Academic literature on the topic 'Ankle – Mechanical properties'
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Journal articles on the topic "Ankle – Mechanical properties"
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Sinkjær, Thomas, Nikolai Gantchev, and Lars Arendt-Nielsen. "Mechanical properties of human ankle extensors after muscle potentiation." Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section 85, no. 6 (December 1992): 412–18. http://dx.doi.org/10.1016/0168-5597(92)90055-g.
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Martelli, Taborri, Del Prete, Palermo, and Rossi. "Quantifying Age-Related Differences of Ankle Mechanical Properties Using a Robotic Device." Robotics 8, no. 4 (November 13, 2019): 96. http://dx.doi.org/10.3390/robotics8040096.
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A deep analysis of ankle mechanical properties is a fundamental step in the design of an exoskeleton, especially if it is to be suitable for both adults and children. This study aims at assessing age-related differences of ankle properties using pediAnklebot. To achieve this aim, we enrolled 16 young adults and 10 children in an experimental protocol that consisted of the evaluation of ankle mechanical impedance and kinematic performance. Ankle impedance was measured by imposing stochastic torque perturbations in dorsi-plantarflexion and inversion-eversion directions. Kinematic performance was assessed by asking participants to perform a goaldirected task. Magnitude and anisotropy of impedance were computed using a multipleinput multiple-output system. Kinematic performance was quantified by computing indices of accuracy, smoothness, and timing. Adults showed greater magnitude of ankle impedance in both directions and for all frequencies, while the anisotropy was higher in children. By analyzing kinematics, children performed movements with lower accuracy and higher smoothness, while no differences were found for the duration of the movement. In addition, adults showed a greater ability to stop the movement when hitting the target. These findings can be useful to a proper development of robotic devices, as well as for implementation of specific training programs.
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Becerra, J. G. Flores, N. López Perrusquia, M. A. Doñu Ruiz, A. López Perrusquia, and J. V. Cortes Suarez. "Study of Microstructure and Mechanical Properties of an Ankle Prosthesis Removing." MRS Proceedings 1766 (2015): 19–25. http://dx.doi.org/10.1557/opl.2015.408.
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ABSTRACTThis work studies the change microstructural and mechanical properties of an ankle prosthetic material 316LVM stainless steel, retired from a 36 year old patient. The medical grade 316LVM stainless steel was characterized by scanning electron microscopy (SEM), optical microscopy (OM), X-ray diffraction (XRD), hardness Rockwell C (HRC) and nanoindentation tests. The results showed that the ankle prosthesis has different microstructural change along the implant and presence of corrosion pits with inclusions, the mechanical properties like modulus elasticity and hardness decrease.
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Sheehan, Conor, and Elaine Figgins. "A comparison of mechanical properties between different percentage layups of a single-style carbon fibre ankle foot orthosis." Prosthetics and Orthotics International 41, no. 4 (June 30, 2016): 364–72. http://dx.doi.org/10.1177/0309364616652015.
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Background:Currently, a range of ‘off-the-shelf’ ankle foot orthoses are used in clinical practice, of various functions and designs. Their use relates to immediate control over mild conditions.Objectives:To investigate the properties of carbon fibre ankle foot orthoses at different percentage layups and provide a comparison of these through assessment of the (1) elastic properties, (2) deflection about the ankle (including the calculation of stiffness) and (3) failure under compressive forces (dorsiflexion).Study design:Experimental, bench test.Methods:Literature was reviewed to derive a suitable bench test for mechanical testing of ankle foot orthoses. Two universal Instron machines were used to apply the necessary forces. A pilot device was utilised to establish the range of forces appropriate to confirm the setup chosen was effective. Each test was then carried out on nine ankle foot orthoses (3 × 3 different percentage layups).Results:All nine devices had their elastic properties deduced. Stiffness exhibited greater resistance in tension, with angular deflection being greatest in the ‘Lite’ set and least in the Rigid. Failure occurred mainly due to fracture, proximally on the strut; however, this was not consistent among the devices.Conclusion:Results confirmed the properties expected of carbon fibre ankle foot orthoses were consistent. This can now be related to functionality and therefore specific device prescription options.Clinical relevanceThis article attempts to increase the understanding and develop the area of mechanically testing ankle foot orthoses. This was achieved by comparing carbon fibre at different percentage layups on an identical design and their resultant structural properties. This article outlines a clear and simple setup for obtaining repeatable results.
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Wang, Ruoli, Shiyang Yan, Marius Schlippe, Olga Tarassova, Gaia Valentina Pennati, Frida Lindberg, Clara Körting, et al. "Passive Mechanical Properties of Human Medial Gastrocnemius and Soleus Musculotendinous Unit." BioMed Research International 2021 (February 9, 2021): 1–12. http://dx.doi.org/10.1155/2021/8899699.
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The in vivo characterization of the passive mechanical properties of the human triceps surae musculotendinous unit is important for gaining a deeper understanding of the interactive responses of the tendon and muscle tissues to loading during passive stretching. This study sought to quantify a comprehensive set of passive muscle-tendon properties such as slack length, stiffness, and the stress-strain relationship using a combination of ultrasound imaging and a three-dimensional motion capture system in healthy adults. By measuring tendon length, the cross-section areas of the Achilles tendon subcompartments (i.e., medial gastrocnemius and soleus aspects), and the ankle torque simultaneously, the mechanical properties of each individual compartment can be specifically identified. We found that the medial gastrocnemius (GM) and soleus (SOL) aspects of the Achilles tendon have similar mechanical properties in terms of slack angle (GM: − 10.96 ° ± 3.48 ° ; SOL: − 8.50 ° ± 4.03 ° ), moment arm at 0° of ankle angle (GM: 30.35 ± 6.42 mm; SOL: 31.39 ± 6.42 mm), and stiffness (GM: 23.18 ± 13.46 Nmm-1; SOL: 31.57 ± 13.26 Nmm-1). However, maximal tendon stress in the GM was significantly less than that in SOL (GM: 2.96 ± 1.50 MPa; SOL: 4.90 ± 1.88 MPa, p = 0.024 ), largely due to the higher passive force observed in the soleus compartment (GM: 99.89 ± 39.50 N; SOL: 174.59 ± 79.54 N, p = 0.020 ). Moreover, the tendon contributed to more than half of the total muscle-tendon unit lengthening during the passive stretch. This unequal passive stress between the medial gastrocnemius and the soleus tendon might contribute to the asymmetrical loading and deformation of the Achilles tendon during motion reported in the literature. Such information is relevant to understanding the Achilles tendon function and loading profile in pathological populations in the future.
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Ielapi, Alessio, Malcolm Forward, and Matthieu De Beule. "Computational and experimental evaluation of the mechanical properties of ankle foot orthoses: A literature review." Prosthetics and Orthotics International 43, no. 3 (January 31, 2019): 339–48. http://dx.doi.org/10.1177/0309364618824452.
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Background: Ankle foot orthoses are external medical devices applied around the ankle joint area to provide stability to patients with neurological, muscular, and/or anatomical disabilities, with the aim of restoring a more natural gait pattern. Study design: This is a literature review. Objectives: To provide a description of the experimental and computational methods present in the current literature for evaluating the mechanical properties of the ankle foot orthoses. Methods: Different electronic databases were used for searching English-language articles realized from 1990 onward in order to select the newest and most relevant information available. Results: A total of 46 articles were selected, which describe the different experimental and computational approaches used by research groups worldwide. Conclusion: This review provides information regarding processes adopted for the evaluation of mechanical properties of ankle foot orthoses, in order to both improve their design and gain a deeper understanding of their clinical use. The consensus drawn is that the best approach would be represented by a combination of advanced computational models and experimental techniques, capable of being used to optimally mimic real-life conditions. Clinical relevance In literature, several methods are described for the mechanical evaluation of ankle foot orthoses (AFOs); therefore, the goal of this review is to guide the reader to use the best approach in the quantification of the mechanical properties of the AFOs and to help gaining insight in the prescription process.
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Siegler, Sorin, John Block, and Carson D. Schneck. "The Mechanical Characteristics of the Collateral Ligaments of the Human Ankle Joint." Foot & Ankle 8, no. 5 (April 1988): 234–42. http://dx.doi.org/10.1177/107110078800800502.
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In the present study, the tensile mechanical properties of all of the collateral ligaments of the human ankle joint were determined, in vitro, from tensile tests conducted on 120 ligaments obtained from 20 fresh lower limbs. The ultimate load of the lateral collateral ligaments increased in an anteroposterior sequence, with the anterior fibulotalar ligament less than the fibulocalcaneal ligament and less than the posterior fibulotalar ligament. For the medial collateral ligaments, the increasing order of ultimate load was found to be tibiocalcaneal ligament, tibionavicular ligament, tibiospring ligament, posterior tibiotalar ligament. The posterior tibiotalar ligament and tibiospring ligament, so frequently neglected in the anatomical and orthopaedic literature, demonstrated the highest yield force and ultimate load of all of the collateral ligaments of the ankle. Additionally, the tibiospring ligament showed high yield and ultimate elongation properties probably related to its distal attachment to the spring ligament. The fibulocalcaneal ligament was found to have high linear elastic modulus suggesting some type of unique material properties or internal fiber organization. Knowledge of the mechanical characteristics of the ligaments of the ankle joint contributes to an understanding of their normal function, pathomechanics of injury, and their optimal surgical reparative procedure and reconstructive material. A knowledge of the normal mechanical properties of the ankle ligaments provides a data base to evaluate which of the multiplicity of present tendon graft materials has mechanical properties similar to those of the ligaments to be replaced. Those tendon grafts will be the most suitable for replacement of specific ligaments. Finally, data on the mechanical properties of these ligaments offer the possibility for evaluating any future biological or prosthetic grafts.
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Jeryo, Abbas H., Jumaa S. Chiad, and Wajdi S. Abbod. "Boosting Mechanical Properties of Orthoses - Foot Ankle by Adding Carbon Nanotube Particles." Materials Science Forum 1039 (July 20, 2021): 518–36. http://dx.doi.org/10.4028/www.scientific.net/msf.1039.518.
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In this process, optimum laminating properties were used in producing prosthesis and orthoses were researched and selected based on high yield, ultimate stresses, stresses of bending and fatigue properties. The process of the optimal selection is the Response Surface Methodology (RSM), which has been used to reach two parameters: reinforcement perlon fiber and percent of multi-strand carbon MWCNT nanotube combined with the matrix resin. The response surface methodology is a combination of mathematician and statistic techniques which are used for experimental model building and analysis of problems. This technique revealed 13 separate laminations samples with a percentage of separate Perlon layers No. and MWCNT Wt %. Tests were conducted for all lamination materials as defined in RSM methods and rendered by vacuum system, including fatigue tests for the ideal laminating material as opposed to laminations developed in the prior study (three Tensile test, Bending test and Fatigue tests according to the ASTM D638 and D790 respectively). Tests from the system version 10.0.2 of Design Expert found lamination (10 perlon layers and 0.75% of MWCNTs) to be the best according to overall yield, ultimate and bending loads in the 12 other laminations. Fatigue eventually revealed that constraints were applied to the stamina tension (2,66, 1,66) for optimum lamination, relative to ten perlon lamination layers and 424 lamination respectively.
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Kovaleski, John E., Robert J. Heitman, Larry R. Gurchiek, J. M. Hollis, Wei Liu, and Albert W. Pearsall IV. "Joint Stability Characteristics of the Ankle Complex After Lateral Ligamentous Injury, Part I: A Laboratory Comparison Using Arthrometric Measurement." Journal of Athletic Training 49, no. 2 (March 1, 2014): 192–97. http://dx.doi.org/10.4085/1062-6050-49.2.07.
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Context: The mechanical property of stiffness may be important to investigating how lateral ankle ligament injury affects the behavior of the viscoelastic properties of the ankle complex. A better understanding of injury effects on tissue elastic characteristics in relation to joint laxity could be obtained from cadaveric study. Objective: To biomechanically determine the laxity and stiffness characteristics of the cadaver ankle complex before and after simulated injury to the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) during anterior drawer and inversion loading. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: Seven fresh-frozen cadaver ankle specimens. Intervention(s): All ankles underwent loading before and after simulated lateral ankle injury using an ankle arthrometer. Main Outcome Measure(s): The dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness. Results: Isolated ATFL and combined ATFL and CFL sectioning resulted in increased anterior displacement but not end-range stiffness when compared with the intact ankle. With inversion loading, combined ATFL and CFL sectioning resulted in increased range of motion and decreased end-range stiffness when compared with the intact and ATFL-sectioned ankles. Conclusions: The absence of change in anterior end-range stiffness between the intact and ligament-deficient ankles indicated bony and other soft tissues functioned to maintain stiffness after pathologic joint displacement, whereas inversion loading of the CFL-deficient ankle after pathologic joint displacement indicated the ankle complex was less stiff when supported only by the secondary joint structures.
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Kobayashi, Toshiki, Fan Gao, Nicholas LeCursi, K. Bo Foreman, and Michael S. Orendurff. "Effect of Shoes on Stiffness and Energy Efficiency of Ankle-Foot Orthosis: Bench Testing Analysis." Journal of Applied Biomechanics 33, no. 6 (December 1, 2017): 460–63. http://dx.doi.org/10.1123/jab.2016-0309.
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Understanding the mechanical properties of ankle-foot orthoses (AFOs) is important to maximize their benefit for those with movement disorders during gait. Though mechanical properties such as stiffness and/or energy efficiency of AFOs have been extensively studied, it remains unknown how and to what extent shoes influence their properties. The aim of this study was to investigate the effect of shoes on stiffness and energy efficiency of an AFO using a custom mechanical testing device. Stiffness and energy efficiency of the AFO were measured in the plantar flexion and dorsiflexion range, respectively, under AFO-alone and AFO-Shoe combination conditions. The results of this study demonstrated that the stiffness of the AFO-Shoe combination was significantly decreased compared to the AFO-alone condition, but no significant differences were found in energy efficiency. From the results, we recommend that shoes used with AFOs should be carefully selected not only based on their effect on alignment of the lower limb, but also their effects on overall mechanical properties of the AFO-Shoe combination. Further study is needed to clarify the effects of differences in shoe designs on AFO-Shoe combination mechanical properties.
Dissertations / Theses on the topic "Ankle – Mechanical properties"
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Dewan, Curt. "Biomechanics of the foot and ankle during ice hockey skating." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81326.
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This study describes the biomechanics of the foot and ankle during the transitional and steady state skating strides using kinematic, kinetic, and myoelectric measures. A data set for five collegiate hockey players was completed (mean +/- SD: age = 21.8 +/- 1.9 years, height = 1.81 +/- 0.05 m, mass = 83.3 +/- 8.0 kg). Three acceleration strides and a constant velocity stride were examined on ice. An electrogoniometer at the ankle was used to measure angular displacement and velocity values. Myoelectric activation patterns were measured at the vastus medialis, tibialis anterior, peroneus longus, and medial gastrocnemius of the right lower limb. Kinetic pressure profiles were measured using piezo resistive fabric sensors providing accurate pressure measurement within the narrow confines of the skate boot-to-foot/ankle interface. Sixteen flexible piezo-resistive sensors (1.2 cm x 1.8 cm x 0.2 cm thick) were taped to discrete anatomical surfaces of the plantar, dorsal, medial and lateral surface of the foot, as well as to the posterior aspect of heel and leg. Repeated measures ANOVAs and Tukey post hoc tests found few significant differences among stride variables; however insights into the mechanics of ice hockey skating at the foot and ankle are given.
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Toy, Jason Robert Siegler Sorin. "Subject specific models of the hindfoot reveal a relationship between morphology and passive mechanical properties /." Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3183.
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Chinworth, Susan A. (Susan Annette). "Ground Reaction Forces and Ankle and Knee Moments During Rope Skipping." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc501047/.
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Ground reaction force (GRF) data collected and synchronized with film data to determine peak GRF and calculate moments about ankle and knee during rope skipping. Two, five minute conditions were analyzed for 10 subjects. Condition 1 was set rate and style. Condition 2 was subjects' own rate and style. Means and standard deviations were reported for peak GRF, ankle and knee moments. One way ANOVAs reported no significant difference between conditions for variables measured. Efficiency and nature of well phased impacts during rope skipping may be determined by combination of GRF, similarities in magnitude and direction of joint moments, and sequencing of segmental movements. Technique and even distribution of force across articulations appear more important than magnitudes of force produced by given styles.
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Clanton, Tameka A. "Prophylactic ankle stabilizers and their effect on lower extremity landing mechanics during drop jump landings to fatigue." Muncie, Ind. : Ball State University, 2009. http://cardinalscholar.bsu.edu/644.
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Botha, Jan. "The development of a device for the investigation of dorsiflexion range of the ankle with a capacity to measure pathology, recovery and pharmacological benefit." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/2086.
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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005.Various ways exist whereby balance abilities of the individual can be assessed. However, most of these are subjective methods. This thesis strives to demonstrate the effectiveness of a new device, the Dorsiflexometer that can be used to objectively assess one’s balance abilities. The Dorsiflexometer was constructed and mathematically modelled using appropriate simplifying assumptions. After its construction, the Dorsiflexometer was tested using two experimental set-ups to obtain raw data. Both these set-ups consisted of the two tiltable platforms equipped with three load cells each, the bridge amplifiers and the personal computer (PC). The only difference in the two experimental set-ups is in the type of test that was performed as well as the bridge amplifiers used. Numerous parameters, such as the radius of movement and the Lyapunov number can be extracted from the raw data. A computer program was written to analyse the raw data and present the results in a user-friendly manner. A new parameter, the Sway Index, was used to obtain a single balance value for the tested individual. This parameter proved useful in quantifying balance. An advanced patent search was carried out before the device was constructed. This was necessary to provisionally patent the device – official application number: 2003/6702.
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Skoss, Ann Rachel Locke. "Stabilisation of the human ankle joint in varying degrees of freedom : investigation of neuromuscular mechanisms." University of Western Australia. School of Human Movement and Exercise Science, 2002. http://theses.library.uwa.edu.au/adt-WU2003.0021.
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Previous research investigating the stability of the ankle joint complex may be categorised into two methodological groups, employing either an actuator to perturb the limb, or a form of standing balance disturbance such as a tilting platform, both of which test the joint in single degree of freedom (DOF). The aim of this thesis was to investigate how we control foot position and stabilise the joint when there is potential for movement in three DOF. A secondary aim of the thesis was to model the intrinsic mechanical properties of the ankle joint complex in three dimensions when coupled movement of the tibio-talar and talo-calcaneal joints are possible. This thesis details (i) the development of a perturbation rig that allows foot movement in single- or three-DOF with associated real-time visual target-matching software, and (ii) the use of the rig to investigate the stabilisation of the ankle joint complex in single- and three-DOF. The experimental procedure used a common task performed in three experimental conditions. Subjects were required to maintain a neutral foot position while developing varying levels of plantar-flexion torque. A perturbation was applied to the foot if subjects were within specified tolerance for both foot position and torque, represented by the visual display. Performance of the task in the first condition required the subject to only match torque as the foot position was fixed, with the perturbation being applied in dorsi-flexion (ie, single-DOF). The second experimental condition allowed the foot to move in the sagittal plane, hence subjects were required to control both torque and foot position in single-DOF, with perturbation applied in dorsi-flexion. The third condition enabled movement in dorsi/plantar-flexion, inversion/eversion and adduction/abduction (three-DOF) in both task and perturbation. Subjects were required to maintain the neutral foot position and the necessary torque level. There were three areas of interest common to each experimental protocol. The muscle strategy used to complete the task was investigated using a combination of surface and fine-wire electromyography on lower leg and thigh muscles. The 500ms period prior to perturbation was investigated to determine if synergies were evident between muscles such as medial and lateral gastrocnemius, soleus and peroneus longus. Two classes of activation strategies for the three-DOF condition emerged from the subject population: differential activation of the triceps surae group, and co-contraction. The former strategy may take advantage of the distinct morphology of the lateral gastrocnemius and peroneus longus muscles to best perform the position-matching component of the 3D task. The results suggest that the ankle joint is mostly stabilised in 3D by the intrinsic mechanical actions of the muscles producing plantar flexion moments. The muscles stabilised the foot in inversion, but not in eversion where there was very little motion. However, the different activation strategies employed may have varied efficacy in contributing to joint stability. This form of active stabilisation means that the previous literature focus on reflexes to stabilise the joint may need to be reassessed. Likewise, it may be appropriate to use the perturbation rig to quantify active ankle joint stability in order to assess the probability of ankle injury, rather than the current clinical measures employed. The reflexive response due to the perturbation was examined in the 200ms following perturbation. Variation in the modulation of monosynaptic reflexes was observed between subjects in various muscles in the higher DOF tasks. This is likely due to the differing activation strategies used to perform the task, and the variability in the kinematic response to perturbation. An attempt was made to calculate the intrinsic mechanical properties of the joint in 3-D using the kinematic and kinetic data during the first 15 ms period of perturbation. The system was modelled as a spring-damper using a constrained non-linear least squares, with stiffness and viscous terms for each axis, and inertial tensor elements as variables in the routine. The effect of increased muscle activation on the displacement of the foot about each of the anatomical axes was to significantly lower the movement of the sub-talar joint.
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Ludcke, Justin A. "Modelling of inflatable rescue boats (IRBs) in surf conditions to reduce injuries." Thesis, Queensland University of Technology, 2001.
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The Inflatable Rescue Boat (IRB) is arguably the most effective rescue tool used by the Australian surf lifesavers. The exceptional features of high mobility and rapid response have enabled it to become an icon on Australia's popular beaches. However, the IRB's extensive use within an environment that is as rugged as it is spectacular, has led it to become a danger to those who risk their lives to save others.
Epidemiological research revealed lower limb injuries to be predominant, particularly the right leg. The common types of injuries were fractures and dislocations, as well as muscle or ligament strains and tears. The concern expressed by Surf Life Saving Queensland (SLSQ) and Surf Life Saving Australia (SLSA) led to a biomechanical investigation into this unique and relatively unresearched field. The aim of the research was to identify the causes of injury and propose processes that may reduce the instances and severity of injury to surf lifesavers during IRB operation.
Following a review of related research, a design analysis of the craft was undertaken as an introduction to the craft, its design and uses. The mechanical characteristics of the vessel were then evaluated and the accelerations applied to the crew in the IRB were established through field tests. The data were then combined and modelled in the 3-D mathematical modelling and simulation package, MADYMO. A tool was created to compare various scenarios of boat design and methods of operation to determine possible mechanisms to reduce injuries.
The results of this study showed that under simulated wave loading the boats flex around a pivot point determined by the position of the hinge in the floorboard. It was also found that the accelerations experienced by the crew exhibited similar characteristics to road vehicle accidents. Staged simulations indicated the attributes of an optimum foam in terms of thickness and density. Likewise, modelling of the boat and crew produced simulations that predicted realistic crew response to tested variables. Unfortunately, the observed lack of adherence to the SLSA footstrap Standard has impeded successful epidemiological and modelling outcomes. If uniformity of boat setup can be assured then epidemiological studies will be able to highlight the influence of implementing changes to the boat design.
In conclusion, the research provided a tool to successfully link the epidemiology and injury diagnosis to the mechanical engineering design through the use of biomechanics. This was a novel application of the mathematical modelling software MADYMO. Other craft can also be investigated in this manner to provide solutions to the problem identified and therefore reduce risk of injury for the operators.
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Tognella, Frederic. "Développement de méthodes pour la quantification de l'évolution des propriétés mécaniques des muscles humains en microgravité." Compiègne, 1994. http://www.theses.fr/1994COMPD679.
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L'atrophie fonctionnelle des muscles humains lors des séjours en microgravité, pose le double problème de sa compréhension, de sa prévention. Les muscles des membres inferieurs, surtout sur le triceps sural, du fait de sa fonction posturale, sont atteints. Les contre-mesures actuelles ne se sont pas pleinement efficaces. Les connaissances les plus précises sont acquises sur le rat ou l'on constate que l'atrophie, s'accompagne de modifications des propriétés contractiles et viscoélastiques. On se propose donc de mettre en place des protocoles non-invasifs d'étude sur les muscles de la cheville humaine, permettant de cerner, au travers de l'évolution des propriétés mécaniques des muscles, la cinétique d'installation de l'atrophie et sa caractérisation. La mise en œuvre des méthodes nécessite la conception d'un dispositif ergométrique motorisé, la mise en place de protocoles expérimentaux, une étude de sécurité, une chaine d'acquisition et de stockage des signaux mécaniques et signaux électromyographiques de surface, et une chaine de traitement des résultats. Ces différentes étapes ont été réalisées dans le cadre de ce travail. Apres une étape de validation, les protocoles ont été appliqués sur une population de trente sujets sportifs et sédentaires dans le but d'établir la validité des résultats, la fiabilité matérielle, la reproductibilité et la sensibilité des données acquises. Cette étape d'évaluation critique, sur la première campagne d'acquisition et de traitement de résultats, a permis de cerner les sources de variabilité des résultats, d'affiner les protocoles, et de formaliser les besoins d'une évolution future du prototype. Les propriétés contractiles sont investiguées par des mouvements de flexion plantaire accomplis dans des conditions d'isocinétisme du mouvement et les résultats sont représentés au mieux par un ajustement exponentiel des données. Les propriétés visco-élastiques sont explorées par l'épreuve de quick release, permettant la quantification de l'évolution d'un index de raideur en fonction du couple statique exerce. Des épreuves de perturbations sinusoïdales de 1, 5 explorent la réponse en fréquence de l'articulation de la cheville, entre 4 et 18 hertz. Un modèle quasi linéaire du second ordre est adéquat pour représenter la fonction de transfert de l'articulation et définir l'impédance mécanique de l'articulation. Finalement, le couplage d'études est abordé, et les perspectives d'utilisation du prototype industriel dans d'autres domaines que celui de la recherche spatiale sont évoquées.
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Wang, Jing. "Measurement of the mechanical properties of angle ply laminates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/NQ53664.pdf.
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Bawcombe, Jonathan. "A study of Douglas-fir anatomical and mechanical properties and their interactions." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558893.
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Low embodied energy, ability to act as a carbon store and ease of recycling gives forest products an important role within a low carbon built environment. Almost 25 % of the coniferous resource within the South West of England is Douglas-fir, a species reputed for producing high quality timber. Despite this, the region is facing challenges in delivering the resources full potential, a contributing factor to which is a loss of knowledge regarding its quality. The aim of the work presented is to gain an improved understanding of the quality of Douglas-fir grown within the region, from the perspective of uses in structural applications, the factors which influence material quality and their interrelationships. Flexural modulus of elasticity, flexural and compressive strength were determined utilising small clear specimens derived from 1.3 and 8 m heights within 27 trees from six sites across the South West. Results showed a rise in the magnitude of properties with increasing cambial age, particularly so at younger ages. Differences in values were also recorded between stem heights and with rate of growth. These were however less than age related variations. Results compared favourably to those reported in other studies conducted on the species. Utilising SilviScan-3, anatomical properties including density, microfibril angle and cellular dimensions were measured. Significant variations were recorded with cambial age, and in some instances sampling height. The influence of growth rate on anatomical properties was small. Through statistical and composite modelling, microfibril angle was found to be strongly associated with changes in modulus of elasticity within juvenile wood. Within mature wood and for strength properties, density was the controlling factor. It was shown that a moderate proportion of variations in mechanical properties can be accounted for utilising visually identifiable wood characteristics. The new understanding that has been gained through this work presents opportunities for improved utilisation, the implementation of effective management practices and the development of more efficient visual grading techniques.
Books on the topic "Ankle – Mechanical properties"
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Robert, Donatelli, ed. The Biomechanics of the foot and ankle. Philadelphia: F.A. Davis Co., 1990.
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Robert, Donatelli, ed. The Biomechanics of the foot and ankle. 2nd ed. Philadelphia: Davis, 1996.
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Foot and ankle pain. 3rd ed. Philadelphia: Davis, 1997.
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Verrill, S. P. JMFA--a graphically interactive java program that fits microfibril angle x-ray diffraction data. Madison, WI: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2001.
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Verrill, S. P. JMFA--a graphically interactive java program that fits microfibril angle x-ray diffraction data. Madison, WI: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2001.
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Verrill, S. P. JMFA 2--a graphically interactive Java program that fits microfibril angle x-ray diffraction data. Madison, WI: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2006.
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Verrill, S. P. JMFA 2--a graphically interactive Java program that fits microfibril angle x-ray diffraction data. Madison, WI: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2006.
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Pechthalt, Tony. Comparison of three methods of ankle stabilization. 1993.
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Robert, Donatelli, ed. The biomechanics of the foot and ankle. 2nd ed. Philadelphia: F.A. Davis, 1995.
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Wang, Jing. Measurement of the mechanical properties of angle ply laminates. 2000.
Find full textBook chapters on the topic "Ankle – Mechanical properties"
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Wang, Yi-Ta, and Yi-Ting Yeh. "Effect of Print Angle on Mechanical Properties of FDM 3D Structures Printed with POM Material." In Lecture Notes in Mechanical Engineering, 157–67. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1771-1_20.
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Kuetemeier, Dennis, and Amsini Sadiki. "Modeling and Simulation of a Turbulent Multi-component Two-phase Flow Involving Phase Change Processes Under Supercritical Conditions." In Fluid Mechanics and Its Applications, 189–209. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09008-0_10.
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AbstractThe present paper aims at developing a generally valid, consistent numerical description of a turbulent multi-component two-phase flow that experiences processes that may occur under both subcritical and trans-critical or supercritical operating conditions. Within an appropriate LES methodology, focus is put on an Euler-Eulerian method that includes multi-component mixture properties along with phase change process. Thereby, the two-phase flow fluid is considered as multi-component mixtures in which the real fluid properties are accounted for by a composite Peng-Robinson (PR) equation of state (EoS), so that each phase is governed by its own PR EoS. The suggested numerical modelling approach is validated while simulating the disintegration of an elliptic jet of supercritical fluoroketone injected into a helium environment. Qualitative and quantitative analyses are carried out. The results show significant coupled effect of the turbulence and the thermodynamic on the jet disintegration along with the mixing processes. Especially, comparisons between the numerical predictions and available experimental data provided in terms of penetration length, fluoroketone density, and jet spreading angle outline good agreements that attest the performance of the proposed model at elevated pressures and temperatures. Further aspects of transcritical jet flow case as well as comparison with an Eulerian-Lagrangian approach which is extended to integrate the arising effects of vanishing surface tension in evolving sprays are left for future work.
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Kumar, Gaurav, Varun Sharma, Rakesh Kumar, Ankit Thakur, Navdeep Minhas, and Om Prakash Verma. "Effect of Tool Tilt Angle on the Mechanical and Metallurgical Properties of Aluminium Alloy 6061-T6 Welded by Friction Stir Welding Process." In Lecture Notes in Mechanical Engineering, 221–29. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-9236-9_20.
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Banga, Harish Kumar, Parveen Kalra, R. M. Belokar, and Rajesh Kumar. "Additively Manufactured Orthotics." In Additive Manufacturing in Biomedical Applications, 434–39. ASM International, 2022. http://dx.doi.org/10.31399/asm.hb.v23a.a0006897.
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Abstract An ankle-foot orthosis (AFO) is a support designed to regulate the ankle's position and mobility, compensate for weakness, or rectify abnormalities. This article focuses on the biomechanical affects and mechanical properties of custom-made 3D-printed AFOs and compares them to traditionally created AFOs. Investigations in the fields of 3D scanning, 3D printing, and computer-aided design and analysis for the production of custom-made AFOs are also covered.
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Meselhy, Adil Abd Elsamia. "Raising the Efficiency of Seohen's Model to Predict Soil Resistance Faced by Chisel Plow." In Precision Agriculture Technologies for Food Security and Sustainability, 257–73. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-5000-7.ch011.
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This research was carried out to study the effect of crop factor, which is represented in some plant roots of crops residues (broad bean and wheat) on soil mechanical properties (cohesion strength, C, and internal friction angle, Φ), and thus, the effect of these roots on the power requirements of chisel plow to face the soil resistance was studied. Soil mechanical properties and power requirements of chisel plow (7 blades) were measured in the field directly at various soil depths of (0.05, 0.1, 0.15, and 0.2 m) with and without roots at constant tractor forward speed of about 4 km/h. Moisture content of the soil, broad bean roots, and wheat roots were 21%, 16%, and 14%, respectively, The results showed that the effect of roots of previous crops residues had a significant effect on the soil mechanical properties and power requirements for chisel plow when using the crop factor, which is represented in characteristic of crop residual roots in terms of root mean diameter.
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Saddem, Mourad, Ahmed Koubaa, and Bernard Riedl. "Properties of High-Density Polyethylene-Polypropylene Wood Composites." In Biocomposites. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101282.
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We investigated the effects of polymer blend variation on the physical, mechanical, and thermal properties of wood-polymer composites (WPC). We used high-density polyethylene (HDPE) and polypropylene (PP) and a combination of 80% PP, 20% HDPE, and 80% HDPE, 20% PP as polymer blends for WPC formulations to simulate recycled plastics. We used black spruce (Picea mariana Mill.) hammer milled fibers (75–250 μm) at 35 wt% as a filler for all the formulations. A two-step process was used for WPC manufacturing; pellet extrusion followed by test samples injection. Tensile and three bending tests characterized the WPC mechanical properties. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) characterized the WPCs’ thermal properties. Water absorption and contact angle measurements assessed the composite dimensional stability. Infrared spectroscopy (FTIR) and electron scanning microscopy (SEM) investigated the WPCs’ surface chemistry and microstructure. Mechanical properties and dimensional stability varied according to polymer composition, with better performance for WPC containing higher PP proportions. Thermal properties varied with the polymer composition in the WPC, with better thermal stability for the formulation containing higher HDPE proportions. Surface chemistry analysis did not reveal any chemical changes on the WPCs surface. Scanning electron microscopy analysis revealed distinct phases in all WPCs without evidence of interfacial adhesion.
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Manjunath Naik, Gajanan, Sachin Bandadka, Manjaiah Mallaiah, Ravindra Ishwar Badiger, and Narendranath Sannayellappa. "Effect of ECAE Die Angle on Microstructure Mechanical Properties and Corrosion Behavior of AZ80/91 Magnesium Alloys." In Magnesium Alloys [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94150.
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Magnesium alloys have poor tensile strength, ductility and corrosion resistance properties associated with other engineering materials like aluminum alloys, steels and superalloys etc. Therefore, many researchers worked on equal channel angular pressing of magnesium alloys to improve the mechanical properties and corrosion resistance. In this work, the effect of channel angles on material properties was investigated during equal channel angular pressing of AZ80/91 magnesium alloy using processing route-R at 598 K processing temperature. Channel angles of 900 and 1100, common corner angle of 300 have been considered for the study. It has been revealed that the channel angle has a significant influence on deformation homogeneity, microhardness, ultimate tensile strength, ductility, and corrosion behavior of AZ80/91 magnesium alloys. Specifically, AZ80/91 Mg alloys processed through 900 channel angle i.e. die A is considered as optimal die parameter to improve above-said material properties. Investigation showing concerning as-received AZ80 and AZ91 Mg alloy indicates 11%, 14% improvement of UTS and 69%, 59% enhancement in ductility after processing through 4P through die A (90°) at 598 K respectively. Also, the corrosion rate reduces to 97% and 99% after processing the sample with 4P-ECAP die A (90°) at the same processing temperature for AZ80 and AZ91 Mg alloys respectively. This is mainly due to grain refinement and distribution of Mg17Al12 secondary phase during ECAP.
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Sambasiva Rao, Mukkollu, and Amitesh Kumar. "Slope Casting Process: A Review." In Casting Processes [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102742.
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Semi solid processing is a near net shape casting process and one of the promising techniques to obtain dendritic free structure of metals. Semi solid casting gives numerous advantages than solid processing and liquid processing. Semi solid casting process gives, Laminar flow filling of die without turbulence, Lower metal temperature, Less shrinkage, Less porosity, Higher mechanical properties. Semi solid casting process is industrially successful, producing a variety of products with good quality. Slope Casting process is a simple technique to produce semi solid feed-stoke with globular microstructure and dendrite free structure castings. Slope casting process depends on different process parameters like slope length, slope angle, pouring temperature etc. The present study mainly focuses on review of various explorations made by researchers with different process parameters of the Slope casting process and explain the mechanisms that lead to microstructural changes which leads to good mechanical properties.
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Thilagham, K. T., and S. Muthukumaran. "Center Stir Zone Investigations of Dissimilar AA6082, AA2014 and AA7075 Welds." In Welding Principles and Application [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102652.
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The study compares the mechanical and metallurgical properties of AA6082, AA2014, and AA7075 dissimilar friction stir welded aluminum 6 mm plates. The alloys AA2014 and AA7075 are aerospace grade, whereas AA6082 is structural grade. The AA6082/AA7075, AA6082/AA2014, and AA2014/AA7075 joints were formed with optimized parameters of 2° tilt angle, 900 rpm rotational speed, and 80 mm/min feed rate with a constant axial force of 20 kN. Then, to investigate the stir zone properties of the joints, the tensile strength, microstructural, and hardness variations across the weld were revealed. Despite the fact that the strength of each joint was varied, the fine grain in the stir zone across the weld and advancing side weld/HAZ failure in tensile failure were studied for all welds. Further EBSD analysis revealed fine grains for the formation of its center stir zone due to dynamic recovery recrystallization during welding.
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Han, Chang Dae. "Rheology of Block Copolymers." In Rheology and Processing of Polymeric Materials: Volume 1: Polymer Rheology. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195187823.003.0014.
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Block copolymer consists of two or more long blocks with dissimilar chemical structures which are chemically connected. There are different architectures of block copolymers, namely, AB-type diblock, ABA-type triblock, ABC-type triblock, and AmBn radial or star-shaped block copolymers, as shown schematically in Figure 8.1. The majority of block copolymers has long been synthesized by sequential anionic polymerization, which gives rise to narrow molecular weight distribution, although other synthesis methods (e.g., cationic polymerization, atom transfer radical polymerization) have also been developed in the more recent past. Owing to immiscibility between the constituent blocks, block copolymers above a certain threshold molecular weight form microdomains (10–50 nm in size), the structure of which depends primarily on block composition (or block length ratio). The presence of microdomains confers unique mechanical properties to block copolymers. There are many papers that have dealt with the synthesis and physical/mechanical properties of block copolymers, too many to cite them all here. There are monographs describing the synthesis and physical properties of block copolymers (Aggarwal 1970; Burke and Weiss 1973; Hamley 1998; Holden et al. 1996; Hsieh and Quirk 1996; Noshay and McGrath 1977). Figure 8.2 shows schematically four types of equilibrium microdomain structures observed in block copolymers. Referring to Figure 8.2, it is well established (Helfand and Wasserman 1982; Leibler 1980) that in microphase-separated block copolymers, spherical microdomains are observed when the volume fraction f of one of the blocks is less than approximately 0.15, hexagonally packed cylindrical microdomains are observed when the value of f is between approximately 0.15 and 0.44, and lamellar microdomains are observed when the value of f is between approximately 0.44 and 0.50. Some investigators have observed ordered bicontinuous double-diamonds (OBDD) (Thomas et al. 1986; Hasegawa et al. 1987) or bicontinuous gyroids (Hajduk et al. 1994) at a very narrow range of f (say, between approximately 0.35 and 0.40) for certain block copolymers. Figure 8.2 shows only one half of the symmetricity about f = 0.5. Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) have long been used to investigate the types of microdomain structures in block copolymers.
Conference papers on the topic "Ankle – Mechanical properties"
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Ho, Patrick, Hyunglae Lee, Mohammad A. Rastgaar, Hermano Igo Krebs, and Neville Hogan. "Interpretation of the Directional Properties of Voluntarily Modulated Human Ankle Mechanical Impedance." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4274.
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This article presents the results of two in-vivo studies providing measurements of human static ankle mechanical impedance. Accurate measurements of ankle impedance when muscles were voluntarily activated were obtained using a therapeutic robot, Anklebot, and an electromyographic recording system. Important features of ankle impedance, and their variation with muscle activity, are discussed, including magnitude, symmetry and directions of minimum and maximum impedance. Voluntary muscle activation has a significant impact on ankle impedance, increasing it by up to a factor of three in our experiments. Furthermore, significant asymmetries and deviations from a linear two-spring model are present in many subjects, indicating that ankle impedance has a complex and individually idiosyncratic structure. We propose the use of Fourier series as a general representation, providing both insight and a precise quantitative characterization of human static ankle impedance.
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Tuanjit Na Rungsri and Jirut Meesane. "Hybrid composite material of bombyx silk fiber for Ankle Foot Orthoses: Morphology, physical, and mechanical properties." In 2012 5th Biomedical Engineering International Conference (BMEiCON). IEEE, 2012. http://dx.doi.org/10.1109/bmeicon.2012.6465469.
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Zhou, Qing, Hailing Yu, Marisol B. Medri, and Frank DiMasi. "Finite Element Model of THOR Dummy Lower Leg." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-39171.
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THOR is a next generation crash test dummy incorporating additional advanced instrumentation and improved biofidelity than the Hybrid III dummy. This paper describes the development and validation of a finite element model of the lower leg assembly of the THOR 50th percentile male. The lower leg assembly has one translational degree-of-freedom in the axial direction along the tibia, and three rotational degrees-of-freedom in the ankle area with respect to its knee joint. It also includes a representation of the Achilles tendon load path. Modeling approaches used to simulate these features are discussed. Material properties of individual deformable components and articulated joints, as well as overall dynamic model performance, are calibrated using results of physical tests that mimic the loading environments experienced by the lower leg and foot in typical vehicle crashes. The model provides a computational tool for studying lower extremity injuries, including that of foot and ankle, which have gained increasing attention in recent years.
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Salman, Muhammad, and M. Hassan Tanveer. "Modeling and Simulation of Achilles Tendon in OpenSim for Verification." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71984.
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Abstract The Achilles tendon is a very important tendon that is vital to an individual’s movement. Once these tendons are torn, they become very difficult to heal. In order to avoid this situation, it is crucial to understand the limitations of the Achilles tendon on the average person. To study the properties of an Achilles tendon, research can be done in many ways, such as data collection of in-vivo specimens. Although this can be done, using an online simulation can result in quicker and more accurate data. One program that can be used to create a simulation of an Achilles tendon is OpenSim. In this study 5 different subjects, both male and female with ages 22+/−5 years are studied. The subject will stand on one foot which is the maximum amount of weight on one leg and that Achilles Tendon. The forces will be calculated on that foot using sensors such as laser displacement sensors. The weight of the subject will cause the ground reaction and the magnitude of the tensile force which will be exerted by the gastrocnemius and soleus muscles on the calcaneus through the Achilles tendon will be calculated. The magnitude of the reaction force of the subject will be exerted at the ankle joint and it is applied by the tibia on the talus dome. The Achilles tendon is attached to the calcaneus bone and for this position of the foot, it is estimated that the line of action of the tensile force in the Achilles tendon makes an angle q (theta) with the horizontal, and the line of action of the ankle joint reaction force makes an angle b (beta) with the horizontal. We will use the force vectors to draw the concurrent diagram in order to find the unknown forces of the Achilles tendon and the tibia reactive force on the joint. By studying the properties of the Achilles tendon, while it is at 2 different dorsiflexed angles. These angles will vary from 0 degrees to 90 degrees. These concurrent force vector diagrams method will be applied to both configurations to find the unknown forces of the Achilles tendon and the tibia reaction on the dome of the talus. OpenSim is mainly used for biomechanical modeling and analysis of those models. The purpose of this research paper is to provide a comparison of data collected from real individuals and the simulation data from an OpenSim model.
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PARK, YUJIN, YINGJUN ZHAO DUBUC, AMY SLIDER, PINATA H. . SESSOMS, JOHN J. FRASER, and KENNETH J. LOH. "VARIABLE STIFFNESS HONEYCOMB METAMATERIALS FOR ADAPTIVE ANKLE BRACE DESIGN." In Structural Health Monitoring 2021. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/shm2021/36268.
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Lateral ankle sprains cost billions of dollars in medical expenses annually and frequently result in long-term functional decline and a diminished health-related quality of life. While ankle braces have been shown to be effective in prophylaxis of subsequent ankle sprains, current braces are either too stiff and affect normal gait or too flexible and provide insufficient support during high-intensity activities. In this study, we proposed an adaptive ankle brace design that employs dynamically variable stiffness components to provide minimum support under normal gait movements and maximum rigidity under large ranges of motion. To achieve these unique properties, a honeycomb geometry was designed and three dimensionally printed with thermoplastic polyurethane to exhibit nonlinear, strain-stiffening, elastic behavior. We conducted a series of tensile load tests on different honeycomb unit cell configurations. First, the influence of unit cell designs on their mechanical strength and force-strain profiles was characterized. Second, experimentally calibrated finite element models of individual components simulated the mechanical response of the geometry, which were then used to optimize the geometrical parameters of the honeycomb shape (i.e., ring size, length of lateral elements, and thickness). The results identified promising design parameters for these honeycomb geometries that could be used to realize next-generation adaptive ankle braces.
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Hollander, Kevin W., Thomas G. Sugar, and Donald E. Herring. "A Robotic “Jack Spring”™ for Ankle Gait Assistance." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84492.
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A Robotic ‘Jack Spring’™ is a new type of mechanical actuator, which is based upon the concept of structure control. A Jack Spring™ mechanism is used to create an adjustable Robotic Tendon, which is a spring based linear actuator in which the properties of a spring are crucial to its successful use in gait assistance. Like its human analog, the adjustable Robotic Tendon uses its inherent elastic nature to reduce both peak power and energy requirements for its motor. In the ideal example, peak power required of the motor for ankle gait is reduced from 250W to just 81 W. In addition, ideal energy requirements are reduced from nearly 36 Joules to just 25 Joules per step. Using this approach, an initial prototype is expected to provide 100% of the power and energy neccessary for ankle gait in a compact 0.84kg package. This weight is 8 times less than that predicted for an equivalent direct drive approach.
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Su, Yilin, Xuyan Hou, Pingping Xue, Kailiang Zhang, Long Li, and Tao Chen. "Adhesion Mechanism of Space Climbing Robot Feet With Microarray Structure for On-Orbit Servicing." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65816.
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For the on-orbit servicing missions of spacecraft, space robot is considered as one of the most promising approaches. Many on-orbit servicing missions are successfully accomplished and most of these missions are designed to service cooperative targets only. Some of the target is non-cooperative spacecraft with unknown motion and kinematics properties. On-orbit servicing is still a challenging research area. The challenge is to ensure the servicing spacecraft safely and stabilize it for subsequent servicing. In order to expand space robot workspace and its task function, this paper presents a new type of space climbing robot which can be carried on mechanical arm. It can climb onto the target spacecraft for repairing, rescuing and removing orbital debris when the connection is established between the space manipulator and the target spacecraft. This robot mobile system is composed of piezoelectric actuation leg, micro adhesive feet, ejector and manipulator. The robot’s crotch joint and ankle joint both have two degrees of freedom with Roll-Pitch organization. In the environment of zero-gravity the obstacles on the target can be crossed by space climbing robot through wriggle movement and turnover movement. The gripping force of the robot is supplied by the adhesive capacity of the robot feet while robot climb along the surface of target spacecraft with weightlessness. The research of its adhesion mechanism is the basis of robot feet design and motion control. The design of robot feet micro array structure imitates the adhesion mechanism of gecko seta. A contact model between the robot feet and spacecraft surface is proposed. A single seta’s DEM (Discrete Element Method) model is set up by stacking micro particles, on the software platform of EDEM. EDEM is a software for discrete element analysis. The attachment and the detachment process of a single seta in different slope angle and its adhesion properties are simulated by using JKR model which is a classical contact mechanics model. The simulation demonstrate that the single seta’s gripping force with 90 degree slope angle is about 20% of the gripping force with 30 degree slope angle. The fiber structure was destroyed by large pressure making failure to its adhesion properties when the slope angle is zero. So the different ways of movement can achieve different adhesion properties of single seta. When the movement of micro array structure is determined, in order to improve the robust adhesion properties, well stability and excellent adaptability of the micro array structure, the structure parameters of seta is optimized. The structure parameters include the cylinder radius, length-diameter ratio and arrangement density of the micro array structure. A group of micro array structure optimized parameters is given according to the DEM comparing simulations with different structure parameters. This work propose a novel adhesion concept for climbing robot in space environment, and the stable attaching and easy detaching mechanism of the robot is also given.
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Durfee, William, Saeed Hashemi, and Andrew Ries. "Hydraulic Ankle Foot Orthosis Emulator for Children With Cerebral Palsy." In BATH/ASME 2020 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fpmc2020-2791.
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Abstract Objective: Ankle foot orthoses (AFOs) are used by nearly 50% of children with cerebral palsy (CP) to ameliorate gait impairments. The methods used to prescribe and tune the mechanical properties of an AFO, including its angular stiffness about the ankle, are based on the intuition and experience of the practitioner. The long-term goal of this research is to develop and deploy a technology-based solution to prescribing passive AFOs that uses an AFO emulator to be used in the clinic that can, under computer control, vary its stiffness in real-time to determine the best stiffness for walking. The objective of this project was to design and bench-test a first-generation wearable hydraulic ankle exoskeleton, and to conduct a small clinical trial to determine whether walking in a conventional plastic AFO was the same as walking in the hydraulic exoskeleton whose stiffness was programmed to match that of the conventional AFO. Methods: The hydraulic ankle exoskeleton was comprised of a wearable ankle exoskeleton tethered by small-diameter hydraulic hose to a push-behind cart that contained the hydraulic power supply and control components. The ankle component contained a novel double-ended cylinder with a cable anchored to the piston. The system was controlled to emulate a rotary spring. Bench top tests were performed to validate the performance of the system. In addition, an early feasibility clinical trial was conducted with five children with cerebral palsy who walked in three conventional AFOs (flexible, medium and stiff) and the hydraulic AFO controlled to match each stiffness. Kinematics and dynamics of gait were measured with a 12-camera motion capture system and a force plate. Results: The weight of the wearable exoskeleton plus shoe was 1.5 kg, 60% over the design goal. The system, running at a rail pressure of 141 bar (2,050 psi), could produce 62 Nm of torque and could emulate springs from 1 to 4.6 Nm/deg, the stiffness range of most conventional AFOs. Once calibrated, the torque-displacement properties were similar to the matched conventional AFO. Walking metrics were the same for hydraulic and conventional AFOs. Interpretation: Small-scale hydraulics are effective for a wearable exoskeleton that is designed to mimic a passive AFO and hydraulics can be used to emulate a rotary stiffness. While heavier than the design target, the added weight of the hydraulic system did not seem to impact walking in a significant way. The metrics used to evaluate walking were not sensitive enough to detect any subtle differences between walking with the hydraulic system and walking in a normal AFO.
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Adamczyk, Peter G., Michelle Roland, and Michael E. Hahn. "Parametric Evaluation of Hindfoot and Forefoot Properties and Their Effect on the Angular Stiffness of Prosthetic Feet." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80839.
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Prosthetic foot stiffness has been recognized as an important factor in optimizing the walking performance of amputees [1–3]. Commercial feet are available in a range of stiffness categories and geometries. The stiffness of linear displacements of the hindfoot and forefoot for several commercially available feet have been reported to be within a range of 27–68 N/mm [4] and 28–76 N/mm [5], respectively, but these values are most relevant only to the earliest and latest portions of stance phase, when linear compression or rebound naturally occur. In contrast, mid-stance kinetics are more related to the angular stiffness of the foot, which describes the ankle torque produced by angular progression of the lower limb over the foot during this phase. Little data is available regarding the angular stiffness of any commercially available feet. The variety of geometries between manufacturers and models of prosthetic feet makes a direct calculation of effective angular stiffness challenging due to changes in moment arms based on loading condition, intricacies of deformation mechanics of the structural components, and mechanical interaction between hindfoot and forefoot components. Thus, modeling the interaction between hindfoot stiffness, forefoot stiffness, and keel geometries and their combined effect on the angular stiffness of the foot may be a useful tool for correlating functional outcomes with stiffness characteristics of various feet. To understand how each of these factors affects angular stiffness, we developed a foot that can parametrically adjust each of these factors independently. The objective of this study was to mathematically model, design, and experimentally validate a prosthetic foot that has independent hindfoot and forefoot components, allowing for parametric adjustment of stiffness characteristics and keel geometry in future studies of amputee gait.
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Fielding, Rebecca A., Reuben H. Kraft, X. G. Tan, Andrzej J. Przekwas, and Christopher D. Kozuch. "High Rate Impact to the Human Calcaneus: A Micromechanical Analysis." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38930.
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An “underbody blast” (UBB) is the detonation of a mine or improvised explosive device (IED) underneath a vehicle. In recent military conflicts, the incidence of UBBs has led to severe injuries, specifically in the lower extremities The foot and ankle complex, particularly the calcaneus bone, may sustain significant damage. Despite the prevalence of calcaneal injuries, this bone’s unique properties and the progression of fracture and failure have not been adequately studied under high strain rate loading. This research discusses early efforts at creating a high-resolution computational model of the human calcaneus, with primary focus on modeling the fracture network through the complex microstructure of the bone and creating micromechanically-based constitutive models that can be used within full human body models. The ultimate goal of this ongoing research effort is to develop a micromechanics-based simulation of calcaneus fracture and fragmentation due to impact loading. With the goal of determining the basic mechanisms of stress propagation through the internal structure of the calcaneus, a two-dimensional model was employed for preliminary simulations with a plane-strain approximation. In this effort, a cadaveric calcaneus was scanned to a resolution of 55 μm using an industrial micro-computed tomography (microCT) scanner. A mid-sagittal plane slice of the scan was selected and post-processed to generate a 2D finite element mesh of the calcaneus that included marrow, trabecular bone, and cortical bone elements. The calcaneus was modeled using two-dimensional quadratic plane strain elements. A fixed boundary condition was applied to the portion of the calcaneus that, in situ, would be restrained by the talus. A displacement of 1.25 mm was applied to the heel of the calcaneus over 5 ms. In a typical result, following impact, the strain and stress are propagated throughout the cortical shell and then began to radiate into the bone into the bone along the trabeculae. Local stress concentrations can be observed in the trabecular structure in the posterior region of the bone following impact. Upon impact, cortical and trabecular bone show different stresses of 13MPa and 1 MPa, respectively, and exhibit complex high frequency responses. Observed results may offer insight into the wave interactions between the different materials comprising the calcaneus, such as impedance mismatch and refraction. Pore pressure in the marrow may be another important factor to consider in understanding stress propagation in the calcaneus.
Reports on the topic "Ankle – Mechanical properties"
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Comparison of mechanical behavior between longitudinal lap-welded joints and transverse fillet welded joints of high strength steel. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.302.
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Mechanical behavior of twenty-eight longitudinal lap-welded joints made of high strength steels (HSS) under tension load was investigated by experimental study. Weaknesses due to traditional deformation measurements for fillet welded joints can be perfectly solved by digital image correlation techniques (DIC). The effect of parameters (e.g. weld size, weld length and mismatch ratio) on mechanical properties (e.g. ultimate strength, failure modes, weld ductility and fracture angle) of longitudinal fillet welds and transverse fillet welds, which was introduced in detail in previous work by the authors, were compared. Generally, because of the difference on the combination of shear force and tension force, the fracture angle of longitudinal welded specimens (around 50) were much more divergent from transverse welded specimens (around 20) even though both of them failed at welded zone (welded zone only refers to weld metal in this paper), resulting that the mean strength of longitudinal welded specimens were only 0.58 time of transverse welded specimens. Conversely, the mean deformation capacity of longitudinal welded specimens was almost 4.0 times of transverse welded specimens. Moreover, it was confirmed that the predicted loads of EC3 and AISC Specification were close and slightly conservative for all specimens.