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    A Numerical Study of Bearing Capacity Factors for Shallow Foundations

    , M.Sc. Thesis Sharif University of Technology Sharifian, Hadi (Author) ; Ahmadi, Mohammad Mehdi (Supervisor)
    Abstract
    Determination of ultimate bearing capacity of shallow foundations has been discussed since long time ago in many books and papers. Although this is not generally a new problem, there are still some problems which may be interesting to be investigated in detail using suitable computer programs and by application of appropriate soil models. Comprehensive surveys on bearing capacity coefficients of different foundations have been done by utilizing FLAC software. The failure of soil is governed by the Elasto-Plastic Mohr-coulomb criterion. New graphs and equations have been developed for determining the coefficients. The equations achieved in this study by numerical methods, have been compared... 

    Dynamic Simulation of the Biped Normal and Amputee Human Gait

    , M.Sc. Thesis Sharif University of Technology Akbari Shandiz, Mohsen (Author) ; Farahmand, Farzam (Supervisor) ; Zohour, Hassan (Supervisor)
    Abstract
    One of the best methods of gait analysis is to use analytical models. In this project, first, the normal human gait was simulated using a two-dimensional biped model with 7 segments, i.e., a HAT segment representing head, arms and trunk, and 6 segments representing thighs, shanks and feet of the two legs. The foot-ground contact was simulated using a five-point penetration contact model. The elastic impact and friction effects are considered in the ground reaction force modeling. Optimization of the normal human walking model provided constant coefficients for simple PD controllers’ (driving torque) equations that could reasonably reproduce the normal kinematical pattern. Then, in the second... 

    Dynamic Simulation of Running Human Normal and with Below-Knee Prosthesis

    , M.Sc. Thesis Sharif University of Technology Ebrahimi Mamaghani, Ali (Author) ; Firoozbakhsh, Keykhosro (Supervisor) ; Zohoor, Hassan (Supervisor)
    Abstract
    Researches in the field of human gait have a lot of applications in medicine, ergonomics, sport science and technology. Lower limb prostheses design is one of the fields in which human gait is important. One of the best methods of gait analysis is to use analytical models. In this project, first, the normal human was simulated using a two-dimensional biped model with 7 segments, i.e., a HAT segment representing head, arms and trunk, and 6 segments representing thighs, shanks and feet of the two legs. In this model the foot-ground contact was is estimated using Taylor series after running experiment and it’s analysis which is expendable to people with different ages and different weight and... 

    Investigation of Dynamic Response of Shallow Foundations on Sandy Soil to Horizontal Harmonic Loading by Physical Model Tests

    , M.Sc. Thesis Sharif University of Technology Ghassemi, Ramin (Author) ; Jafarzadeh, Fardin (Supervisor)
    Abstract
    The most important step in current dynamic analysis of machine foundations is determining dynamic impedance functions. Impedance functions are defined as ratios of applied force or moment to induced displacement or rotation angle of foundation. In this research, horizontal dynamic response of foundation on homogeneous halfspace was investigated using physical modeling. Soil medium was built in a 1mx1mx0.8m steel box whose interior walls were covered by 0.1m of sawdust (a material with high damping). In order to prevent possible reflection of waves, this cover was extended to the box bottom with 0.2 m thickness. Sand raining method was used to build soil medium. In this method, with... 

    Numerical Study of Dynamic Response of Shallow Foundations to Vertical Loads Induced by Machines

    , M.Sc. Thesis Sharif University of Technology Pourdeilami, Abbas (Author) ; Ahmadi, Mohammad Mehdi (Supervisor)
    Abstract
    The main purpose of designing machine foundation is to limit its motion to such an amount that not to prevent the perfect workability of machine, not to let the foundation strains exceed the elastic limit and also not to disturb the persons working around the machine. The key note in successfull design of machine foundation, is to precisely analyse the response of foundation to dynamic loads induced by machine operations.The numerical study of shallow foundations response to vertical harmonic loads induced by machinaries have been discussed in this investigation.To aim this purpose, FLACD3D has been utilized in order to 3 dimensionally analyse a continuum medium comprising soil-foundation or... 

    Investigation of Dynamic Response of Foundations on Sandy Soils to Two-Way Horizontal Harmonic Loading by Physical Model Tests

    , M.Sc. Thesis Sharif University of Technology Maleki, Jafar (Author) ; Jafarzadeh, Fardin (Supervisor)
    Abstract
    Increasing requirements of industries and research institutes to analytical results of interaction soil-foundation related systems, reveals the importance of the dynamic impedance functions than ever before. The dynamic impedance function relations are presented for massless rigid foundations which is possible to obtain dynamic response of foundations for different frequencies and masses accordingly. In this study, the dynamic impedance functions were investigated using physical modeling tests on sandy soil with finite thickness soil stratum over bedrock. The tests were carried out inside a steel container of dimensions 1*1*0.8m in length, width and height respectively which was filled into... 

    Numerical Study of Parameters Affecting the Bearing Capacity of Shallow Foundations

    , M.Sc. Thesis Sharif University of Technology Yousefi, Mohammad Reza (Author) ; Ahmadi, Mohamad Mehdi (Supervisor)
    Abstract
    Thread the bearing capacity of soil beneath the foundations of the main topics in Engineering is considered that main reason it is the more contact structures. if all the factors that are likely to impact on bearing capacity is more useful to consider more accurate results are obtained. This thesis has tried using FLAC software is a comprehensive review on the soil bearing capacity of foundations under certain conditions of Geotechnical and foundation strip, can be done .The modeling of soil layers and soil bearing capacity based on changes in properties (clay and sandy soils) and changes in depth are examined. The changes in the deep layer of soil and properties of soil, bearing capacity is... 

    Assessment of Effectivness of Compaction Improvement for Liquefaction Mitigation of Saturated Sand Deposits Based on Performance Levels of Shallow Foundations

    , Ph.D. Dissertation Sharif University of Technology Shahir, Hadi (Author) ; Pak, Ali (Supervisor) ; Ghannad, Mohammad Ali (Supervisor)
    Abstract
    Settlement and tilt of structures due to liquefaction of subsoil layers is a major cause of damage during earthquake. One of the main approaches to reduce terrible effects of liquefaction on shallow foundations is ground improvement. Among the variety of ground improvement methods, the densification-based methods have been more paid attention for liquefaction mitigation. For liquefaction hazard mitigation using densification methods, three basic values should be determined i.e. depth, lateral extent, and degree of improvement (percent increase in Dr). In the current design practice, the need for ground improvement is usually decided based on the semi-empirical methods for assessment of... 

    Investigation of Dynamic Response of Shallow Foundations on Layered Soils to Horizontal Harmonic Loading by Physical Model Tests

    , M.Sc. Thesis Sharif University of Technology Ashoori, Taha (Author) ; Jafarzadeh, Fardin (Supervisor)
    Abstract
    Increasing requirements of industries and research institutes to analytical results of interaction soil-foundation related systems, reveals the importance of the dynamic impedance functions than ever before. The dynamic impedance function relations are presented for massless rigid foundations which is possible to obtain dynamic response of foundations for different frequencies and masses accordingly. In this study, the dynamic impedance functions were investigated using physical modeling tests on sandy soil with finite thickness soil stratum over bedrock. The tests were carried out inside a steel container of dimensions 110.8m in length, width and height respectively which was filled into... 

    Design and Fabrication of a Wearable Plantar Pressure Measuring System Using Force Sensing Resistor (FSR)

    , M.Sc. Thesis Sharif University of Technology Shams, Mir Milad (Author) ; Farahmand, Farzam (Supervisor) ; Narimani, Roya (Supervisor)
    Abstract
    The recent project can be considered as a subset of Telerehabilitation, in the field of Telerehabilitation can be defined as the need for long-term data recording in order to determine each individual's movement pattern and compare it to the individual's best model or best practice. With this perspective, it can be said that the recent project, in more detail, remotely targets the use of foot plantar pressure to determine locomotor parameters. With this description, the FSR or force sensitive resistor sensor was selected for a number of reasons, including low cost, low weight and low thickness, and the data acquisition circuit was used to convert the sensors' analog signal to digital output,... 

    Design, construction, and evaluation of “sensor lock”: an electromechanical stance control knee joint

    , Article Disability and Rehabilitation: Assistive Technology ; Volume 13, Issue 3 , 2018 , Pages 226-233 ; 17483107 (ISSN) Arazpour, M ; Ahmadi Bani, M ; Baniasad, M ; Samadian, M ; Golchin, N ; Sharif University of Technology
    Taylor and Francis Ltd  2018
    Abstract
    Background and aim: Most currently-available stance control knee ankle foot orthoses (SCKAFOs) still need full knee extension to lock the knee joint, and they are still noisy, bulky, and heavy. Therefore, the aim of this study was to design, construct, and evaluate an original electromechanical SCKAFO knee joint that could feasibly solve these problems, and thus address the problems of current stance control knee joints with regards to their structure, function, cosmesis, and cost. Method: Ten able-bodied (AB) participants and two (knee ankle foot orthosis) KAFO users were recruited to participate in the study. A custom SCKAFO with the same set of components was constructed for each... 

    Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury

    , Article Disability and Rehabilitation: Assistive Technology ; March , 2018 , Pages 1-5 ; 17483107 (ISSN) Maleki, M ; Badri, S ; Shayestehepour, H ; Arazpour, M ; Farahmand, F ; Mousavi, M. E ; Abdolahi, E ; Farkhondeh, H ; Head, J. S ; Golchin, N ; Mardani, M. A ; Sharif University of Technology
    Taylor and Francis Ltd  2018
    Abstract
    Background: The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. Method: A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were... 

    Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury

    , Article Disability and Rehabilitation: Assistive Technology ; Volume 14, Issue 4 , 2019 , Pages 333-337 ; 17483107 (ISSN) Maleki, M ; Badri, S ; Shayestehepour, H ; Arazpour, M ; Farahmand, F ; Mousavi, M. E ; Abdolahi, E ; Farkhondeh, H ; Head, J. S ; Golchin, N ; Mardani, M. A ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Abstract
    Background: The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. Method: A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were... 

    Rigid vs compliant contact: an experimental study on biped walking

    , Article Multibody System Dynamics ; Volume 45, Issue 4 , 2019 , Pages 379-401 ; 13845640 (ISSN) Khadiv, M ; Moosavian, S. A. A ; Yousefi-Koma, A ; Sadedel, M ; Ehsani Seresht, A ; Mansouri, S ; Sharif University of Technology
    Springer Netherlands  2019
    Abstract
    Contact modeling plays a central role in motion planning, simulation and control of legged robots, as legged locomotion is realized through contact. The two prevailing approaches to model the contact consider rigid and compliant premise at interaction ports. Contrary to the dynamics model of legged systems with rigid contact (without impact) which is straightforward to develop, there is no consensus among researchers to employ a standard compliant contact model. Our main goal in this paper is to study the dynamics model structure of bipedal walking systems with rigid contact and a novel compliant contact model, and to present experimental validation of both models. For the model with rigid... 

    Effect of vibration on postural control and gait of elderly subjects: a systematic review

    , Article Aging Clinical and Experimental Research ; Volume 30, Issue 7 , 2018 , Pages 713-726 ; 15940667 (ISSN) Aboutorabi, A ; Arazpour, M ; Bahramizadeh, M ; Farahmand, F ; Fadayevatan, R ; Sharif University of Technology
    Springer International Publishing  2018
    Abstract
    Background and aim: Gait and balance disorders are common in the elderly populations, and their prevalence increases with age. This systematic review was performed to summarize the current evidence for subthreshold vibration interventions on postural control and gait in elderly. Method: A review of intervention studies including the following words in the title/abstract: insole, foot and ankle appliances, vibration, noise and elderly related to balance and gait. Databases searched included PubMed, ISI Web of Knowledge, Ovid, Scopus, and Google Scholar. Fifteen articles were selected for final evaluation. The procedure was followed using the preferred reporting items for systematic reviews... 

    Comparing Two orthoses for managing medial knee osteoarthritis: lateral wedge with subtalar strap while barefoot versus lateral wedged insole fitted within sandal

    , Article Indian Journal of Orthopaedics ; Volume 56, Issue 2 , 2022 , Pages 319-326 ; 00195413 (ISSN) Falahatgar, M ; Jalali, M ; Babaee, T ; Safaeepour, Z ; Torkaman, A ; Baniasad, M ; Sharif University of Technology
    Springer  2022
    Abstract
    Background: Using foot orthoses for managing medial knee osteoarthritis (MKOA) is common, although its effectiveness is in debate. Most orthoses are placed inside the shoe as a lateral wedged insole. Thus, most studies in this area have focused on the effect of insoles used with shoes. This study compared the effects of a lateral wedge with subtalar strap (combined insole) used while barefoot and lateral wedged insole fitted within sandal on pain, function and external knee adduction moment (EKAM) in patients with MKOA to consider which orthotic treatment is better. Methods: In this quasi-experimental pretest–posttest study, 29 participants with medial knee osteoarthritis were divided into... 

    The gait and energy efficiency of stance control knee-ankle-foot orthoses: A literature review

    , Article Prosthetics and Orthotics International ; Volume 40, Issue 2 , 2016 , Pages 202-214 ; 03093646 (ISSN) Rafiaei, M ; Bahramizadeh, M ; Arazpour, M ; Samadian, M ; Hutchins, S. W ; Farahmand, F ; Mardani, M. A ; Sharif University of Technology
    SAGE Publications Inc  2016
    Abstract
    Background: The use of knee-ankle-foot orthoses with drop locked knee joints produces some limitations for walking in subjects with quadriceps muscle weakness. The development of stance control orthoses can potentially improve their functionality. Objectives: The aim of this review was to compare the evidence of the effect of stance control orthoses to knee-ankle-foot orthoses with drop locked knee joints in improving kinematic variables and energy efficiency of walking by subjects with quadriceps muscle weakness caused by different pathologies. Study design: Literature review. Methods: Based on selected keywords and their composition, a search was performed in Google Scholar, PubMed,... 

    A systematic review of the effect of foot orthoses and shoe characteristics on balance in healthy older subjects

    , Article Prosthetics and Orthotics International ; Volume 40, Issue 2 , 2016 , Pages 170-181 ; 03093646 (ISSN) Aboutorabi, A ; Bahramizadeh, M ; Arazpour, M ; Fadayevatan, R ; Farahmand, F ; Curran, S ; Hutchins, S. W ; Sharif University of Technology
    SAGE Publications Inc  2016
    Abstract
    Background: Foot orthoses are used to optimize lower extremity function and can improve postural stability by enhancing the afferent somatosensory feedback available to the central nervous system. Objective: The aim of this review was to evaluate the effect of foot orthoses on balance control in older subjects. Study design: Systematic review. Methods: The search strategy was based on the Population Intervention Comparison Outcome method. A search was performed in PubMed, Science Direct, Google Scholar, and ISI Web of Knowledge databases by using selected keywords. A total of 22 articles were selected for final evaluation. Results: The results demonstrated that older people should be advised... 

    A new 3D, microfluidic-oriented, multi-functional, and highly stretchable soft wearable sensor

    , Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) Annabestani, M ; Esmaeili Dokht, P ; Olyanasab, A ; Orouji, N ; Alipour, Z ; Sayad, M. H ; Rajabi, K ; Mazzolai, B ; Fardmanesh, M ; Sharif University of Technology
    Nature Research  2022
    Abstract
    Increasing demand for wearable devices has resulted in the development of soft sensors; however, an excellent soft sensor for measuring stretch, twist, and pressure simultaneously has not been proposed yet. This paper presents a novel, fully 3D, microfluidic-oriented, gel-based, and highly stretchable resistive soft sensor. The proposed sensor is multi-functional and could be used to measure stretch, twist, and pressure, which is the potential of using a fully 3D structure in the sensor. Unlike previous methods, in which almost all of them used EGaIn as the conductive material, in this case, we used a low-cost, safe (biocompatible), and ubiquitous conductive gel instead. To show the... 

    Dynamics of a running below-knee prosthesis compared to those of a normal subject

    , Article Journal of Solid Mechanics ; Volume 5, Issue 2 , 2013 , Pages 152-160 ; 20083505 (ISSN) Mamaghani, A. E ; Zohoor, H ; Firoozbakhsh, K ; Hosseini, R ; Sharif University of Technology
    Islamic Azad University  2013
    Abstract
    The normal human running has been simulated by two-dimensional biped model with 7 segments. Series of normal running experiments were performed and data of ground reaction forces measured by force plate was analyzed and was fitted to some Fourier series. The model is capable to simulate running for different ages and weights at different running speeds. A proportional derivative control algorithm was employed to grant stabilization during each running step. For calculation of control algorithm coefficients, an optimization method was used which minimized cinematic differences between normal running model and that of the experimentally obtained from running cycle data. This yielded the...