Biomechanical Modeling of Human Eye in Car Airbag Blunt Impacts During Accident: an Empirical Test and Finite Element Study

, M.Sc. Thesis Sharif University of Technology Shirzadi, Hooman (Author) ; Zohour, Hassan (Supervisor)

Abstract

Eye and vision are the most important tools and the perceptual sense of human. This important vital member is one of the most vulnerable organs of human body. For example in the United States 1.9 million eye surgery are being done yearly which include 9 thousand globe rupture and 30 thousand blindness due to impacts on the eye. Eye traumas could have occurred as mechanical, radiation, thermal, chemical, etc. among these, the damages related to the airbag impact which is subset of mechanical damages, take a significant percentage. Presenting a model of human eye in car airbag blunt impacts during accident could be effective for receiving helpful information from damage of the internal parts...

Analysis of Contact Geometry Effect on the Slip Amplitude in Fretting Fatigue of a Turbine Blade Root

, M.Sc. Thesis Sharif University of Technology Shirzadi, Saba (Author) ; Adibnazari, Saeed (Supervisor)

Abstract

Turbine blades are exposed to mechanical and thermal stresses due to their operation in critical conditions and get into various damages such as fatigue and wear. These factors reduce the life of the blades and lead to expensive maintenances. As a result, recognizing the type of possible damage helps to increase the life of the blade and to delay the occurrence of failures by taking the necessary actions.The subject of this thesis is to investigate the effect of geometric parameters on the slip amplitude in the root of a turbine blade. In this work, the effect of three parameters of contact area length, contact angle, and coefficient of friction on relative slip amplitude and contact...

Biomechanical simulation of eye-airbag impacts during vehicle accidents

, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 232, Issue 7 , 2018 , Pages 699-707 ; 09544119 (ISSN) Shirzadi, H ; Zohoor, H ; Naserkhaki, S ; Sharif University of Technology

SAGE Publications Ltd 2018

Abstract

Airbags are safety devices in vehicles effectively suppressing passengers’ injuries during accidents. Although there are still many cases of eye injuries reported due to eye-airbag impacts in recent years. Biomechanical approaches are now feasible and can considerably help experts to investigate the issue without ethical concerns. The eye-airbag impact–induced stresses/strains in various components of the eye were found to investigate the risk of injury in different conditions (impact velocity and airbag pressure). Three-dimensional geometry of the eyeball, fat and bony socket as well as the airbag were developed and meshed to develop a finite element model. Nonlinear material properties of...

Optimum mechanism for rehabilitation of fingers

, Article 5th RSI International Conference on Robotics and Mechatronics, IcRoM 2017, 25 October 2017 through 27 October 2017 ; 2018 , Pages 451-456 ; 9781538657034 (ISBN) Yekta, R ; Zohoor, H ; Shirzadi, H ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2018

Abstract

Nowadays, with the advancement of technology, humans are looking for ways to cure various diseases. Meanwhile, musculoskeletal injuries usually have a long treatment period. Therefore, in recent years, Researchers working one exoskeleton with rehabilitation application which conduct physiotherapy tasks. In current study, a portable two degree of freedom hand exoskeleton is designed which its mechanism is a combination of cable and link mechanism, MCP1 1Metacarpophalangeal joint between metacarpal and proximal phalanges joints move by link mechanism, DIP2 2Distal interphalangeal joint between proximal phalanges and middle phalanges and PIP3 3Proximal interphalangeal joint between middle...

Determination of the Equivalent Linear Systems of Nonlinear MDOF Steel Moment Resisting Frames

, M.Sc. Thesis Sharif University of Technology Shirzadi, Tiam (Author) ; Rahimzadeh Rofooei, Fayyaz (Supervisor)

Abstract

The purposeof this study isto findthe propertiesof an equivalent linear Multiple Degrees of Freedom (MDOF) system, or so-called substitute structure, that its response is an approximation ofthe target actualnonlinearMDOF structure’s response (Shodja, 2013). In that regard,thestiffness anddampingmatricesofthe substitutestructure are considered as functions ofthe stiffnessand dampingmatrices ofthe actualnonlinear structure. Inthisway,the substitute structurescan be constructedthroughtrial and errorfor structures with different fundamentalperiods, damping ratios and number of floors.Inthat regard, a number of multi-story steel moment resisting frames are considered. The ductilities of these...

Experimental Study of Water Flow on Migration of DNAPL in Fracture Network: Distribution, Transport and Remediation using Density Modification of Surfactant

, M.Sc. Thesis Sharif University of Technology Shirzadi, Vahid (Author) ; Ghazanfari, Mohammad Hossein (Supervisor)

Abstract

Groundwater is one of the vital sources of drinking water worldwide, yet it faces the risk of contamination from organic and inorganic substances. These pollutants can persist in the environment for extended periods, leading to continuous contamination. One of the key factors in the rapid transport of these contaminants is the presence of fracture networks within porous media. These fractures play a crucial role in facilitating the movement of pollutants to deeper layers of groundwater aquifers. The fracture networks enable contaminants to migrate more rapidly and penetrate various regions, complicating pollution management. Additionally, the natural flow of groundwater acts as a driving...

Integration of miniature heat pipes into a proton exchange membrane fuel cell for cooling applications

, Article Heat Transfer Engineering ; Volume 38, Issue 18 , 2017 , Pages 1595-1605 ; 01457632 (ISSN) Shirzadi, N ; Roshandel, R ; Behshad Shafii, M ; Sharif University of Technology

2017

Abstract

In proton exchange membrane fuel cell (PEMFC) operations, the electrochemical reactions produce a rise in temperature. A fuel cell stack therefore requires an effective cooling system for optimum performance. In this study, miniature heat pipes were applied for cooling in PEMFC. Three alternatives were considered in tests: free convection, forced convection cooling with air, and also water. An analytical model was developed to show the possibility of evoking heat from inside a fuel cell stack with different numbers of miniature heat pipes. An experiment setup was designed and then used for further analysis. The proposed experiment setup consisted of a simulated fuel cell that produced heat...

Comparison of vibration and acoustic responses in a rotary machine balancing process

, Article Applied Acoustics ; Volume 164 , July , 2020 Isavand, J ; Kasaei, A ; Peplow, A ; Afzali, B ; Shirzadi, E ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

Balancing a rotating machine is a vital step towards ensuring it will operate reliably and safely. To achieve this condition monitoring is an important aspect for early faulty detection and it can also result in the improvement of the operational continuity and equipment safety. Imbalance itself, is a common problem in rotating machinery and it can lead to poor or even dangerous vibration levels. And, for example, it is also well known that misalignment can lead to bearing defects. So, in order to overcome these problems many balancing techniques have been developed that are largely based on measured vibration data using accelerometers attached to the faulty device. The three-point method is...

Integration of Miniature Heat Pipes into a PEM Fuel Cell for Cooling Application

, M.Sc. Thesis Sharif University of Technology Shirzadi, Navid (Author) ; Roshandel, Ramin (Supervisor) ; Shafii, Mohammad Behshad (Co-Advisor)

Abstract

Due to the operation of proton exchange membrane fuel cell (PEMFC), temperature will rise because of the electrochemical reactions and control of temperature is one of the most important sections that has influence on the performance of the fuel cell. In this study three alternative for cooling and controlling the temperature situation is proposed and compared. the experimental setup consists of the simulated fuel cell that produce heat just like PEMFC and number of thermosyphon miniature heat pipes for evoke the heat and three types of condenser that makes three different scenario for this cooling setup. Free convection, force convection using Fan and force convection using circulating...

Lumbopelvic Rhythm during Forward and Backward Sagittal Trunk Rotations; in vivo Measurements Using Inertial Sensors

, M.Sc. Thesis Sharif University of Technology Tafazzol, Alireza (Author) ; Arjmand, Navid (Supervisor)

Abstract

Direct in vivo measurements of spinal loads and muscle forces are invasive. Investigators have thus used musculoskeletal biomechanical models that require kinematic data including trunk and pelvis angular movements as their inputs. . Novel devices measure anglular movements using both inertial sensors (such as gyroscopes and accelerometers) and miniature magnetometers. Relative low cost, portability, and accuracy are among specific characteristics of inertial tracking devices. The main objective of the present study was set to measure spinal kinematics including the lumbopelvic rhythm as the ratio of total lumbar rotation over pelvic rotation during trunk sagittal movement which is essential...

Evaluation of 1991 NIOSH Lifting Equation in Controlling the Biomechanical Loads of the Human Spine

, M.Sc. Thesis Sharif University of Technology Lesani, Ali (Author) ; Arjmand, Navid (Supervisor)

Abstract

The 1991 NIOSH Lifting Equation (NLE) is widely used to assess risk of injury to the spine by providing estimates of the recommended weight limit (RWL) in hands. The present study uses two biomechanical models of the spine to verify whether the RWL generates L5-S1 loads within the limits (e.g., 3400 N for compression recommended by NIOSH and 1000 N for shear recommended in some studies).Severallifting activities are simulated here to evaluate the RWL by the NLE and the L5-S1 loads by the models. In lifting activities involving moderate to large forward trunk flexion, the estimated RWL generates L5-S1 spine loads exceeding the recommended limits. The NIOSH vertical multiplier is the likely...

Sagittal Range of Motion of the Thoracic Spine Using Inertial Tracking Device and Effect of Measurement Errors on Model Predictions

, M.Sc. Thesis Sharif University of Technology Hajibozorgi, Mahdieh (Author) ; Arjmand, Navid (Supervisor)

Abstract

Range of motion (ROM) of the thoracic spine has implications in patient discrimination for diagnostic purposes and in biomechanical models for predictions of spinal loads. Few previous studies have reported quite different thoracic ROMs. Total (T1-T12), lower (T5-T12) and upper (T1-T5) thoracic, lumbar (T12-S1), pelvis, and entire trunk (T1) ROMs were measured using an inertial tracking device as asymptomatic subjects flexed forward from their neutral upright position to full forward flexion. Correlations between body height and the ROMs were conducted. Effect of measurement errors of the trunk flexion (T1) on the model-predicted spinal loads was investigated. Mean of peak voluntary total...

A Detailed Finite Element Model of the Lumbar Spine under Muscle Forces

, M.Sc. Thesis Sharif University of Technology Asadi, Hamed (Author) ; Arjmand, Navid (Supervisor)

Abstract

Etiological studies proves the fact that Low Back Pain (LBP) is one of the most expensive and prevalent desease all over the world. This fact illustrates the reqiurment of the special effort in ordet to reducing the pain due to this problem. Finite element modeling of human spine is one the suitable methods to simulate the behavior of human spine in different loading conditions. These conditions could be different daily occupational tasks. There is two general viewpoint toward finite element modeling of human spine. The fisrt method focuses on the detailed geometry and mechanical properties of spine, while the other complexities such as detailed muscle forces are overlooked. The latter...

A Hyrid EMG-optimization Based Model of the Lumbar Spine to Estimate Muscle Forces in Different Tasks

, M.Sc. Thesis Sharif University of Technology Mohammadi, Yousef (Author) ; Arjmand, Navid (Supervisor)

Abstract

Low back pains (LBP) are prevalent and costly. One of the important factors causing LBP is excessive axial compression and shear forces that are applied on the intervertebral discs during different activities. Due to lack of direct in vivo measurement methods for estimating these loads, musculoskeletal biomechanical models have been emerged as indispensable tools under various activities. Different biomechanical models have been suggested to estimate muscle forces and spinal loads base on optimization, EMG and hybrid (EMG assisted optimization, EMGAO) methods. Although there have been a number of studies on the differences between various optimization and EMG-based methods, there has been no...

Effect of Iatrogenic Muscle Injuries on Spine Biomechanics During Posterior Lumbar Surgeries Using a Biomechanical Model for Design of Rehabilitation Exercises

, M.Sc. Thesis Sharif University of Technology Jamshidnezhad, Saman (Author) ; Arjmand, Navid (Supervisor)

Abstract

Posterior lumbar surgery is often associated with extensive injuries to back muscles. In this thesis, the effect of such iatrogenic injuries in some patients was examined. For this purpose, the CSA of back muscles in 6 patients were measured using MR scan. To examine any natural change in CSAs of healthy people or instrument errors, same measurement were carried out on 10 healthy volunteers. In addition, a detailed anatomical model of an intact human spine was developed. With the aim of experimental studies and intact model, the post-operative model of patients was also developed. These two models were used to quantizing the change in activity of back muscles during some symmetric, normal...

3D Measurements of the Thoracic and Lumbar Spine Range of Motions Using Inertial Sensors

, M.Sc. Thesis Sharif University of Technology Narimany, Mohammad (Author) ; Arjmand, Navid (Supervisor)

Abstract

Musculoskeletal abnormalities affect joints and change their range of motion (RoM). Correcting these abnormalities thoroughly depends on the information related to the normal spine movement. Therefore, spine motion analysis can be used as an important tool to distinguish between healthy and patient individuals as well as to determine the intensity of such diseases. Additionally, existing biomechanical models need kinematics data in order to analyze spinal forces. The present study hence aims to measure 3D range of motion of thoracic and lumbar spine using inertial sensors. Their small size, portability, low weight, and relatively low cost make inertial sensors as indispensable tools in...

A Novel Stability-based EMG-assisted Model of the Lumbar Spine to Estimate Trunk Muscle Forces and Spinal Loads in Various Static Activities

, M.Sc. Thesis Sharif University of Technology Samadi, Soheil (Author) ; Arjmand, Navid (Supervisor)

Abstract

The spine like every other mechanical pillar, is exposed to buckling and loss of stability. While existing biomechanical models emphasize the pressure force on the disk as the main cause of injury, there is also a possibility of local buckling phenomenon in vertebral discs. Because of the prevalence and high cost of lower back pain, it is essential to evaluate the forces carried by disks and lumbar muscles during occupational activities more accurately. In this regard, hybrid EMG-assisted optimization (EMGAO) approaches are most common methods for estimation of spinal loads. These models, not only use EMG data to be physiologically creditable, but also satisfy equilibrium requirements at all...

Pull-out Strength Test Simulation and Stability Study of a Patient-Specific Drill Guide Template of Thoracic Pedicle Screw Placement for Patients with Spinal Deformity Using Finite Element Analysis

, M.Sc. Thesis Sharif University of Technology Hosseini, Fahimeh (Author) ; Arjmand, Navid (Supervisor)

Abstract

We have recently designed/fabricated novel bilateral vertebra- and patient-specific drill guides for pedicle screw (PS) placements and tested their accuracy for both nondeformed and deformed thoracic spines. PS placement deviations from their preplanned positions significantly reduced when guide template were used; the success rate improved from ~72% (freehand placements) to 94% (guided placements). In the present study, we aim to use finite element (FE) analyses to evaluate the pull-out strength of these PSs inserted via either the freehand technique or our drill-guide templates. Two 3D-printed T1-T12 thoracic models of a severe scoliosis patient with a 47° thoracic dextro-scoliotic curve...

Biomechanical Evaluation of the Niosh Equation in Stoop Versus Squat Load-Handling Activities Using a Full-Body Musculoskeletal Model

, M.Sc. Thesis Sharif University of Technology Dehghan, Parisa (Author) ; Arjmand, Navid (Supervisor)

Abstract

Objective: To assess adequacy of the National Institute for Occupational Safety and Health (NIOSH) Lifting Equation (NLE) in controlling lumbar spine loads below their recommended action limits during load-handling activities in the stoop and squat using a detailed musculoskeletal model,that is, the AnyBody Modeling System.Background: The NIOSH committee employed simplistic biomechanical models for the calculation of the spine compressive loads with no estimates of the shear loads. In addition, NLE does not include the posture of the knee during manual material handling. It is therefore unknown whether the NLE would adequately control lumbar compression and shear loads below their...

Human Whole-Body Static 3D Posture Prediction in One- and Two-Handed Lifting Tasks from Different Load Positions using Machine Learning

, M.Sc. Thesis Sharif University of Technology Mohseni, Mahdi (Author) ; Arjmand, Navid (Supervisor)

Abstract

Biomechanical models require body posture to evaluate the risk of musculoskeletal injuries during daily/occupational activities like manual material handling (MMH). The procedure to measure body posture via motion-analysis techniques is complex, time-consuming, and limited to equipped laboratories. This study aims to develop an easy-to-use yet accurate model that predict human whole-body static posture (3D body coordinates and anatomical joint angles) during different MMH activities. Twenty healthy male right-handed individuals with body mass index between 18 and 26 performed 204 symmetric and asymmetric MMH activities. Each person reached (i.e., without any load in hands) the destinations...