Armita Hamidi - Academia.edu (original) (raw)

Papers by Armita Hamidi

Smart Materials in Additive Manufacturing, Volume 2 : 4D Printing Mechanics, Modeling, and Advanced Engineering Applications

Smart Materials and Structures, 2020

Materials & Design, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Bio-Design and Manufacturing, 2019

Highly deformable bodies are essential for numerous types of applications in all sorts of environ... more Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many biomimetic structures. Recently, soft robots are favored over rigid structures for their highly compliant material, high-deformation properties at low forces, and ability to operate in difficult environments. However, it is still challenging to fabricate complex designs that satisfy application constraints due to the combined effects of material properties, actuation method, and structural geometry on the performance of the soft robot. Therefore, a combination of a rigid joint and a soft body can help achieve modular robots with fully functional body morphology. Yet, the fabrication of soft parts requires extensive molding for complex shapes, which comprises several processes and can be time-consuming. In addition, molded connections between extremely soft materials and hard materials can be critical failing points. In this paper, we present a functionally graded 3D-printed joint-like structure actuated by novel contractile actuators. Functionally graded materials (FGMs) via 3D printing allow for extensive material property enhancement and control which warrant tunable functionalities of the system. The 3D-printed structure is made of 3 rigid ball and socket joints connected in series and actuated by integrating twisted and coiled polymer fishing line (TCP FL) actuators, which are confined in the FGM accordion-shaped channels. The implementation of the untethered TCP FL actuation system can be highly beneficial for deployment in environments that require low vibrations and silent actuation. The fishing line TCP actuators produce an actuation strain up to 40% and bend the joint up to 40° in any direction. The TCP FL can be actuated individually or as a group to control the bending trajectory of the modular joint, which is beneficial when deployed in areas that contain small crevices. Obtaining complex modes of bending, the FGM multidirectional joint demonstrated a great potential to achieve different functionalities such as crawling, rolling, swimming, or underwater exploration.

Active and Passive Smart Structures and Integrated Systems 2017, 2017

With increasing popularity of portable devices for outdoor activities, portable energy harvesting... more With increasing popularity of portable devices for outdoor activities, portable energy harvesting devices are coming into spot light. The next generation energy harvester which is called hybrid energy harvester can employ more than one mechanism in a single device to optimize portion of the energy that can be harvested from any source of waste energy namely motion, vibration, heat and etc. In spite of few recent attempts for creating hybrid portable devices, the level of output energy still needs to be improved with the intention of employing them in commercial electronic systems or further applications. Moreover, implementing a practical hybrid energy harvester in different application for further investigation is still challenging. This proposal is projected to incorporate a novel approach to maximize and optimize the voltage output of hybrid energy harvesters to achieve a greater conversion efficiency normalized by the total mass of the hybrid device than the simple arithmetic sum of the individual harvesting mechanisms. The energy harvester model previously proposed by Larkin and Tadesse [1] is used as a baseline and a continuous unidirectional rotation is incorporated to maximize and optimize the output. The device harvest mechanical energy from oscillatory motion and convert it to electrical energy through electromagnetic and piezoelectric systems. The new designed mechanism upgrades the device in a way that can harvest energy from both rotational and linear motions by using magnets. Likewise, the piezoelectric section optimized to harvest at least 10% more energy. To the end, the device scaled down for tested with different sources of vibrations in the immediate environment, including machinery operation, bicycle, door motion while opening and closing and finally, human motions. Comparing the results from literature proved that current device has capability to be employed in commercial small electronic devices for enhancement of battery usage or as a backup power source. [1] Larkin, Miles, and Yonas Tadesse. "HM-EH-RT: hybrid multimodal energy harvesting from rotational and translational motions." International Journal of Smart and Nano Materials 4.4 (2013): 257-285.

SPIE Proceedings, 2016

Energy harvesting from structure vibration, human motion or environmental source has been the foc... more Energy harvesting from structure vibration, human motion or environmental source has been the focus of researchers in the past few decades. This paper proposes a novel design that is suitable to harvest energy from human motions such as dancing or physical exercise and use the device to engage young students in Science, Technology, Engineering and Math (STEM) fields and outreach activities. The energy harvester (EH) device was designed for a dominant human operational frequency range of 1–5 Hz and it can be wearable by human. We proposed to incorporate different genres of music coupled with energy harvesting technologies for motivation and energy generation. Students will learn both science and art together, since the energy harvesting requires understanding basic physical phenomena and the art enables various physical movements that imparts the largest motion transfer to the EH device. Therefore, the systems are coupled to each other. Young people follow music updates more than robotics or energy harvesting researches. Most popular videos on YouTube and VEVO are viewed more than 100 million times. Perhaps, integrating the energy harvesting research with music or physical exercise might enhance students’ engagement in science, and needs investigation. A multimodal energy harvester consisting of piezoelectric and electromagnetic subsystems, which can be wearable in the leg, is proposed in this study. Three piezoelectric cantilever beams having permanent magnets at the ends are connected to a base through a slip ring. Stationary electromagnetic coils are installed in the base and connected in series. Whenever the device is driven by any oscillation parallel to the base, the unbalanced rotor will rotate generating energy across the stationary coils in the base. In another case, if the device is driven by an oscillation perpendicular to the base, a stress will be induced within the cantilever beams generating energy across the piezoelectric materials.

Electroactive Polymer Actuators and Devices (EAPAD) XX, 2018

Actuators are the most important elements that affect the performance of biorobotic systems desig... more Actuators are the most important elements that affect the performance of biorobotic systems design and development. One of the objectives of this project is to design stronger, lighter, 3D printable, functionally graded bone-like structures and bio-inspired musculoskeletal system for the articulation of robots. Another objective is to identify the fundamental science of manufacturing and modeling of the muscle systems. A modular building block is presented consisting of bone-like structures, cartilages and artificial muscles (that are inexpensive and powerful), which can be cascaded to create complex robots. In this paper, we present terrestrial robots as a demonstration of the building blocks for biorobotic systems. We particularly illustrate a humanoid robot developed using soft actuators based on twisted and coiled polymer (TCP) muscles. The integration of TCPs in biorobotic systems has some challenges to overcome such as initial pre-stress, adding multiple actuators in parallel or in antagonistic pair and speed of actuation and other accessories. We will quantify the performance of these robots experimentally. We presented two TCP muscles types, one without heating element and the other one that incorporates a heating element that allows electrical actuation.

Smart Materials and Structures, 2020

Jellyfish are energy-efficient swimmers due to the muscle-powered flapping of their soft bell tha... more Jellyfish are energy-efficient swimmers due to the muscle-powered flapping of their soft bell that facilitates a unique energy recapture mechanism. In this paper, we present a bio-inspired jellyfish robot named Poly-Saora that mimics the swimming behavior of the jellyfish species Black sea nettle (Chrysaora achlyos). An assembly-based fabrication method is used to create the Poly-Saora that is developed mainly with polymeric materials (95% of the robot by volume). Twisted and coiled polymer (TCP) actuators are successfully implemented in this robot and show great potential for underwater applications. The influence of different parameters such as the amplitude of the input power, the actuation frequency, and the lifecycle of the actuator are investigated underwater. A full characterization of 6-ply TCP muscles is demonstrated. An actuation strain of ∼10 % is achieved in water at a frequency of 0.1Hz and 50 kPa load. When integrated into the jellyfish, the TCP was able to bend a single bell by 17˚. Poly-Saora was able to swim a vertical distance of 180 mm in 220 s with four TCP actuators each confined in a separate conduit. The robot mimics the swimming behavior of a real jellyfish by contracting the bell segments through the activation of the actuators, which generates forced water circulation under the bell in a pulsating rhythm, consequently creating a vertical movement of the robot. Overall, Poly-Saora is presenting a model of an underwater system that is driven by stimuli-responsive polymer materials and has unique advantages over conventional rigid robots due to their lightweight, muscle-like structures, silent actuation and ease of manufacturing. This robot can be used for safe interaction with other underwater species and their natural habitats when fully developed.

Composite Structures, 2018

Multimaterial additive manufacturing technique is a great alternative approach for fabrication of... more Multimaterial additive manufacturing technique is a great alternative approach for fabrication of complex structures with diverse mechanical properties compared to traditional assembly process. Fused deposition modeling is a simple, popular and affordable technique, which is available in numerous desktop 3D printers nowadays. However, this technology is not developed considerably to co-fabricate highly stretchable (800% strain) elastomer materials with low stiffness and high strength parts in one single build platform. In this paper, a single step fabrication of a novel bioinspired joint system, consisting of dissimilar materials with high strength and high strain elements is developed by an inexpensive 3D printer. The joint consists of continuous metal fibers reinforced thermoplastic part that resembles bones and soft elastomer that mimics soft tissues. Tensile test results of the 3D printed reinforced thermoplastic part showed a 78% increase in strength, which can be competed with natural bone. Highly stretchable elastomer is used for the soft parts that was directly 3D printed and simultaneously cured by heating. Overall, a simple and cost effective heterogeneous material manufacturing technique is developed that maintained high mechanical strength and sufficient elasticity, to produce a bioinspired joint that composed of a rigid skeleton covered by a very soft elastomer.

Desalination, 2015

Prostaglandin F2a (PGF) treatment is routinely used in the reproductive management of mares to in... more Prostaglandin F2a (PGF) treatment is routinely used in the reproductive management of mares to induce luteolysis and allow a subsequent return to estrus. The objective of this retrospective study was to assess the effect of follicle size at the time of administration of cloprostenol on interval to subsequent ovulation. A secondary objective was to determine the incidence of hemorrhagic anovulatory follicle (HAF) formation after PGF administration. Reproductive records of 275 mares monitored over a total of 520 estrous cycles were evaluated. All mares received a single intramuscular dose of 250 mg of the synthetic PGF analog cloprostenol sodium between days 5 and 12 after ovulation. The average interval from PGF to ovulation was 8.4 AE 2.5 days. The interval from PGF administration to subsequent ovulation was inversely proportional to the diameter of the largest follicle at the time of treatment. Administration of cloprostenol to mares with a large (!35 mm in diameter) diestrous follicle resulted in one of three outcomesdovulation within 48 hours (13.4%) with variable uterine edema, ovulation after 48 hours usually accompanied by the presence of uterine edema (73.1%), or regression without ovulation followed by emergence and eventual ovulation of a new dominant follicle (13.4%). There was no effect of mare age or season on interval from PGF to ovulation. The overall incidence of HAF development after PGF administration in this study was low (2.5%).

Electroactive Polymer Actuators and Devices (EAPAD) 2017, 2017

3D printing technology has been used for rapid prototyping since 1980’s and is still developing i... more 3D printing technology has been used for rapid prototyping since 1980’s and is still developing in a way that can be used for customized products with complex design and miniature features. Among all the available 3D printing techniques, Fused Deposition Modeling (FDM) is one of the most widely used technologies because of its capability to build different structures by employing various materials. However, complexity of parts made by FDM is greatly limited by restriction of using support materials. Support materials are often used in FDM for several complex geometries such as fully suspended shapes, overhanging surfaces and hollow features. This paper describes an approach to 3D print a structure using silicone elastomer and polylactide fiber (PLA) by employing a novel support material that is soluble in water. This support material is melted sugar which can easily be prepared at a low cost. Sugar is a carbohydrate, which is found naturally in plants such as sugarcane and sugar beets; therefore, it is completely organic and eco-friendly. As another advantage, the time for removing this material from the part is considerably less than other commercially available support materials and it can be removed easily by warm water without leaving any trace. Experiments were done using an inexpensive desktop 3D printer to fabricate complex structures for use in soft robots. The results envision that further development of this system would contribute to a method of fabrication of complex parts with lower cost yet high quality.

Smart Materials in Additive Manufacturing, Volume 2 : 4D Printing Mechanics, Modeling, and Advanced Engineering Applications

Smart Materials and Structures, 2020

Materials & Design, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Bio-Design and Manufacturing, 2019

Highly deformable bodies are essential for numerous types of applications in all sorts of environ... more Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many biomimetic structures. Recently, soft robots are favored over rigid structures for their highly compliant material, high-deformation properties at low forces, and ability to operate in difficult environments. However, it is still challenging to fabricate complex designs that satisfy application constraints due to the combined effects of material properties, actuation method, and structural geometry on the performance of the soft robot. Therefore, a combination of a rigid joint and a soft body can help achieve modular robots with fully functional body morphology. Yet, the fabrication of soft parts requires extensive molding for complex shapes, which comprises several processes and can be time-consuming. In addition, molded connections between extremely soft materials and hard materials can be critical failing points. In this paper, we present a functionally graded 3D-printed joint-like structure actuated by novel contractile actuators. Functionally graded materials (FGMs) via 3D printing allow for extensive material property enhancement and control which warrant tunable functionalities of the system. The 3D-printed structure is made of 3 rigid ball and socket joints connected in series and actuated by integrating twisted and coiled polymer fishing line (TCP FL) actuators, which are confined in the FGM accordion-shaped channels. The implementation of the untethered TCP FL actuation system can be highly beneficial for deployment in environments that require low vibrations and silent actuation. The fishing line TCP actuators produce an actuation strain up to 40% and bend the joint up to 40° in any direction. The TCP FL can be actuated individually or as a group to control the bending trajectory of the modular joint, which is beneficial when deployed in areas that contain small crevices. Obtaining complex modes of bending, the FGM multidirectional joint demonstrated a great potential to achieve different functionalities such as crawling, rolling, swimming, or underwater exploration.

Active and Passive Smart Structures and Integrated Systems 2017, 2017

With increasing popularity of portable devices for outdoor activities, portable energy harvesting... more With increasing popularity of portable devices for outdoor activities, portable energy harvesting devices are coming into spot light. The next generation energy harvester which is called hybrid energy harvester can employ more than one mechanism in a single device to optimize portion of the energy that can be harvested from any source of waste energy namely motion, vibration, heat and etc. In spite of few recent attempts for creating hybrid portable devices, the level of output energy still needs to be improved with the intention of employing them in commercial electronic systems or further applications. Moreover, implementing a practical hybrid energy harvester in different application for further investigation is still challenging. This proposal is projected to incorporate a novel approach to maximize and optimize the voltage output of hybrid energy harvesters to achieve a greater conversion efficiency normalized by the total mass of the hybrid device than the simple arithmetic sum of the individual harvesting mechanisms. The energy harvester model previously proposed by Larkin and Tadesse [1] is used as a baseline and a continuous unidirectional rotation is incorporated to maximize and optimize the output. The device harvest mechanical energy from oscillatory motion and convert it to electrical energy through electromagnetic and piezoelectric systems. The new designed mechanism upgrades the device in a way that can harvest energy from both rotational and linear motions by using magnets. Likewise, the piezoelectric section optimized to harvest at least 10% more energy. To the end, the device scaled down for tested with different sources of vibrations in the immediate environment, including machinery operation, bicycle, door motion while opening and closing and finally, human motions. Comparing the results from literature proved that current device has capability to be employed in commercial small electronic devices for enhancement of battery usage or as a backup power source. [1] Larkin, Miles, and Yonas Tadesse. "HM-EH-RT: hybrid multimodal energy harvesting from rotational and translational motions." International Journal of Smart and Nano Materials 4.4 (2013): 257-285.

SPIE Proceedings, 2016

Energy harvesting from structure vibration, human motion or environmental source has been the foc... more Energy harvesting from structure vibration, human motion or environmental source has been the focus of researchers in the past few decades. This paper proposes a novel design that is suitable to harvest energy from human motions such as dancing or physical exercise and use the device to engage young students in Science, Technology, Engineering and Math (STEM) fields and outreach activities. The energy harvester (EH) device was designed for a dominant human operational frequency range of 1–5 Hz and it can be wearable by human. We proposed to incorporate different genres of music coupled with energy harvesting technologies for motivation and energy generation. Students will learn both science and art together, since the energy harvesting requires understanding basic physical phenomena and the art enables various physical movements that imparts the largest motion transfer to the EH device. Therefore, the systems are coupled to each other. Young people follow music updates more than robotics or energy harvesting researches. Most popular videos on YouTube and VEVO are viewed more than 100 million times. Perhaps, integrating the energy harvesting research with music or physical exercise might enhance students’ engagement in science, and needs investigation. A multimodal energy harvester consisting of piezoelectric and electromagnetic subsystems, which can be wearable in the leg, is proposed in this study. Three piezoelectric cantilever beams having permanent magnets at the ends are connected to a base through a slip ring. Stationary electromagnetic coils are installed in the base and connected in series. Whenever the device is driven by any oscillation parallel to the base, the unbalanced rotor will rotate generating energy across the stationary coils in the base. In another case, if the device is driven by an oscillation perpendicular to the base, a stress will be induced within the cantilever beams generating energy across the piezoelectric materials.

Electroactive Polymer Actuators and Devices (EAPAD) XX, 2018

Actuators are the most important elements that affect the performance of biorobotic systems desig... more Actuators are the most important elements that affect the performance of biorobotic systems design and development. One of the objectives of this project is to design stronger, lighter, 3D printable, functionally graded bone-like structures and bio-inspired musculoskeletal system for the articulation of robots. Another objective is to identify the fundamental science of manufacturing and modeling of the muscle systems. A modular building block is presented consisting of bone-like structures, cartilages and artificial muscles (that are inexpensive and powerful), which can be cascaded to create complex robots. In this paper, we present terrestrial robots as a demonstration of the building blocks for biorobotic systems. We particularly illustrate a humanoid robot developed using soft actuators based on twisted and coiled polymer (TCP) muscles. The integration of TCPs in biorobotic systems has some challenges to overcome such as initial pre-stress, adding multiple actuators in parallel or in antagonistic pair and speed of actuation and other accessories. We will quantify the performance of these robots experimentally. We presented two TCP muscles types, one without heating element and the other one that incorporates a heating element that allows electrical actuation.

Smart Materials and Structures, 2020

Jellyfish are energy-efficient swimmers due to the muscle-powered flapping of their soft bell tha... more Jellyfish are energy-efficient swimmers due to the muscle-powered flapping of their soft bell that facilitates a unique energy recapture mechanism. In this paper, we present a bio-inspired jellyfish robot named Poly-Saora that mimics the swimming behavior of the jellyfish species Black sea nettle (Chrysaora achlyos). An assembly-based fabrication method is used to create the Poly-Saora that is developed mainly with polymeric materials (95% of the robot by volume). Twisted and coiled polymer (TCP) actuators are successfully implemented in this robot and show great potential for underwater applications. The influence of different parameters such as the amplitude of the input power, the actuation frequency, and the lifecycle of the actuator are investigated underwater. A full characterization of 6-ply TCP muscles is demonstrated. An actuation strain of ∼10 % is achieved in water at a frequency of 0.1Hz and 50 kPa load. When integrated into the jellyfish, the TCP was able to bend a single bell by 17˚. Poly-Saora was able to swim a vertical distance of 180 mm in 220 s with four TCP actuators each confined in a separate conduit. The robot mimics the swimming behavior of a real jellyfish by contracting the bell segments through the activation of the actuators, which generates forced water circulation under the bell in a pulsating rhythm, consequently creating a vertical movement of the robot. Overall, Poly-Saora is presenting a model of an underwater system that is driven by stimuli-responsive polymer materials and has unique advantages over conventional rigid robots due to their lightweight, muscle-like structures, silent actuation and ease of manufacturing. This robot can be used for safe interaction with other underwater species and their natural habitats when fully developed.

Composite Structures, 2018

Multimaterial additive manufacturing technique is a great alternative approach for fabrication of... more Multimaterial additive manufacturing technique is a great alternative approach for fabrication of complex structures with diverse mechanical properties compared to traditional assembly process. Fused deposition modeling is a simple, popular and affordable technique, which is available in numerous desktop 3D printers nowadays. However, this technology is not developed considerably to co-fabricate highly stretchable (800% strain) elastomer materials with low stiffness and high strength parts in one single build platform. In this paper, a single step fabrication of a novel bioinspired joint system, consisting of dissimilar materials with high strength and high strain elements is developed by an inexpensive 3D printer. The joint consists of continuous metal fibers reinforced thermoplastic part that resembles bones and soft elastomer that mimics soft tissues. Tensile test results of the 3D printed reinforced thermoplastic part showed a 78% increase in strength, which can be competed with natural bone. Highly stretchable elastomer is used for the soft parts that was directly 3D printed and simultaneously cured by heating. Overall, a simple and cost effective heterogeneous material manufacturing technique is developed that maintained high mechanical strength and sufficient elasticity, to produce a bioinspired joint that composed of a rigid skeleton covered by a very soft elastomer.

Desalination, 2015

Prostaglandin F2a (PGF) treatment is routinely used in the reproductive management of mares to in... more Prostaglandin F2a (PGF) treatment is routinely used in the reproductive management of mares to induce luteolysis and allow a subsequent return to estrus. The objective of this retrospective study was to assess the effect of follicle size at the time of administration of cloprostenol on interval to subsequent ovulation. A secondary objective was to determine the incidence of hemorrhagic anovulatory follicle (HAF) formation after PGF administration. Reproductive records of 275 mares monitored over a total of 520 estrous cycles were evaluated. All mares received a single intramuscular dose of 250 mg of the synthetic PGF analog cloprostenol sodium between days 5 and 12 after ovulation. The average interval from PGF to ovulation was 8.4 AE 2.5 days. The interval from PGF administration to subsequent ovulation was inversely proportional to the diameter of the largest follicle at the time of treatment. Administration of cloprostenol to mares with a large (!35 mm in diameter) diestrous follicle resulted in one of three outcomesdovulation within 48 hours (13.4%) with variable uterine edema, ovulation after 48 hours usually accompanied by the presence of uterine edema (73.1%), or regression without ovulation followed by emergence and eventual ovulation of a new dominant follicle (13.4%). There was no effect of mare age or season on interval from PGF to ovulation. The overall incidence of HAF development after PGF administration in this study was low (2.5%).

Electroactive Polymer Actuators and Devices (EAPAD) 2017, 2017

3D printing technology has been used for rapid prototyping since 1980’s and is still developing i... more 3D printing technology has been used for rapid prototyping since 1980’s and is still developing in a way that can be used for customized products with complex design and miniature features. Among all the available 3D printing techniques, Fused Deposition Modeling (FDM) is one of the most widely used technologies because of its capability to build different structures by employing various materials. However, complexity of parts made by FDM is greatly limited by restriction of using support materials. Support materials are often used in FDM for several complex geometries such as fully suspended shapes, overhanging surfaces and hollow features. This paper describes an approach to 3D print a structure using silicone elastomer and polylactide fiber (PLA) by employing a novel support material that is soluble in water. This support material is melted sugar which can easily be prepared at a low cost. Sugar is a carbohydrate, which is found naturally in plants such as sugarcane and sugar beets; therefore, it is completely organic and eco-friendly. As another advantage, the time for removing this material from the part is considerably less than other commercially available support materials and it can be removed easily by warm water without leaving any trace. Experiments were done using an inexpensive desktop 3D printer to fabricate complex structures for use in soft robots. The results envision that further development of this system would contribute to a method of fabrication of complex parts with lower cost yet high quality.