Optimization of Passive Safety Systems


 

Research Projects:

 

Human Body Modelling For Safety and Crash Analysis

Researchers: Danial Sharifikia, Alireza Noamani, Vahid Dehghan Neyestanak, K. N. Toosi University of Technology

Mitral valve simulation remains a controversial topic as a result of its complex anatomical structure and mechanical characteristics, such as it's nonlinear material properties or time dependent loading conditions. Here, the dynamic behaviour of human Mitral valve has been simulated in response to normal physiological conditions in a cardiac cycle, considering the anisotropic nonlinear behaviour of Mitral leaflets.  The Aim of the current study is to simulate human Mitral and Aortic valve surgical treatments and repair procedures in order to investigate the outcome of different treatment procedures on the Mitral valve behavior before open heart surgery. Mitral regurgitation, as the most common Mitral dysfunction, accounts for almost 70% of common Mitral dysfunctions. Edge-to-Edge repair is a repair technique in which the Mitral prolapse is treated by the attachment of the prolapsing segments to the opposing leaflet. Effects of extremely accelerated environments on human body functionality range from temporary loss of vision and consciousness to damage to human organs. Mitral valve behaviour in high speed crash accidents has been simulated by conducting a numerical study and it has been observed that besides different stress-strain patterns generated on Mitral leaflets, abnormal deformed configuration may rise from accelerations which can affect the cardiovascular system.

 

 

  • Developing Computational Model for Evaluation of Brain and Spine Trauma in Vehicle Crashs

Based on complicated modelling problems, in this study, a finite element model of the human head has been developed in order to evaluate different types of brain damage. First 233 sections MRI images of the head of a 42 years old man were prepared. For image processing operation, the images were entered in the software Mimics software. The geometric models of Skull, Meninges and brain were extracted. For geometric editing, each of these models was entered into 3-Matic software. Using 3-Matic software, Multi-Stage editing operation, surface smoothing, and removing the border interaction was conducted.

 

  • Crash Injury Analysis of Knee Joint Considering Pedestrian Safety

The aim of this study is first to provide an accurate Finite Element model of the knee joint and second to investigate lower limb impact biomechanics in car-to-pedestrian accidents and to predict effect of parameters such as collision speed and height due to the car speed and bumper height on knee joint injuries, especially in soft tissues such as ligaments, cartilages and menisci. A 3D finite element (FE) model of human body knee joint is developed based on human anatomy. The model consists of the femur, tibia, menisci, articular cartilages and ligaments. Material properties of bones and soft tissues were assumed to be elastic, homogenous and isotropic.

 

 

In this research, a 3D constitutive model which is based on the hyper elastic behavior of skeletal muscle and energy function has been presented. By using the derivatives of such energy function for defining the Second Piola and Cauchy stresses, the model could describe the inactive behavior of skeleton muscles. The applied constitutive equations are an efficient generalization of Hamphury's model for the inactive behavior of skeletal muscle. In this paper by using a 3D model, different modes of deformations of skeletal muscle  such as simple tension, biaxial and shear tests have been investigated and material properties constants for each mode of deformation has been optimized by Genetic Algorithm. Finally the results of the model simulations of each mode are compared with those obtained from experimental tests. Also, the model results are compared with the ones from two well- known hyper elastic Ogden and Mooney-Rivilin models in order to show the priority of the new developed 3D model.


  

 

Thermoelectric Power Generator for Energy Harvesting from Waste Heat

  Researchers: Keymand Kiani, Maryam Abuali Shamshiri, Negar Izadipoor ,K. N. Toosi University of Technology  

An Automobile TEG-System has been designed and constructed which utilizes TEG modules in order to recover a portion of waste heat energy of engine through exhaust system. The TEG-System has the capacity of 48 40x40-Modules and has been tested on a 4-stroke petrol engine with the capacity of 1300cc. The system output power depends on various parameters, ranging from system characteristics to the engine charasteristics and its load and speed.

 

 

 

Thin-walled Structures for Crashworthiness Optimization

Researchers: ,K. N. Toosi University of Technology

To achieve an acceptable level of safety, thin-walled structures have become widely used as an efficient and applicable means to their high value of energy absorption characteristics and their light weight. New developed thin-walled tubes have been introduced for improving energy absorption characteristics. Bi-tubular, Corrugated, Composite and Conical-cylindrical Tubes in Axial and Oblique Loadings have been analysed and optimized via numerical and experimental methods.

 


 

Additively Manufactured Architected Cellular Materials for Adjustable Mechanical Properties

Researchers: ,K. N. Toosi University of Technology

Elastic-plastic behavior of regular and functionally graded additively manufactured porous lattice structures made by a double pyramid dodecahedron unit cell is investigated. The elastic moduli and also energy absorption in terms of specific energy absorption and maximum stress are evaluated via finite element analysis. Experimental tests are performed in order to validate the numerical results which showed good agreement between experimental and finite element results.

 

Topology optimization method is used to develop new and efficient unit cells for creating additively manufactured porous lattice structures having improved mechanical performance. Two types of unit cells including solid and thin-walled shell type is obtained for generating desired lattice structures.

 

A novel radially graded porous biomaterial is introduced in the current study. Mechanical properties of the proposed structure are derived and validated through experimental test and numerical FE modeling.

 

 

Faculty of Mechanical Eng. of K. N. Toosi University of Technology
Vanak Square, Molla-Sadra, Pardis
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1999143344 TEHRAN
IRAN (ISLAMIC REP.)
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