Custom foot orthoses (CFOs) are effective in the prevention and treatment of lower extremity injuries (LEIs). However, the current design methodologies of CFOs are not efficient due to the limited consideration of soft tissue impedance, orthotic properties and subjective feedback during the measurement. A new design methodology of CFOs is required to determine the desired orthotic properties including geometry and impedance, which satisfy pressure/load distribution, subjective comfort and reduce iterations. A measurement device which provides an Interface with Tunable Ergonomic properties using a Reconfigurable Framework with Adjustable Compliant Elements (INTERFACE) is developed. The INTERFACE system provides locally adjustable geometry and stiffness for the support of Medial Longitudinal Arch (MLA) by applying a mechanism with six degrees of freedom and three Tunable Stiffness Mechanisms (TSMs). Therefore, the Rapid Evaluate and Adjust Device (READ) Methodology can be implemented by adjusting the interface properties based on the pressure/load and subjective evaluation. The prototype of the INTERFACE system was fabricated to conduct the validation test on 10 subjects, in which the interface pressure/load distribution and subjective feedback in different combinations of geometry and stiffness were recorded. The plantar pressure/load increased with stiffness and geometrical height, and the significance has been demonstrated by a correlation analysis. Subjective comfort can be achieved with different combinations of geometry and stiffness. The proposed INTERFACE system can be employed to conduct the plantar measurement to obtain the desired orthotic properties which satisfy objective and subjective requirements.
{"title":"Design and Development of a Reconfigurable and Adjustable Compliance System for the Measurement of Orthotic Properties","authors":"Yaru Mo, Zeeshan Qaiser, Shane Johnson","doi":"10.1115/imece2021-70326","DOIUrl":"https://doi.org/10.1115/imece2021-70326","url":null,"abstract":"\u0000 Custom foot orthoses (CFOs) are effective in the prevention and treatment of lower extremity injuries (LEIs). However, the current design methodologies of CFOs are not efficient due to the limited consideration of soft tissue impedance, orthotic properties and subjective feedback during the measurement. A new design methodology of CFOs is required to determine the desired orthotic properties including geometry and impedance, which satisfy pressure/load distribution, subjective comfort and reduce iterations. A measurement device which provides an Interface with Tunable Ergonomic properties using a Reconfigurable Framework with Adjustable Compliant Elements (INTERFACE) is developed. The INTERFACE system provides locally adjustable geometry and stiffness for the support of Medial Longitudinal Arch (MLA) by applying a mechanism with six degrees of freedom and three Tunable Stiffness Mechanisms (TSMs). Therefore, the Rapid Evaluate and Adjust Device (READ) Methodology can be implemented by adjusting the interface properties based on the pressure/load and subjective evaluation. The prototype of the INTERFACE system was fabricated to conduct the validation test on 10 subjects, in which the interface pressure/load distribution and subjective feedback in different combinations of geometry and stiffness were recorded. The plantar pressure/load increased with stiffness and geometrical height, and the significance has been demonstrated by a correlation analysis. Subjective comfort can be achieved with different combinations of geometry and stiffness. The proposed INTERFACE system can be employed to conduct the plantar measurement to obtain the desired orthotic properties which satisfy objective and subjective requirements.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115404881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michael Davidson, N. Daher, Thomas Fryer, Johannes Schaepper, D. Tran
We report on our design and initial evaluation of a prototype robotic prosthetic leg (RPL) with a powered non-backdrivable knee and a hydro-pneumatic passive-resistive ankle. Our design was intended to increase health providers’ opportunities when offering their patients greater options, expanding the accessibility of advanced technology to those with lower functional levels of ambulation while decreasing the overall costs of care. The purpose of this biomedical device was to improve stance stability, increase balance confidence, and through powered-knee extension, reduce the contralateral limb’s kinetic stresses in gait, sitting, and standing. This device was designed to provide K2 and above ambulators a more adaptive, safe, and enhanced lower limb prosthesis. The prototype was assessed on a healthy subject while performing multiple 10-meter walk tests (10MWT) and six-minute walk tests (6MWT) on level-ground, inclines, and declines. We report walking velocity, the frequency of steps, cadence, falls, stumbles, toe-drags, battery consumption, and estimated torque of the knee actuator. We found the device safe on an able-bodied subject and feasible for future use on persons with limb loss.
{"title":"Design, Prototyping, and Testing of a Robotic Prosthetic Leg Preliminary Results","authors":"Michael Davidson, N. Daher, Thomas Fryer, Johannes Schaepper, D. Tran","doi":"10.1115/imece2021-68786","DOIUrl":"https://doi.org/10.1115/imece2021-68786","url":null,"abstract":"\u0000 We report on our design and initial evaluation of a prototype robotic prosthetic leg (RPL) with a powered non-backdrivable knee and a hydro-pneumatic passive-resistive ankle. Our design was intended to increase health providers’ opportunities when offering their patients greater options, expanding the accessibility of advanced technology to those with lower functional levels of ambulation while decreasing the overall costs of care. The purpose of this biomedical device was to improve stance stability, increase balance confidence, and through powered-knee extension, reduce the contralateral limb’s kinetic stresses in gait, sitting, and standing. This device was designed to provide K2 and above ambulators a more adaptive, safe, and enhanced lower limb prosthesis. The prototype was assessed on a healthy subject while performing multiple 10-meter walk tests (10MWT) and six-minute walk tests (6MWT) on level-ground, inclines, and declines. We report walking velocity, the frequency of steps, cadence, falls, stumbles, toe-drags, battery consumption, and estimated torque of the knee actuator. We found the device safe on an able-bodied subject and feasible for future use on persons with limb loss.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116355785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sport climbing performance analysis requires knowledge of the specific motions and the interactions of the athlete with the climbing holds. The objective of this research is to develop a low-cost measurement system for detecting performance parameters with an instrument mounting screw used with a climbing hold. In the preliminary study, strain gauges were bonded to the shank of a screw and analyzed according to bending theory. For the experimental results, a climbing hold was mounted to a provisional wall with an instrumented mounting screw. The system was able to detect loads at increments of 2 kg applied to the climbing hold with accuracy and repeatability. Testing of loading when applied laterally from the center of the climbing hold showed that the alignment of the strain gauge and location of applied loads are important. The measurement system was capable of identifying the total contact time and time for each application of loads more than 1 kg. Results showed an instrumented mounting screw can be used for monitoring the climber’s fluency during climbing and provide information about load distribution between climbing holds during their ascent.
{"title":"Preliminary Study: Development of Sport Climbing Hold Measurement System for Performance Analysis","authors":"Nina Pernuš, D. Munro","doi":"10.1115/imece2021-67624","DOIUrl":"https://doi.org/10.1115/imece2021-67624","url":null,"abstract":"\u0000 Sport climbing performance analysis requires knowledge of the specific motions and the interactions of the athlete with the climbing holds. The objective of this research is to develop a low-cost measurement system for detecting performance parameters with an instrument mounting screw used with a climbing hold. In the preliminary study, strain gauges were bonded to the shank of a screw and analyzed according to bending theory. For the experimental results, a climbing hold was mounted to a provisional wall with an instrumented mounting screw. The system was able to detect loads at increments of 2 kg applied to the climbing hold with accuracy and repeatability. Testing of loading when applied laterally from the center of the climbing hold showed that the alignment of the strain gauge and location of applied loads are important. The measurement system was capable of identifying the total contact time and time for each application of loads more than 1 kg. Results showed an instrumented mounting screw can be used for monitoring the climber’s fluency during climbing and provide information about load distribution between climbing holds during their ascent.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131684114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work is centered on high-fidelity modeling, analysis, and rigorous experiments of vibrations and guided (Lamb) waves in a human skull in two connected tracks: (1) layered modeling of the cranial bone structure (with cortical tables and diploë) and its vibration-based elastic parameter identification (and validation); (2) transcranial leaky Lamb wave characterization experiments and radiation analyses using the identified elastic parameters in a layered semi analytical finite element framework, followed by time transient simulations that consider the inner porosity as is. In the first track, non-contact vibration experiments are conducted to extract the first handful of modal frequencies in the auditory frequency regime, along with the associated damping ratios and mode shapes, of dry cranial bone segments extracted from the parietal and frontal regions of a human skull. Numerical models of the bone segments are built with a novel image reconstruction scheme that employs microcomputed tomographic scans to build a layered bone geometry with separate homogenized domains for the cortical tables and the diploë. These numerical models and the experimental modal frequencies are then used in an iterative parameter identification scheme that yields the cortical and diploic isotropic elastic moduli of each domain, whereas the corresponding densities are estimated using the total experimental mass and layer mass ratios obtained from the scans. With the identified elastic parameters, the average error between experimental and numerical modal frequencies is less than 1.5% and the modal assurance criterion values for most modes are above 0.90. Furthermore, the extracted parameters are in the range of the results reported in the literature. In the second track, the focus is placed on the subject of leaky Lamb waves, which has received growing attention as a promising alternative to conventional ultrasound techniques for transcranial transmission, especially to access the brain periphery. Experiments are conducted on the same cranial bone segment set for leaky Lamb wave excitation and radiation characterization. The degassed skull bone segments are used in submersed experiments with an ultrasonic transducer and needle hydrophone setup for radiation pressure field scanning. Elastic parameters obtained from the first track are used in guided wave dispersion simulations, and the radiation angles are accurately predicted using the aforementioned layered model in the presence of fluid loading. The dominant radiation angles are shown to correspond to guided wave modes with low attenuation and a significant out-of-plane polarization. The experimental radiation spectra are finally compared against those obtained from time transient finite element simulations that leverage geometric models reconstructed from microcomputed tomographic scans.
{"title":"Leveraging Vibrations and Guided Waves in a Human Skull","authors":"E. Kohtanen, M. Mazzotti, M. Ruzzene, A. Erturk","doi":"10.1115/imece2021-71315","DOIUrl":"https://doi.org/10.1115/imece2021-71315","url":null,"abstract":"\u0000 This work is centered on high-fidelity modeling, analysis, and rigorous experiments of vibrations and guided (Lamb) waves in a human skull in two connected tracks: (1) layered modeling of the cranial bone structure (with cortical tables and diploë) and its vibration-based elastic parameter identification (and validation); (2) transcranial leaky Lamb wave characterization experiments and radiation analyses using the identified elastic parameters in a layered semi analytical finite element framework, followed by time transient simulations that consider the inner porosity as is. In the first track, non-contact vibration experiments are conducted to extract the first handful of modal frequencies in the auditory frequency regime, along with the associated damping ratios and mode shapes, of dry cranial bone segments extracted from the parietal and frontal regions of a human skull. Numerical models of the bone segments are built with a novel image reconstruction scheme that employs microcomputed tomographic scans to build a layered bone geometry with separate homogenized domains for the cortical tables and the diploë. These numerical models and the experimental modal frequencies are then used in an iterative parameter identification scheme that yields the cortical and diploic isotropic elastic moduli of each domain, whereas the corresponding densities are estimated using the total experimental mass and layer mass ratios obtained from the scans. With the identified elastic parameters, the average error between experimental and numerical modal frequencies is less than 1.5% and the modal assurance criterion values for most modes are above 0.90. Furthermore, the extracted parameters are in the range of the results reported in the literature. In the second track, the focus is placed on the subject of leaky Lamb waves, which has received growing attention as a promising alternative to conventional ultrasound techniques for transcranial transmission, especially to access the brain periphery. Experiments are conducted on the same cranial bone segment set for leaky Lamb wave excitation and radiation characterization. The degassed skull bone segments are used in submersed experiments with an ultrasonic transducer and needle hydrophone setup for radiation pressure field scanning. Elastic parameters obtained from the first track are used in guided wave dispersion simulations, and the radiation angles are accurately predicted using the aforementioned layered model in the presence of fluid loading. The dominant radiation angles are shown to correspond to guided wave modes with low attenuation and a significant out-of-plane polarization. The experimental radiation spectra are finally compared against those obtained from time transient finite element simulations that leverage geometric models reconstructed from microcomputed tomographic scans.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132569153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Friction-induced stick-slip phenomenon has been reported in 1–20% of patients with ceramic-on-ceramic total hip replacement. The friction behavior of the bearing surfaces is ruled by the lubrication conditions, which may be from hydrodynamic lubrication to mixed or boundary lubrication. In the latter two situations, surface-to-surface mechanical contact may give rise to the friction-induced stick-slip phenomenon. Essentially, stick-slip occurs when the film lubrication is broken. Stick-slip is an undesired phenomenon and is understood to give rise to the squeaking phenomenon in the hip bearing surfaces. In this study, the influence of the relative densities of biofluid, size, mass, and femoral head material is investigated to study the system’s response and the approach of the femoral head towards the acetabulum shell (initial contact to pre-swing phase). Two configurations were developed, which included ball-on-plane and ballon socket configurations. Utilizing parametric studies, the role of these variables was studied. Higher velocity-derived energy may contribute to the vibration of the system via stick-slip. High approach velocity combined with high-density material may influence and lead to surface-surface articulation.
{"title":"A Parametric Study: Influence of Geometry and Material Properties on the Response of the Femoral Head Through Biofluid","authors":"M. Paliwal","doi":"10.1115/imece2021-70061","DOIUrl":"https://doi.org/10.1115/imece2021-70061","url":null,"abstract":"\u0000 Friction-induced stick-slip phenomenon has been reported in 1–20% of patients with ceramic-on-ceramic total hip replacement. The friction behavior of the bearing surfaces is ruled by the lubrication conditions, which may be from hydrodynamic lubrication to mixed or boundary lubrication. In the latter two situations, surface-to-surface mechanical contact may give rise to the friction-induced stick-slip phenomenon. Essentially, stick-slip occurs when the film lubrication is broken. Stick-slip is an undesired phenomenon and is understood to give rise to the squeaking phenomenon in the hip bearing surfaces. In this study, the influence of the relative densities of biofluid, size, mass, and femoral head material is investigated to study the system’s response and the approach of the femoral head towards the acetabulum shell (initial contact to pre-swing phase). Two configurations were developed, which included ball-on-plane and ballon socket configurations. Utilizing parametric studies, the role of these variables was studied. Higher velocity-derived energy may contribute to the vibration of the system via stick-slip. High approach velocity combined with high-density material may influence and lead to surface-surface articulation.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130319431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Load-induced fluid flow in lacunar-canalicular porosity in bone has been suggested to play an essential role in bone adaptation. The applied load causes the fluid inside the lacunar-canalicular system to flow. The osteocytes are believed to sense the shear stress exerted due to the fluid flow and drive new bone formation. The energy dissipated in moving fluid may be considered as a stimulus for bone adaptation. The endocortical bone surfaces are also believed to adapt differently compared to the periosteal surfaces. We investigate such differences and present a finite element poroelasticity-based mathematical model on estimating bone formation rate at mid-diaphysis of a C57BL6 mouse tibia subjected to cantilever loading. A weighted average of dissipation energy in the zone of influence has been considered in accordance with the literature. The model predicts bone formation rate (BFR) at the periosteal surface as well as on the endocortical surface. As desired, the model can differentiate between a continuous cyclic loading and a rest-inserted cyclic loading. The model establishes that the difference in bone formation at the two surfaces, viz. endocortical and periosteal, may be due to the difference in dissipation energy density only, caused by different boundary conditions at the two surfaces.
{"title":"Investigating the Difference in Cortical Bone Adaptation at Endocortical and Periosteal Surfaces by Fluid Flow Analysis","authors":"Sanjay Singh, Satwinder Singh, Jitendra Prasad","doi":"10.1115/imece2021-71220","DOIUrl":"https://doi.org/10.1115/imece2021-71220","url":null,"abstract":"\u0000 Load-induced fluid flow in lacunar-canalicular porosity in bone has been suggested to play an essential role in bone adaptation. The applied load causes the fluid inside the lacunar-canalicular system to flow. The osteocytes are believed to sense the shear stress exerted due to the fluid flow and drive new bone formation. The energy dissipated in moving fluid may be considered as a stimulus for bone adaptation. The endocortical bone surfaces are also believed to adapt differently compared to the periosteal surfaces. We investigate such differences and present a finite element poroelasticity-based mathematical model on estimating bone formation rate at mid-diaphysis of a C57BL6 mouse tibia subjected to cantilever loading. A weighted average of dissipation energy in the zone of influence has been considered in accordance with the literature. The model predicts bone formation rate (BFR) at the periosteal surface as well as on the endocortical surface. As desired, the model can differentiate between a continuous cyclic loading and a rest-inserted cyclic loading. The model establishes that the difference in bone formation at the two surfaces, viz. endocortical and periosteal, may be due to the difference in dissipation energy density only, caused by different boundary conditions at the two surfaces.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130821552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The front matter for this proceedings is available by clicking on the PDF icon.
通过点击PDF图标可获得本次会议的主题。
{"title":"IMECE2021 Front Matter","authors":"","doi":"10.1115/imece2021-fm5","DOIUrl":"https://doi.org/10.1115/imece2021-fm5","url":null,"abstract":"\u0000 The front matter for this proceedings is available by clicking on the PDF icon.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126477848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
James E. Bednar, M. Schwartz, John Woo, D. Dow, G. Ma, Marisha Rawlins, Filip Cuckov
Impaired hand motor function degrades performance of activities of daily living (ADL). Exoskeleton devices can assist hand function for ADL, but the associated cost and complexity limit access for many individuals who would otherwise benefit and impedes development for improved devices. A simpler, but functional, open-source design for a hand assistive exoskeleton might expand accessibility and accelerate development. In this paper, we present an electromechanical prototype of a hand exoskeleton that was designed, implemented, and tested for digit extension and flexing. The design and prototype assisted actuation of an individual finger digit using a sliding spring mechanism. The mechanism is a type of underactuated mechanism that converts one degree of freedom linear motion into rotational motion. The resulting prototype was subjected to motion and force testing, with results supporting certain functional aspects of the system. Further development and testing need to be done for the proposed exoskeleton design, especially as an open-source design. Being open-source would widen access, accelerate development, and improve the quality of life for many individuals.
{"title":"Electro-Mechanical Design Toward an Open-Sourced Robotic Hand Exoskeleton for Management of Neurological and Neurodegenerative Disorders","authors":"James E. Bednar, M. Schwartz, John Woo, D. Dow, G. Ma, Marisha Rawlins, Filip Cuckov","doi":"10.1115/imece2021-73668","DOIUrl":"https://doi.org/10.1115/imece2021-73668","url":null,"abstract":"\u0000 Impaired hand motor function degrades performance of activities of daily living (ADL). Exoskeleton devices can assist hand function for ADL, but the associated cost and complexity limit access for many individuals who would otherwise benefit and impedes development for improved devices. A simpler, but functional, open-source design for a hand assistive exoskeleton might expand accessibility and accelerate development. In this paper, we present an electromechanical prototype of a hand exoskeleton that was designed, implemented, and tested for digit extension and flexing. The design and prototype assisted actuation of an individual finger digit using a sliding spring mechanism. The mechanism is a type of underactuated mechanism that converts one degree of freedom linear motion into rotational motion. The resulting prototype was subjected to motion and force testing, with results supporting certain functional aspects of the system. Further development and testing need to be done for the proposed exoskeleton design, especially as an open-source design. Being open-source would widen access, accelerate development, and improve the quality of life for many individuals.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129417130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Orthopedic implants are widely used for treating bone tumors and trauma defects in patients. The complex and organic geometry of patient-customized implants (PCIs) required in single order quantity makes them suitable for fabrication using additive manufacturing technologies such as Laser beam powder bed fusion. While there is considerable technical literature on these technologies, the choice of optimal process parameters to obtain the required quality considering the relevant applicable international quality standards for orthopedic implants is still a major challenge for the manufacturers. This experimental work relies on the minimum requirements of various mechanical properties recommended by ASTM F3001-14 and ASTM F136-13 standards for determining the optimal process parameters for PCI manufacture. Ti6Al4V ELI (Titanium–6Aluminum–4Vanadium Extra-Low-Interstitial) alloy test samples were fabricated using a Direct Metal Laser Sintering (DMLS) system. The three most critical printing parameters, namely, laser power, laser velocity and hatch distance, were varied in three levels using the Taguchi approach. Properties such as ultimate tensile strength, percentage elongation and part density were considered for optimizing the process parameter combinations using VIKOR, a multi-criteria decision-making technique. The results show that a combination of moderate laser power, high laser velocity and low hatch distance values produce implants with superior mechanical properties. The proposed methodology and results are expected to help researchers and manufacturers in choosing the initial process parameters for PCI fabrication.
{"title":"Additive Manufacturing Process Parameter Optimization for Titanium-Alloy Orthopedic Implants","authors":"B. Gaur, Rupesh Ghyar, B. Ravi","doi":"10.1115/imece2021-70436","DOIUrl":"https://doi.org/10.1115/imece2021-70436","url":null,"abstract":"\u0000 Orthopedic implants are widely used for treating bone tumors and trauma defects in patients. The complex and organic geometry of patient-customized implants (PCIs) required in single order quantity makes them suitable for fabrication using additive manufacturing technologies such as Laser beam powder bed fusion. While there is considerable technical literature on these technologies, the choice of optimal process parameters to obtain the required quality considering the relevant applicable international quality standards for orthopedic implants is still a major challenge for the manufacturers.\u0000 This experimental work relies on the minimum requirements of various mechanical properties recommended by ASTM F3001-14 and ASTM F136-13 standards for determining the optimal process parameters for PCI manufacture. Ti6Al4V ELI (Titanium–6Aluminum–4Vanadium Extra-Low-Interstitial) alloy test samples were fabricated using a Direct Metal Laser Sintering (DMLS) system. The three most critical printing parameters, namely, laser power, laser velocity and hatch distance, were varied in three levels using the Taguchi approach. Properties such as ultimate tensile strength, percentage elongation and part density were considered for optimizing the process parameter combinations using VIKOR, a multi-criteria decision-making technique. The results show that a combination of moderate laser power, high laser velocity and low hatch distance values produce implants with superior mechanical properties. The proposed methodology and results are expected to help researchers and manufacturers in choosing the initial process parameters for PCI fabrication.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115227799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sahil Pitre, Bryan Curtin, P. Pena, Ciaphus Rouse, E. Joseph, Joshua Hooper, A. Tekes
This study presents a passive, self-actuated, 3D printed compliant knee joint for children in developing regions to decrease the overall expense of above knee prosthesis as well as increase the ease to print multiple prosthesis during their growing cycle. A single piece designed five-bar mechanism is proposed to provide adequate human-like gait instead of the traditional pegleg gait provided in previous rigid models. This gait is achieved through the use of both compliant links as well a novel 3D printed approach which is more accustomed to children because of the mechanism’s lightweight. In addition to the compliant knee joint, a compliant ankle possessing a flexure hinge placed at the toe is also designed to provide required bending during the gait cycle. The approach of using a fully passive knee joint enables to limit the weight of the prosthesis to create less of a burden to children and by isolating the need to utilize motors. A test bench consisted of a rack-pinion, two parallel rods, supports, and two servo motors are fabricated to experiment the performance of the knee joint. While the test bench is 3D printed using polylactic acid (PLA), the compliant knee joint is 3D printed in thermoplastic polyurethane (TPU) to emulate the gestures of a real human leg. Simulations are performed in Matlab Simscape to validate that the proposed knee joint mimics the human knee and desired angles.
{"title":"Preliminary Design and Experimental Studies of a Compliant Knee Joint for Pediatric Above Knee Amputees","authors":"Sahil Pitre, Bryan Curtin, P. Pena, Ciaphus Rouse, E. Joseph, Joshua Hooper, A. Tekes","doi":"10.1115/imece2021-73655","DOIUrl":"https://doi.org/10.1115/imece2021-73655","url":null,"abstract":"\u0000 This study presents a passive, self-actuated, 3D printed compliant knee joint for children in developing regions to decrease the overall expense of above knee prosthesis as well as increase the ease to print multiple prosthesis during their growing cycle. A single piece designed five-bar mechanism is proposed to provide adequate human-like gait instead of the traditional pegleg gait provided in previous rigid models. This gait is achieved through the use of both compliant links as well a novel 3D printed approach which is more accustomed to children because of the mechanism’s lightweight. In addition to the compliant knee joint, a compliant ankle possessing a flexure hinge placed at the toe is also designed to provide required bending during the gait cycle. The approach of using a fully passive knee joint enables to limit the weight of the prosthesis to create less of a burden to children and by isolating the need to utilize motors. A test bench consisted of a rack-pinion, two parallel rods, supports, and two servo motors are fabricated to experiment the performance of the knee joint. While the test bench is 3D printed using polylactic acid (PLA), the compliant knee joint is 3D printed in thermoplastic polyurethane (TPU) to emulate the gestures of a real human leg. Simulations are performed in Matlab Simscape to validate that the proposed knee joint mimics the human knee and desired angles.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134325662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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