In this study, a three-dimensional CAD system for biomechanical simulations was developed. Some human interfaces and the graphical routines were utilized effectively to emulate the medical operations and to enhance intuitive ones. A pair of the knee joint finite element model was used to evaluate the performance of this system. The replacement of the artifial joint and the control of the insertion direction of the prothesis were possible easily compared with the traditional CAD systems.

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A power assist mechanism for one hand drive wheelchair developed in our research group is improved. In this paper, basic structure of new assist mechanism is represented. New assist mechanism is able to assist left and right wheels individually. This mechanism is available for brake or stopper on slope and so on. These functions are necessary for one hand use wheelchairs.

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Leg pedalling wheelchairs have been developed for the purpose of retaining muscle forces and preventing bones from degenerating due to used legs of disabled persons. Not enough to pedal the wheelchair by their own muscles, it will be necessary to assist muscle forces. Electrical stimulations on legs to assist muscle forces were evaluated by using the wheelchair. At the staring high-voltage stimulation on quadreceps and hamstrings only could not move the chair on a plane surface, and a motor was used to assist the weakened muscles with composing control-system. Using a motor assist for weakened muscles, starting and driving slopes of wheelchair can be realized easily with low-voltage stimulation.

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For both maintaining and improving walking ability of the elderly or the injured, walking with an aid is most effective. The walking aids in today's market are primarily for helping people on a flat surface such as on hospital corridors. However, to widen the range of terrain on which the aids can be used to include rough pavements or bumps is necessary to assure the users' daily self-sufficient life. This requirement brings some challenging tasks to structural designers. The aid structure should be stiff enough to give the user sure support feeling. At the same time, it should protect the user's hands from unnecessary vibration caused by bumps. Improving stability without major weight increase is another challenge. To solve these problems, both analytical and experimental vibration mode analyses were conducted on a typical conventional walking aid. Combined with operating condition vibration monitoring and multi-body-dynamics simulations of the aid's motion on a bump, the structural weak points were found.

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In this paper, a lifting up device for the walking support machine to prevent fair is discussed. We propose a new control algorithm using virtual compliance control. When a patient use this machine normally in his rehabilitation, we use very small compliance not to disturb his rehabilitation. Just after the machine detect the fall, we change the compliance more stiff to support the patient without shock. Experimental study is carried out and it can be seen that the proposed control method is very useful.

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Bediest and spaceflight are associated with profound losses of muscle bulk and strength which hinder patient's or astronaut's health and reintegration into daily life. First, we assessed the potential of hybrid electrical stimulation-volitional contraction exercise, program to increase proximal lower extremity strength, muscle bulk, and bone mineral density (BMD). Second, we assessed the utility of unilateral lower limb suspension (ULLS). More specifically, this study made an initial evaluation of ability of hybrid exercise program to preserve knee extensor and flexor maximum volitional contraction (MVC), cross-sectional area (CSA), and BMD in 4 healthy men average ages of 22.5, and utility of ULLS in producing decrements in these parameters similar to those that occur in weightless environment in single 18 year-old male. Results: CSA of knee extensors and flexors increased and femoral BMD and MVC. ULLS resulted in dramatic losses of strength, CSA, and BMD.

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Recently, hip pads to prevent the femur fracture by falling have been developed for aged persons. It is necessary for hip pads that the material and the structure select and design to realize the higher performance of impact absorption. In this work, an experimental system was made to test the impact absorbing properties of eight commercial hip pads. Using an artificial femur with composite materials that composed of cortical and cancellous region, impact load was applied to greater trochanter of the femoral model. Impact absorbing performance was evaluated by the impulsive force, collision time and impact strain. As a result, a hip pad with hard shell showed the best absorbing performance in eight specimens.

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A new method for identifying rigid link models of human lower limbs has been proposed in this paper. The method was motivated by necessity of simulating human body movements for rehabilitation or for design of assistive devices. The method is based on coprime factorization and linear fractional transformation (LFT). Simulation results are given to illustrate the effectiveness of the proposed method.

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Generally, joint moment of human body is measured by using 3D motion analysis system and force plate. However, such a system is very expensive and size of system is very large. In this paper, we propose a new method for measuring ankle joint moment and reaction force by using wearable plantar pressure sensors. Also to make the calibration method easier, we propose a new simple estimation algorithm. Experimental study is carried out and it can be seen that experimental results of the proposed method compare well with the results of conventional method.

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Ankle-foot orthosis (AFO) is a primal aid for patients with gait disorder. Mechanical characteristics of AFO joint directly affect the walking function, and the viscoelasticity of AFO joint might be changed during gait, at least for stance/swing phases respectively. In this article, we designed an AFO joint with MR-fluid so that the viscosity alternated in accordance with the shank angular velocity. We observed the gait with the prototyped AFO of a hemiplegic patient using a shoehorn type AFO in his daily life. It was shown that the shank angular velocity remarkably reduced at the period of heel contact to foot flat, and that the ankle plantar flexion pattern at the initial stance phase becomes more similar to that of people without disability than with his own AFO.

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Measuring of conduction velocity of muscle fibers is one of methods to evaluate the fatigue and the constitution of muscle fibers. In order to measure the conduction velocity by surface electrode arrays, if direction of the muscle fiber istnot definite, we cannot obtain accurate results. In this study, myoelectric characteristics were measured in right biceps bracii during isometric contractions, and the conduction velocity was estimated by using correlation of measured myoelectric patterns. Additionally, the electromyogram was obtained in various angles, in order to know the effect of difference of angle between muscle fiber and electrode arrays axis on the conduction velocity estimation. During sustained isometric contractions with. 50% MYC, the muscle fatigue was estimated using conduction velocity.

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We developed the hybrid electrical stimulation method to improve conventional electrical stimulation ones. Long-term bed rest patients and astronauts in the space show, disuse atrophy due to microgravity exposed. This hybrid method is highly effective against the disuse atrophy. The hybrid method has features as follows: 1) electrical stimulated antagonist muscles are used to resist volitional contractions of opposing agonists and 2) both muscle contractions can generate a compressive load to the direction of a long axis of bone. We applied this hybrid method on 4 healthy men (23±1 years) for 4 weeks. We found that MVC and BMD increased by hybrid exercise.

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This study was designed to examine the effects of length changes in ankle dorsiflexor, tibialis anterior, on the muscular activities, using the mechanomyogram (MMG), electromyogram (EMG) force output during isometric ramp contractions. The relationships between the root-mean-squared amplitude (RMS) of the MMG and relative force (% MVC) in the dorsiflexed ankle and plantarflexed ankle were markedly different from those in the neutral positioned ankle. Although the RMS amplitude of EMG in the dorsiflexed ankle demonstrated the wide difference from those in the neutral positioned ankle, those in the plantarflexed ankle showed the almost same pattern as in the neutral positioned ankle. These changes in EMG and MMG would suggest that the changes in length of muscle probably influence the muscle activation pattern during isometric ramp contraction.

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In recent years, increasing of concern about social welfare, artificial limbs are asked for not only their appearance but also their functions. We developed 'Training Simulator for EMG Prosthetic Hand' using artificial neural network so that it was operated by the EMG of survival muscles. Because the EMG dose not consistent depending on day and muscle conditions, etc., and activities of muscle are synergetic. In this study the EMG data during a short period were gathered through 2 or 4 channels and averaged to improve the recognition rates. We made the neural network learn a stop and three motion patterns with a good recognition rate, about 5%. Human interfaces including control between severed and artificial hands are indispensable to move the artificial hand unconsciously.

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A basic study of a system guiding visually handicapped people with sound signals was conducted. The system utilizes flat panel speakers for their favorable characters such as structural robustness, low cost, space saving and high radiation efficiency. To guide people into desired direction, a method in which multiple speakers are consecutively driven with short time delays was investigated. Our panelists were able to identify the desired sound source location by socalled preceding effect produced by this method, and eventually were guided to the planned destination.

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It is hard to early detect somnipathy such as sudden death (SD), sleep apnea syndrome (SAS), and obstructive sleep apnea (OSA) because the patients don't aware of the subjective symptoms. Then, it is needed to develop a vital-sign monitoring system which can measure the vital signs in a sleep state over the long period. In this paper, we develop a belt type sensor that can measure the signals of respiration, heartbeat, and ECG in a sleep state by using conductive fibers and a Polyvinylidene Fluoride (PVDF). Since the sensor is a belt type, it can be attached with the patients with a minimum invasion. In order to verify the effectiveness of the sensors, we measure not only the signals from the sensors but also that from the commercially available sensors. The results show the validity of our approaches.

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The voice is important in our life. The patient who removed own larynx due to cancer loses the voice. The voice of various substitutions is designed, and, up to now, it has been used by the functional disorder person. A functional disorder person uses the uttered esophageal speech method. This method vibrates the mucous membrane of the vocal tract as a substitute voice. However, there are problems which tone quality is bad and difficult to hear speech. Therefore, it is necessary to correct the vocal chords vibration signal and to generate a plain voice. In this study, we try to make the speech production by correcting the vocal chords vibration signal by the voice tract filter characteristics.

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In recent announcement, the number of households with elderly people exceeded about 7 million for the first time in Japan. As it, the number of elderly pepole living alone is on the increase. Therefore, the system which can monitor the living status of them is desired. From such background, we propose the system which can monitor the living status of elderly people living alone from the use situation of plural home electric appliances. This system can detect a use situation of them, without remodeling the existing home appliances. The result of the field experimented, it was possible to monitor the living status accurately from the use situation of plural home electric appliances.

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The necessity of treating three dimensions, such as a robot and a computer, has increased. It is important for human to make a safe and Comfortable man-machine interface that is easy to use. There is the method of combining equipments that have 1 or 2 degrees of freedom, such as a mouse, a joystick, a dial switch, and an arrow key, in the usual 3-dimensional position inputting method. Furthermore, a 3-dimensional digitizer measures the position in the real world directly. These have the-problem "the direction which can be operated at once is limited", and "the work space equivalent to the width of virtual space is required". Moreover, it is hard to input delicate operation. Then, we propose the input equipment of 6 degrees of freedom with linear-potentiometer. This equipment can input a spatial vector intuitively in one operation.

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The mechanism of peculiar motion of single polar flagellated bacteria swimming close to a wall is investigated. Recent observations have revealed that, when the bacterium swims close to the wall, it swims backward along a curved path and forward straightly. Furthermore, the speeds of forward and backward motions are different despite of that associating inertial forces are negligible. Numerical results of boundary element analyses show that these phenomena are mainly due to fluid dynamic effect of the wall which induces the difference in pitching stability between the forward and backward motions, that is, forward motion is stable, backward unstable.

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Deformation of Salmonella flagellum is analyzed considering the flagellum as a hollow cylinder which consists of 11 flagellin filaments. The torsional and bending moment in the cross section of the flagellum are obtained from viscous force exerted by the flow on the surface of the flagellum. The curvature and the torsion of the deformed flagellum are obtained according to the Kirchhoff elastic rod model. The elastic bending coefficient of Salmonella flagellum is estimated comparing the present numerical results with the experimental results of Hoshikawa et al.

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Flagella and cilia of eukaryotic cells are autonomous machinery to propel small cells in the medium under the condition of low Reynolds' number. Since they can keep almost constant activity and wave patterns in a wide range of viscosity, the intrinsic mechanism of motion control seems to be working well by modifying the activity of dynein motors depending on given viscosity loads. Therefore, one of the most crucial points to be clarified to understand the mechanism is the exact description of viscosity effects on the motion. In the present study, I developed a new method to observe the planar beats of sea-urchin (Anthocidaris crassispina) sperm flagella under two-dimensional conditions, i.e., a thin liquid film formed in a modified Mysels' cell. By the new method, it is expected that the analysis of fluid dynamics can be simplified, and that we can observe the motion in a wide range of viscosity load comparing with conventional methods.

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Objective of this study is to understand dynamics of amoeboid cells through a numerical simulation of motion. Cell structures are represented by a mass-spring-dashpot system presenting a cell membrane, cytoskeletal filaments and internal net structure constructed by intermediate filamnets. These structures are distinguished by stiffness, damping coefficient and mass of the system. Frequency response to forcing for different cases is shown in this paper. This model is effective to show the similar motion as that of amoeboid cells.

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We have carried out the prediction of dynamic behavior of ion conducting polymer actuator by bondgraph method. The energy flow in the ion conducting polymer actuator was divided into the electrical model and mechanical model by bondgraph and we have carried out the simulation of current and displacement of actuator. Moreover, we have performed the experimental measurement of them under the condition of four cations, such as Li^+, K^+, Na^+, Cs^+. The bondgraph simulation results were in good agreement with the experimental results qualitatively and quantitatively. Furthermore, the qualitative electrical and mechanical characteristics of each ion are clarified by the derived each coefficients of bondgraph.

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Purpose: Using PIV, we visualized the velocity field around swimmer's hand and analyzed the vorticity generated by hand. Methods: Experiments were carried out in a swimming flume. We used YAG laser sheet to illuminate the tracer particles around the swimmer's arm. The images were captured by a CCD camera and stored in a personal computer. We made the image map and the vector and vorticity map. Results: The larger and stronger swimmers make the vortex, the larger the momentum is generated around a hand. In S-shaped pull, we can detect the negative vorticity near a thumb in in-sweep phase, and the positive vorticity near a small finger in out-sweep phase. Conclusion: we succeeded the visualization around swimmer's arm for the first time. We clarified the unsteady flow field around the arm, and evaluated the force generated by the hand qualitatively.

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In this study, shape optimization of fish tail propulsion considering hydro-elastic effects has been carried out. MDLM (Modified Doublet Lattice Method) is used for the flow analysis. It is based on DLM (Doublet Lattice Method), which is suitable for the calculation of unsteady fluid force for an arbitrary shape of wing. As DLM does not consider the leading-edge suction, DLM is improved to calculate the leading-edge suction at the same time. ANS (Adapted Neighboring Search), has been extended for multiple objectives and used to optimize the tail shape and movement to maximize the thrust coefficient and the propulsive efficiency.

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A numerical method for moving and deformation grid in the three dimensional flow is developed The arbitrary Lagrangian-Eulerian method is employed. The scheme is fourth-order accurate in space and uses the momentum equations for the velocity coupled to a Poisson equation for the pressure. The fourth-order consistent scheme and 2nd order Adams-Bashforth method are applied to the convective terms in the Navier-Stokes equation. In this investigation, the flow around periodic bending flat plate is computed. We present numerical results, which demonstrate that the controlled actuation of the caudal fin and release of vortex to the efficient production of inverse Karman vortex street.

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The authors developed a Manta-like submergence vehicle. This vehicle is 0.7 m at length, has a couple of levelly-placed fins and is expected to perform up-down motion by making use of fluid force. The vehicle performs forward, turn, and up-down motion by pitching one or two fins. It uses radio control for manipulation. In the result of swimming performance experiments, the vehicle swam at about 0.2 m/s which is about one fifth of body length per second. And-it turned by stopping one fin, and showed up-down continual motion by pitching fins with its vibration center placed above or below the body center. Therefore, swimming performance expected by the authors is almost achieved.

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A horizontal oscillating wing with a fish-like tail fin stroke has been proposed as a novel propulsion system with higher propulsive efficiency and higher safety than a conventional screw propeller. This paper describes the development of an outboard oscillating horizontal wing propulsor that is easy to attach to and detach from a small boat The heaving and pitching motions of the oscillating wing was obtained by designing a new crank mechanism with L-shaped links. The propulsive performance of the outboard oscillating wing propulsor mounting a reflection panel over the wing was investigated. The outboard oscillating wing propulsor has potential to be an environmentally friendly propulsor for small boats such as fishing and pleasure boats.

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For the purpose of measuring the forces and moments on flapping wing, mechanical flapping robot MOTH-1 was developed. It can generate insect-like flapping motion and measure the 5-units of forces and moments acting on its wings. We used hawknioth motion data as an input of robot and measured the forces and moments acting on its wings. The results indicated the relationship between time-wise variation of wing motion and its generating forces and moments, thus yielding useful data for analysis of aerodynamics of flapping wings.

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We have developed a biology-inspired dynamic flight simulator on a basis of realistic insect morphology which is capable to mimic free flight of a real insect. It aims at analyzing the aerodynamic phenomena associated with the insect free flight and revealing the force-generation mechanisms. Using a moth, Agrius convolvuli LINNE, we have made a digitizing analysis of the shape and the internal structure of insect wings and body, and succeeded in constructing a realistic wing-body moth model with high resolution. A CFD modeling of unsteady aerodynamics in a flapping flight is also established.

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A numerical rigid multi-body modeling of free flight insect has been developed, emphasis on preserving the angular momentum and energy of the whole system. And the experimental method of obtaining the kinematic parameters is explained sequentially. Then the numerical solution of 3D Navier-Stokes equations with finite volume method is given a brief description. Finally, the preliminary discussion is addressed, which emphasizes particularly on the contribution of the inertial force to the variation of flight attitude and to the ftight control.

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Indirect-flight-insects' flying mechanism has not yet been fully recognized, though our results lead a hew mechanical model of resonance, which consists of a string and a picking mechanism. The former means the wings and thorax and the latter means the wing drive muscle. This mechanical model showed the same, frequency of the bee. Using micro X-CT, a new structural approaches attempting.

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The purpose of this study is to investigate flow pattern around mosquito's wing while it is beating. We constructed an experimental apparatus to simulate the beating motion of mosquito. An enlarged scale model experiment was carried out using a very low speed wind tunnel under the condition that Reynolds number and Strouhal number were made equal to those of real mosquito. The flow field around the wing model moving up and down was visualized using smoke and laser light sheet and it was analyzed by a PIV system. Unsteady vortices were observed to be generated on the upper surface of the model wing in the period of downstrdke. We compared the vortices each other on three different kinds of enlarged scale models (8, 10, 12.5 times). As a result, the flow fields around the wings were almost same regardless of the enlargement scale at the same Reynplds number and Strouhal number condition of symmetrical wing model.

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This paper presented the results of an experimental investigation of droplet impacting on dragonfly wings. The collision characteristics of dragonfly wings are studied with a digital high speed camera system. The results are presented for different impact velocities and different impact locations on dragonfly wings. The results show the marvelous structure of dragonfly wings for the rain drop collision. It was found that dragonfly wings have the flexible response and the water repellency for the water drop collision. The drop collision phenomena on dragonfly wings are also revealed.

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The puipose of our study is to apply Mosquito's sucking blood mechanism to a pump and a channel of μ-TAS for checking blood. We want to know how high the power of Mosquito's pump is and how small the resistance in a needle is. This paper presents a structure of Mosquito's bio-pump, and its characteristics as mechanical pump. We made the mosquito feed blood of our arm. Pictures are taken by SEM, and many slices of a mosquito with 2μm thickness after fixed by wax were made. We anatomized the mosquito's head and picked up the bio-pump under the microscope. The mosquito's bio-pump is found to be enough power to apply a pump of μ-TAS.

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The shoulder joint is surrounded by the rotator cuff, which keeps it stable. When rotator cuff tear occurs, stress distribution on the joint surface will change. Diseased stress situation causes osteoarthritis of the shoulder. Computer simulation is useful to estimate the effect of the operation for rotator cuff tear. In this study, we made three dimensional finite element model of the glenohumeral joint from CT data. Stress distribution on the joint surface was analyzed for normal, rotator cuff tear, and teres minor transfer models. In addition new glenoid components were compared in total shoulder orthroplasty models. As a result, in supraspinatus tear model, the stress distribution was almost same as normal model. In both supraspinatus and infraspinatus tear model, the stress value increased. In teres minor transfer model, the stress distribution approached to normal model. In new glenoid component model, stress distribution on bone-cement interface decreased, but high tensile stress was confirmed on the joint surface.

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Technique to make patient specific finite-element models of bone representing bone density distribution by using CT images has been established. The patient specific modeling is expected for application in clinics of orthopedic surgery and human injury analysis of traffic accident. In particular, pelvic finite-element models, which have high bio-fidelity in viewpoint of pelvic shape, cortical thickness, bone mass density, etc, are required for pelvic fracture analysis of pedestrian collision in traffic accident. Although the technique of CT image based modeling is also available for pelvis, validity of the pelvic FE model has not sufficiently studied in mechanical viewpoint. In this study, individual finite-element model of coxal bone based on x-ray CT image data was created. The coxal model has not only correct shape but also bone mass density distribution. Strain of coxal bone surface analyzed by the finite-element model was compared with corresponding strain measured in loading experiment, and validity of the model was discussed.

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In this study, the construction method using the hexahedral meshes is proposed in order to build the three-dimensional finite element models. The several 'Seed' meshes that were constituted by hexahedral elements were located into the inside of the surface model of knee joint using CT slice images. On the meshing process, the seed meshes expanded to fit the inside of the model surface. The results of the hexahedral constructions for the knee joint model were compared with those of tetrahedral ones. As the result, the number of element by the hexahedral meshing is less than a quarter of that by the tetrahedral one.

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Femoral resurfacing implantation is alternative option to total hip replacement for the surgery of femoral head osteonecrosis. Although it was developed first in the 1970s, it did not come into wide use because postoperative stability was not sufficient for a long period. Femoral resurfacing implantation has been attracted the attention of orthopedic surgeon again, since material and design technology has been recently progressed In this study, finite-element models of femoral head replacement with the resurfacing implantation were created based on clinical CT images, and stress analyses were carried out considering inhomogeneous property of bone. Furthermore, influence of stress distribution around the femoral head with arrangement of the resurfacing implant was investigated by changing position of the implantation.

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We investigated the stress conditions and growth deformation behaviors in the dental roots of three teeth mounted with the crown bridge using the growth strain method. The growth analysis of these analytical models was determined by applying two-dimensional finite element method. At first, criterion parameters of alveolar bone and dentin were defined by the mean value of strain energy density in each total element. Next, growth strain analysis of the each analysis model was performed under the growth criterion parameters of the alveolar bone and dentin. Our findings showed the final shape of the tooth with the crown bridge was remodeling so that bone absorption was hard to occur on the dental roots.

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A computational simulation for trabecular bone remodeling using a voxel FEM, in which resorption and formation on the trabecular surfaces are directly expressed by removal and addition of the voxel elements, have a numerical limitation depending on the discretized element size. To remove this restriction, in this study, a level set method was introduced for smooth surface movement due to the trabecular remodeling combining with the voxel FEM. The proposed method was compared with the conventional voxel method through a case study of remodeling simulation for a single trabecula under uniaxial compressive loading. As a result, it was demonstrated that the proposed technique using a level set method could enable us to express the smooth surface movement of trabecula without dependence on the discretized element size.

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To realize a reliable simulation of biological soft tissues, we have to understand its complicated mechanical property, which can be hardly obtained by the conventional material testing. Proposed here is a new method of three-dimensional deformation measurement by integrating the X-ray CT system and the material testing machine. This system provides the three-dimensional images of the specimen in initial and deformed states. By comparing these two images, we identify the displacement field inside the specimen, and consequently obtain the strain field. The basic concept is based on the digital image correlation method. However, the CT image has few patterns to be matched between initial and deformed images, and soft tissues allow intricately distributed large deformation. To overcome such difficulties, we make use of the B-spline functions as the basis functions of displacement field and the Levenberg-Marquardt method as a fast solver for the correlation calculation on the three-dimensional images, which constitutes a large-scale nonlinear programming problem.

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The use of the ultrasound-imaging platform in medical facilities has significantly increased in recent years due to its superior capability, namely high resolution, small influence to the human body and so on. Though the doctors diagnose a tissue characterization of a liver by observing an image obtained by ultrasound, a diagnostic result seems to make a difference with experience of doctors. Therefore a quantitative analysis method concerning ultrasonography is required. This paper proposes a CAD (Computer Aided Diagnosis) by a neural network, which diagnoses a tissue characterization of liver. This system studies three kinds of teacher signal (conditions of liver: normal, chronic hepatitis and liver cirrhosis). As a result, this system is confirmed that it can distinguish between normal of liver and liver cirrhosis. Our future purpose is the discriminate accuracy improved by increasing the pattern of neural network system.

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As the material of recent catheter, which is used in the operation such as the myocardium infarction, not only a soft characteristic but also the responsiveness and the operationally are required in order to carry out the remote operation smoothly. The purpose of this study is to investigate the deformational behavior and strength of catheter, which is made from the nylon resin braided by a thin stainless wire. In this paper, we propose the analytical model in consideration of the geometric relation of a braid and we decide Young's modulus. And, the validity of this model is confirmed by comparing numerical results with experimental results. Furthermore, performing numerical simulations with various braid angles, we investigate a viscoelastic response of the catheter under uni-axial tension.

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Generally, as the material of catheter, soft characteristic is required so as not to damage vascular wall etc. On the other hand, in the surgical operations that the remote manipulation is required such as myocardial or cerebral infarction, a responsibility and enough stiffness are also needed. When we image actual use of catheter, it is expected that the deformation is multiaxial loading state of tension, torsion, and bending. However, it is difficult to elucidate these mechanical property directly. So, we must investigate it from not complicated deformation but simply uniaxial loading. In our previous study, we have been tried to investigate the physical property of tension. In this paper, tosional tests have been carried out to investigate viscoelastic response. Moreover, we discuss the relation of the shearing modulus and braid angle.

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The purpose of this study is to propose a computer simulation method using particle method to analyze aggregation process of platelets in blood flow. We applied the MPS method, which has been developed for incompressible fluid based on Navier-Stokes equations, to plasma flow analysis. Adhesion of platelets to exposed subendothelium was modeled by introducing attractive force between the platelets and the injured wall. In addition, force acted on among aggregated platelets was considered to express the deformation of the aggregation as a solid. Two-dimensional simulations revealed that the proposed method expresses initial thrombogenesis, growth of the thrombus, and the destruction of thrombus. It was shown that the Reynolds number affects the number of the aggregated platelets, indicating fluid mechanical factors play an important role in thrombosis caused by platelets aggregation.

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Particle simulations of elastic line motion in water were carried out. Images of Loach motion were analyzed and simplified to use as input to simulation Simulation model treats both water and solid as particles. Water particles were moved by interparticle force potential, while solid particles were moved based on the image analysis and elastic force by spring. Solid particles and water particles interact forming flow pattern, and loach move forward by driving force.

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