Search for: tendons
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    The development of a Smart Shoulder-wheel for Analysis of Shoulder Tendonitis Injuries

    , M.Sc. Thesis Sharif University of Technology Hashemi, Naser (Author) ; Behzadipour, Saeed (Supervisor)
    Nowadays the process of making smart rehabilitations' equipment is at the centre of physicists' attention, so this affair is a matter of research in the medical engineering.Amongst of the advantages of this method there are: increasing the efficiency, recording patients' information, no need for continuous physiotherapists and therapists' presence in all the process of medical treatment, and saving time and money. In addition, due to removing traditional methods of rehabilitation, the precision and control ability of medical treatment is considerably increased, reducing the unexpected injuries during the exercise. The shoulder wheel is one of the useful devise in clinics physiotherapy... 

    Investigation of TLP behavior under tendon damage

    , Article Ocean Engineering ; Volume 156 , 15 May , 2018 , Pages 580-595 ; 00298018 (ISSN) Tabeshpour, M.R ; Ahmadi, A ; Malayjerdi, E ; Sharif University of Technology
    Elsevier Ltd  2018
    Exact calculation of stiffness matrix of TLP is important for investigation of its behavior in intact and tendon damage conditions and it is necessary to design a reliable TLP. A serious attention has been concentrated on this problem in API-RP-2T and various aspects of that such as dynamic and static behavior of TLP, tendon tensions after one tether failure. Also it has introduced safety factors in different loads and healthy conditions. This paper deals with effect of damage tendon condition of TLP on behavior and tensions of tendons in wave frequency range. Equilibrium of TLP is studied and stiffness matrix of TLP is derived in tendon damage condition. Wave loads and hydrodynamic... 

    Vibration Analysis of Tension Leg Platform’s Tendon

    , M.Sc. Thesis Sharif University of Technology Hedayatpour, Reza (Author) ; Tabeshpour, Mohammad Reza (Supervisor) ; Mehdigholi, Hamid (Co-Advisor)
    Tension leg platforms (TLPs) are well-known structures for oil exploitation in deep water. Tethers are one of the most important component of these structures. Nonlinear response of TLP tethers under the combined action of wave and current was investigated in the present issue. Both the quadratic damping due to fluid resistance and parametric excitation due to top tension variations are included in the mathematical model. Only the vortex-induced transverse oscillations under lock on conditions were examined. A fourth order runge-kutta method was used to solve the equations of motion of tendons. The effects of surge motion coupling on the heave motion, the effects of tendon's oscillation on... 

    Design and Analysis of a Force-Isotropic Underactuated Humanoid Hand

    , M.Sc. Thesis Sharif University of Technology Alizadeh, Milad (Author) ; Zohoor, Hassan (Supervisor)
    Robots have been widely used for various applications, especially during the last decades. Robots are made of several parts, in which, "Hand" is one of the most important of those. Hands are designed according to their applications and are not necessarily like human ones. Development of humanoid robots, however, brings a special place to human-like hands. In this research, a force-isotropic underactuated finger with two phalanxes and one actuator is designed, considering design limitations and through static analysis. Tendon, cam and mechanical lock (ratchet gear) are among the main components which have been considered in the finger design. Then, a model was fabricated and tested in order... 

    Numerical Evaluation for Optimal Design of Number and Positions of Controllers In 2d Frames under Earthquake and Wind Loadings Using Different Active Control Algorithms

    , M.Sc. Thesis Sharif University of Technology Mehdipour Picha, Zabihollah (Author) ; Bakhshi, Amin (Supervisor)
    Structures which are designed in accordance with previously used design codes are usually weak to sustain dynamic loading and therefore they shall be rehabilitated. One approach for rehabilitation is to use active control. In this study, active tendon is used as a structural device control. Various arrangements of controllers can be used to limit the response of the structure but it is desired to find an arrangement at which the cost of the placement will be minimized. The aim of this thesis is to find the best placement of active tendons on a frame such that the placement satisfies two general restrictions; namely structural response and control forces. Genetic algorithm is applied to the... 

    Optimization, Fabrication and Utilization of a New Tendon Actuated Manipulator with Lockable Joints

    , M.Sc. Thesis Sharif University of Technology Shafaei, Mohsen (Author) ; Alasty, Aria (Supervisor) ; Salarieh, Hassan (Supervisor)
    Serpentine manipulators are a kind of hybrid manipulators that have a large number of joints and degrees of freedom. Due to their high flexibility, they have a great potential to work in constrained environment that filled with obstacles. One of the main problems of this type of manipulators is high weight and controlling difficulties. Many researches have been done to achieve lighter weight and simplify control methods of hyper-redundant manipulator. One way is putting the actuators in the base of the manipulator and transferring the actuator forces by cable. In this way, one cable and one actuator per controllable DOF is needed. Therefore, the weight and cost will increase dramatically... 

    The Effectiveness of Vibration Absorber on the Behavior of TLP Floating Offshore Wind Turbine in the Situation of Tendon Failure

    , M.Sc. Thesis Sharif University of Technology Bahaelou Horeh, Erfan (Author) ;
    For many years, humans have been able to use wind energy to meet some of their needs. By improving science and the discovery of electricity as the mother of energy that is very easy to use, mankind thought of converting wind energy into electricity, so wind turbines were invented. Despite the wide spread of onshore wind turbines, their visual, acoustic and environmental negative effects still cause dissatisfaction among the residents of the areas where these turbines are installed. Also, the high wind speed in the seas compared to the land ares has caused the interest to use offshore wind turbines to increase in the past years. For this reason, an attempt has been made in this thesis to... 

    Optimal control of nonlinear frames by Newmark and distributed genetic algorithms

    , Article Structural Design of Tall and Special Buildings ; Volume 21, Issue 2 , 2012 , Pages 77-95 ; 15417794 (ISSN) Joghataie, A ; Mohebbi, M ; Sharif University of Technology
    Active control of multi-storey frame structures with nonlinear hysteretic response has been studied in this paper. A new nonlinear optimal control algorithm based on nonlinear Newmark integration method and distributed genetic algorithm (DGA) has been developed. The objective has been to reduce the response to below any desired level. In this study, DGA has been used to determine the weights in the control law corresponding to displacement, velocity and acceleration. The capabilities of the method has been assessed through simulation where an eight-storey frame with bilinear hysteretic behaviour has been subjected to a white noise ground acceleration and controlled by the controllers... 

    Strengthening of metallic beams with different types of pre-stressed un-bonded retrofit systems

    , Article Composite Structures ; Volume 159 , 2017 , Pages 81-95 ; 02638223 (ISSN) Kianmofrad, F ; Ghafoori, E ; Elyasi, M. M ; Motavalli, M ; Rahimian, M ; Sharif University of Technology
    Elsevier Ltd  2017
    Unlike bonded retrofit systems, un-bonded systems do not need any surface preparation prior to bond application, which reduces the overall time and cost of a retrofit plan. Because the carbon fiber reinforced polymer (CFRP) plate in the un-bonded (tendon) systems is not bonded to a metallic substrate, different variants of the retrofit systems can be developed to ease application in the field. This paper presents four different variants of the prestressed un-bonded retrofit (PUR) systems: trapezoidal PUR (TPUR), triangular PUR (TriPUR), Flat PUR (FPUR), and Contact PUR (CPUR) systems. Analytical solutions based on the flexibility approach are developed to predict the behavior of the metallic... 

    Can the body slope of interference screw affect initial stability of reconstructed anterior cruciate ligament?: An in-vitro investigation

    , Article BMC Musculoskeletal Disorders ; Volume 22, Issue 1 , 2021 ; 14712474 (ISSN) Daneshvarhashjin, N ; Chizari, M ; Mortazavi, J ; Rouhi, G ; Sharif University of Technology
    BioMed Central Ltd  2021
    Background: Superior biomechanical performance of tapered interference screws, compared with non-tapered screws, with reference to the anterior cruciate ligament (ACL) reconstruction process, has been reported in the literature. However, the effect of tapered interference screw’s body slope on the initial stability of ACL is poorly understood. Thus, the main goal of this study was to investigate the effect of the interference screw’s body slope on the initial stability of the reconstructed ACL. Methods: Based on the best screw-bone tunnel diameter ratios in non-tapered screws, two different tapered interference screws were designed and fabricated. The diameters of both screws were equal to... 

    Investigation and Analysis of Response Behavior of Tension Leg Platform under Impulse and Limit Loads (In order to Investigate the Phenomenon of Tendon Disconnection)

    , M.Sc. Thesis Sharif University of Technology Belvasi, Navid (Author) ; Tabeshpour, Mohammad Reza (Supervisor)
    Given the increasing development of exploitation of deepwater oil and gas resources, access to realistic solutions for analyzing and designing offshore platforms is a major factor in facilitating the exploitation of oil and gas resources in these areas. There is a huge amount of oil reservoirs in deep water beds, and Tension leg platform (TLP), as a compliant structure, are suitable for oil extraction in deep water.The advantage of using these platforms is the ability to rotate and move at a rate of rotational and transient freedom. Surge motion The TLP is a 120-second long period; In high-amplitude and low period waves, the platform faces a tendon rupture due to high waves forces and bad... 

    Exprimental and Numerical Analysis of Tlp Floating Offshore Wind Turbine with one Tendon Failure

    , M.Sc. Thesis Sharif University of Technology Helalat, Zeynab (Author) ; Tabeshpour, Mohammad Reza (Supervisor)
    Offshore wind energy is widely recognized as a renewable energy source that has the potential as a global energy source. Although the use of coastal wind turbines has been successful, it has been challenged in terms of visual, acoustic and environmental impacts. In addition, in terms of technology, it is difficult to achieve high levels of energy from coastal wind resources due to low annual average speed; Therefore, the wind energy industry is trying to make more use of the deep-water wind resources. However, before developing these types of deep-water turbines, economic challenges and technical problems must be resolved. Mooring failure is one of the major issues in the design of offshore... 

    Stability and Dynamic Response of Tension Leg Platform in Damaged Condition (Tendon Removed)

    , M.Sc. Thesis Sharif University of Technology Mahmoodi, Mohammad Reza (Author) ; Tabeshpour, Mohammad Reza (Supervisor)
    The tension leg platform is one of the compliant structures which are generally utilized for deep water oil explorations. With respect to the horizontal degrees of freedom, it behaves like a floating structure moored by vertical tethers which are pretension due to the excess buoyancy of the platform, whereas with respect to vertical degrees of freedom it is stiff and resembles a fixed structure and is not allowed to float freely. A sudden disconnection of a tendon causes a change of stiffness and unbalance of forces and moments of the total system. The objective of this study is experimental and numerical investigation on behavior of ISSC TLP. Experiments were performed in the National... 

    Path Planning and Hybrid Control of a Tendon Actuated Redundant Manipulator with Lockable Joints

    , M.Sc. Thesis Sharif University of Technology Taherifar, Ali (Author) ; Alasty , Aria (Supervisor) ; Salarieh, Hassan (Supervisor)
    Snake-arms are hyper redundant manipulators that have high degree of freedom. Due to their high flexibility they have a great potential to work in the fully restrained, complex and hazardous environments such as Nuclear reactors and space stations. They can also be used for surgery, exploration and rescue. In this thesis the path planning and kinematic control of a special type of snake arm are investigated. In this manipulator, the extra cables are replaced by a locking system to reduce weight of the structure and the number of actuators. Therefore, by releasing and locking the joints in arbitrary sequence and by stretching the cables, the configuration of manipulator will change. This... 

    Design, Simulation and Control of a New Tendon Actuated Manipulator With Lockable Joints

    , M.Sc. Thesis Sharif University of Technology Honarvar, Mohammad (Author) ; Alasty, Aria (Supervisor) ; Salarieh, Hasan (Supervisor)
    Hyper-redundant manipulators have large number Degrees of Freedom. Because of their redundancy, such manipulators have the advantage of obstacle avoidance, overcoming singularities and intrusion into highly constrained environments. The most challenging task in designing hyper-redundant manipulators is the synthesis of actuating mechanisms with appropriate kinematics and effective power supply. Most of previous techniques in implementing hyper-redundant robots have the disadvantages of: -Using large number of actuators, -Heavy weight due to large number of actuators, -Complexity of the control system due to need of synchronizing subsets of motors. In this thesis a novel hyper redundant... 

    Fatigue Reliability of Tension-Leg Platform Tendon under Random Wave Load

    , M.Sc. Thesis Sharif University of Technology Nazari, Negin (Author) ; Tabeshpour, Mohammad Reza (Supervisor)
    The primary objective of this research is probabilistic quantification of the fatigue life of tension-leg platforms (TLP) using reliability methods. The need for such methods stems from the significant uncertainty in the loads exerted on offshore structures. The scope of this paper is limited to the study of fatigue in TLP tendons. For this purpose, nonlinear force time history response of the TLP tendon under random wave loads is computed and the damage due to fatigue is estimated in accordance with the Palmgren-Miners rule. Assuming a Rayleigh distribution for stress variation and eight different sea states, the ultimate fatigue damage is computed by accumulating the damage over all... 

    Do the soft tissues located outside tibiofemoral joint have a role in bearing the compressive loads of the joint? An in-vitro study on sheep stifle joints

    , Article Gazzetta Medica Italiana Archivio per le Scienze Mediche ; Volume 172, Issue 7-8 , 2013 , Pages 595-601 ; 03933660 (ISSN) Hakkak, F ; Rostami, M ; Parnianpour, M ; Jabalameli, M ; Sharif University of Technology
    Aim. The compressive loads on the tibiofemoral joint are normally assumed to be borne solely via contact and pressing of the cartilage surfaces of tibia and femur. However, recent findings suggest that non-contact load-bearing mechanisms are active in the joint as well. In this context, a non-contact load-bearing mechanism involving soft tissue connections outside the tibiofemoral joint has been hypothesized as well. This paper addresses the validity of this hypothesis and the possible involvement of several soft tissue connections outside the joint. Methods. Sheep stifle (knee) joints were studied in vitro. The specimens were loaded in fixed displacement. Various soft tissues outside the... 

    Comparison of mechanical properties in interference screw fixation technique and organic anterior cruciate ligament reconstruction method: a biomechanical study

    , Article BMC Musculoskeletal Disorders ; Volume 22, Issue 1 , 2021 ; 14712474 (ISSN) Borjali, A ; Nourani, A ; Moeinnia, H ; Mohseni, M ; Korani, H ; Ghias, N ; Chizari, M ; Sharif University of Technology
    BioMed Central Ltd  2021
    Background: Bone and Site Hold Tendon Inside (BASHTI) technique is an organic implant-less technique for anterior cruciate ligament (ACL) reconstruction with some clinical advantages, such as speeding up the healing process, over implantable techniques. The study aims to compare the mechanical properties of BASHTI technique with the conventional interference screw technique. Methods: To investigate the mechanical properties, 20 in-vitro experimental tests were conducted. Synthetic dummy bone, along with fresh digital bovine tendons, as a graft, were used for experiments. Three loading steps were applied to all specimens, including a preconditioning, a main cyclic, and a pull-out loading.... 

    Micromechanical modeling of rate-dependent behavior of Connective tissues

    , Article Journal of Theoretical Biology ; Volume 416 , 2017 , Pages 119-128 ; 00225193 (ISSN) Fallah, A ; Ahmadian, M. T ; Firozbakhsh, K ; Aghdam, M. M ; Sharif University of Technology
    Academic Press  2017
    In this paper, a constitutive and micromechanical model for prediction of rate-dependent behavior of connective tissues (CTs) is presented. Connective tissues are considered as nonlinear viscoelastic material. The rate-dependent behavior of CTs is incorporated into model using the well-known quasi-linear viscoelasticity (QLV) theory. A planar wavy representative volume element (RVE) is considered based on the tissue microstructure histological evidences. The presented model parameters are identified based on the available experiments in the literature. The presented constitutive model introduced to ABAQUS by means of UMAT subroutine. Results show that, monotonic uniaxial test predictions of... 

    Kinematic control of a new hyper-redundant manipulator with lockable joints

    , Article Scientia Iranica ; Volume 20, Issue 6 , 2013 , Pages 1742-1752 ; 10263098 (ISSN) Taherifar, A ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    Sharif University of Technology  2013
    Kinematic control of a special hyper-redundant manipulator with lockable joints is studied. In this manipulator, the extra cables are replaced by a locking system to reduce the weight of the structure and the number of actuators. This manipulator has discrete and continuous variables due to its locking system. Therefore, a hybrid approach has been adopted in control. At first the forward kinematics and velocity kinematics of this manipulator are derived, and then a novel closed-loop control algorithm is presented. This algorithm consists of decision making, an inner loop controller, and kinematic calculation blocks. The decision making block is the logical part of the control scheme in which...