professor. Amir Nourani

Students :

Sadegh mirmehdi, Mohammaamahdi Honarmand, Farid Soroush

Publications :

1- Influence of Joint Arrangement on the Fracture Behavior of Lead-Free Solder Joints.

2- Predicting Crack Initiation of Solder Joints with Varying Sizes Under Bending.

3- Predicting fracture of solder joints with different constraint factors.

Descriptions :

A medical image of the tibia has been modeled in Mimics to investigate the effects of implant's geometric parameters on mechanoregulation of bone in high tibia osteotomy. The stress analysis of bone and implants and the micro-motions under mechanical loads has been investigated in Abaqus software. The ultimate goal is to provide the proper environment for bone formation while maintaining system stability. Based on previous work, the Tomofix implant structure has been studied as the most suitable implant. Increasing the number of holes and shortening the tomofix implant are the modified parameters in this study. The results show that increasing the number of screws helps Tomofix improve bone formation and bring acceptable stability.

Keywords :

Implant, Mechanoregulation, Bone remodeling, FEM, Optimization, Biomechanics, Micro-motion, Stress shielding

Supervisors :

Dr. Amir Nourani

Students :

Ali Behbahani

Descriptions :

Variability in the values of gait cycle parameters is a measure of walking stability. Mental or physical disabilities usually manifest themselves in hand or foot movements. In this study, using the upper body acceleration data which was obtained from Inertial sensors, the variability of gait cycle parameters was investigated. Then, the reproducibility of the parameters in healthy individuals in this method was compared with the gold standard methods for healthy and sick elderly (at risk). The results showed that the step time parameter can be a suitable criterion as a standard method for separating healthy and sick people (at risk) as it had a good correlation with gold standard methods. Also, the variability of the step time parameter with a slight error compared to the gold standard methods can be considered as a suitable criterion; however, the variability of the swing time parameter showed a significant difference compared to the conventional methods. Investigating the variability of acceleration size in three anatomical directions showed that the acceleration in the anterior-posterior, and lateral directions had the highest repetition among healthy subjects.

Keywords :

Variability at the gait cycle, Inertial sensors, Upper body acceleration, Fall prediction, Variability at the upper body acceleration

Supervisors :

Dr. Amir Nourani

Prof. Farzam Farahmand

Students :

Ali Behbahani

Descriptions :

Auxetic metamaterials have a negative Poisson's ratio (NRP), and this irregularity makes them suitable for numerous engineering applications, such as enhancement in indentation resistance and energy absorption. The Poisson's ratio of re-entrant auxetic structures is highly strain dependent, and it can remain negative exclusively over a specific strain range. In re-entrant hexagonal cells, the Poisson's ratio increases with strain, surpasses zero, and becomes positive, which exterminates the auxetic characteristics of the structure. This study proposes a parametric analysis based on the structure geometry and performs a multi-objective optimization based on the auxeticity range and Poisson's ratio. A design of experiment (DOE) was carried out using the Taguchi method to find an empirical relation between Poisson's ratio and strain. The finite element method (FEM) was deployed to investigate the mechanical response of re-entrant structures to tensile loading. Using a statistical analysis, geometrical parameters were ranked based on their influence on Poisson's ratio. The empirical relation between the geometrical parameters, Poisson's ratio, and the auxeticity range was obtained to achieve the best geometrical configuration of the re-entrant structure using a genetic algorithm optimization. Finally, the best combination of geometrical parameters to increase the negative Poisson's ratio and extend the auxeticity region was represented.

Keywords :

Auxetic metamaterials, Negative Poisson’s ratio, Re-entrant hexagonal, Finite element analysis, Optimization

Supervisors :

Dr. Amir Nourani

Students :

Ali Behbahani, Sharif Sha'bani