Pub Date : 2024-07-02DOI: 10.1088/1361-665x/ad59e4
Rafael Augusto Gomes, Lucas Antonio de Oliveira, Matheus Brendon Francisco and Guilherme Ferreira Gomes
Mechanical structures abilities to absorb and dissipate energy have a variety of applications in daily life, including the ability to dampen mechanical vibrations and shock effects. In the present study, inspired by the dragonfly wing (DFW) shape, a novel auxetic unit cell was developed with the goal of proposing a novel structure with a lower stress concentrator and consequently increasing energy absorption. The negative Poisson’s ratio behavior was also studied. The DFW shaped unit cells were applied in a tubular structure, and the experimental samples were produced utilizing an additive manufacturing process with polylactic acid filament. To validate the ability to absorb energy of the novel unit cell, a comparison was proposed with the classical reentrant auxetic tubular structure following two different parameters: weight and the number of unit cells being developed in two different DFW structures. The study of the novel unit cell was performed using finite element analysis and experimental testing, and excellent agreement was observed between them. As a result, the bio-inspired DFWs shape in both configurations proposed when compared to the classical reentrant presented an excellent result in terms of absorbing energy, where the structure with the same quantity of unit cells and the structure with the same weight respectively absorb 163% and 79% when compared to the classical Reentrant, finally the new structure presented the negative Poisson’s ratio of −0.5, presenting an auxetic behavior and being able to resist more force and displacement
{"title":"A novel dragonfly wing shape auxetic tubular structure with negative Poisson’s ratio","authors":"Rafael Augusto Gomes, Lucas Antonio de Oliveira, Matheus Brendon Francisco and Guilherme Ferreira Gomes","doi":"10.1088/1361-665x/ad59e4","DOIUrl":"https://doi.org/10.1088/1361-665x/ad59e4","url":null,"abstract":"Mechanical structures abilities to absorb and dissipate energy have a variety of applications in daily life, including the ability to dampen mechanical vibrations and shock effects. In the present study, inspired by the dragonfly wing (DFW) shape, a novel auxetic unit cell was developed with the goal of proposing a novel structure with a lower stress concentrator and consequently increasing energy absorption. The negative Poisson’s ratio behavior was also studied. The DFW shaped unit cells were applied in a tubular structure, and the experimental samples were produced utilizing an additive manufacturing process with polylactic acid filament. To validate the ability to absorb energy of the novel unit cell, a comparison was proposed with the classical reentrant auxetic tubular structure following two different parameters: weight and the number of unit cells being developed in two different DFW structures. The study of the novel unit cell was performed using finite element analysis and experimental testing, and excellent agreement was observed between them. As a result, the bio-inspired DFWs shape in both configurations proposed when compared to the classical reentrant presented an excellent result in terms of absorbing energy, where the structure with the same quantity of unit cells and the structure with the same weight respectively absorb 163% and 79% when compared to the classical Reentrant, finally the new structure presented the negative Poisson’s ratio of −0.5, presenting an auxetic behavior and being able to resist more force and displacement","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mushroom-shape gecko-inspired adhesive has been extensively studied and applied in a wide range of fields. However, current research primarily focuses on enhancing its adhesion properties, necessitating further exploration in strategies of detachment and adaptation, which significantly constrain its practical applications. In this study, a stiffness variable gripper with controllable adhesion and fast response is developed by integrating mushroom-shape adhesive with granular jamming technology. A theoretical model for the detachment of the gripper is established, indicating the effect of backing stiffness on adhesion performance, which is verified through contact area observations and adhesion experiments. The proposed modulation method demonstrates an impressive adhesion-to-detachment ratio of 92.8, with adhesion capacity of up to 41.023 N and detachment force of only 0.442 N. The switch time is remarkably fast at just 0.5 s. Additionally, the designed gripper, under pressure difference of 60 kPa, is able to stably grasp smooth objects with various shapes weighing over 2 kg, with a load-to-weight ratio of approximately 8, and a minimal power consumption of only 4.404 W. The work here presents a comprehensive understanding of adhesion modulation of fibrillar adhesive through granular jamming, and provides new insights into robust reversible adhesion design for related technologies.
{"title":"Fast stiffness variation gripper with efficient adhesion control","authors":"Wenqing Chen, Tianhui Sun, Jingyang Li, Xiaosong Li, Lvzhou Li, Yonggang Meng and Yu Tian","doi":"10.1088/1361-665x/ad5a59","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5a59","url":null,"abstract":"The mushroom-shape gecko-inspired adhesive has been extensively studied and applied in a wide range of fields. However, current research primarily focuses on enhancing its adhesion properties, necessitating further exploration in strategies of detachment and adaptation, which significantly constrain its practical applications. In this study, a stiffness variable gripper with controllable adhesion and fast response is developed by integrating mushroom-shape adhesive with granular jamming technology. A theoretical model for the detachment of the gripper is established, indicating the effect of backing stiffness on adhesion performance, which is verified through contact area observations and adhesion experiments. The proposed modulation method demonstrates an impressive adhesion-to-detachment ratio of 92.8, with adhesion capacity of up to 41.023 N and detachment force of only 0.442 N. The switch time is remarkably fast at just 0.5 s. Additionally, the designed gripper, under pressure difference of 60 kPa, is able to stably grasp smooth objects with various shapes weighing over 2 kg, with a load-to-weight ratio of approximately 8, and a minimal power consumption of only 4.404 W. The work here presents a comprehensive understanding of adhesion modulation of fibrillar adhesive through granular jamming, and provides new insights into robust reversible adhesion design for related technologies.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1361-665x/ad5b30
Limin Ren, Shuqing Wang, Wenqiang Zhang, Yubao Cao, Pan Zhang, Xinyu Wang and Yisong Tan
Recovering kinetic energy from the environment is mostly focused on the natural environment, while there is also a huge energy in the human living environment. The swing door is an indispensable equipment in the human living environment. The bidirectional swing of the door opening and closing process is rich in energy generated by human motion and thus has a large potential for energy recovery. An energy harvester for recovering bidirectional kinetic energy of the door in buildings is proposed, fabricated, analyzed, and tested. The energy harvester consists of a parallel crank-slider mechanism, a transmission mechanism and a power generation module. The external linkage is used to connect the door and the energy harvester to transmit the bidirectional swing of the door. The parallel crank-slider mechanism is coupled with two one-way bearings. This can realize the conversion of the bidirectional swing of the door to the unidirectional rotation of the central shaft. The final mechanical rectification effect is achieved. Kinematic and dynamic analyses are performed to determine the factors affecting the power generation performance. A prototype is fabricated, and experiments are conducted on it by simulating the process of opening and closing the door. The experimental results are consistent with the simulation ones. At a normal opening velocity of 90° s−1, the maximum open-circuit voltage of the harvester is 7.06 V and the average output power is 1.03 W. The highest efficiency of the harvester can reach 69.65%. The recovered energy is capable of powering the smart door lock for at least 150 s, as well as powering devices such as door lights and doorbells. This can meet the power supply needs of most electronic devices on doors in human life.
{"title":"Recovering energy from door opening and closing process using a parallel crank-slider harvester in buildings","authors":"Limin Ren, Shuqing Wang, Wenqiang Zhang, Yubao Cao, Pan Zhang, Xinyu Wang and Yisong Tan","doi":"10.1088/1361-665x/ad5b30","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5b30","url":null,"abstract":"Recovering kinetic energy from the environment is mostly focused on the natural environment, while there is also a huge energy in the human living environment. The swing door is an indispensable equipment in the human living environment. The bidirectional swing of the door opening and closing process is rich in energy generated by human motion and thus has a large potential for energy recovery. An energy harvester for recovering bidirectional kinetic energy of the door in buildings is proposed, fabricated, analyzed, and tested. The energy harvester consists of a parallel crank-slider mechanism, a transmission mechanism and a power generation module. The external linkage is used to connect the door and the energy harvester to transmit the bidirectional swing of the door. The parallel crank-slider mechanism is coupled with two one-way bearings. This can realize the conversion of the bidirectional swing of the door to the unidirectional rotation of the central shaft. The final mechanical rectification effect is achieved. Kinematic and dynamic analyses are performed to determine the factors affecting the power generation performance. A prototype is fabricated, and experiments are conducted on it by simulating the process of opening and closing the door. The experimental results are consistent with the simulation ones. At a normal opening velocity of 90° s−1, the maximum open-circuit voltage of the harvester is 7.06 V and the average output power is 1.03 W. The highest efficiency of the harvester can reach 69.65%. The recovered energy is capable of powering the smart door lock for at least 150 s, as well as powering devices such as door lights and doorbells. This can meet the power supply needs of most electronic devices on doors in human life.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141530526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-30DOI: 10.1088/1361-665x/ad59e7
Huifang Xiao, Xuyang Guan, Fan Zhang, Gang Liang, Yihu Tang and Chris Bowen
Gear transmission systems are crucial components for transmitting power and motion in a host of engineering applications. Recently, the potential to embed sensors into transmission components has attracted significant attention for accurate condition monitoring of system health. As a result, embedded sensors must operate in a safe and stable manner, whilst being able to provide a continuous power-supply and ensure operational autonomy. In this work, a magnetically coupled beam-type piezoelectric energy harvester is developed for energy harvesting of rotational centrifugal forces and individual gear meshing excitation events. A new coupled electromechanical dynamic model is developed to explain the working principle and response of the harvester when excited by a combination of gear meshing excitation events, a centrifugal force, and a magnetic force. Since gear meshing events are observed to lead to an increased hardening nonlinearity of the energy harvester, and a decrease in power output, a novel variable-section cantilever structure was developed. Our detailed theoretical analysis demonstrates that the novel variable stiffness structure improves both the power output and bandwidth, with excellent agreement with experimental measurements. This work provides new theoretical insights into the application of magnetically coupled piezoelectric energy harvesters for self-powered sensing systems for critical gear transmission systems.
{"title":"Modelling and characterisation of a magnetically coupled piezoelectric beam for energy harvesting gear meshing motion","authors":"Huifang Xiao, Xuyang Guan, Fan Zhang, Gang Liang, Yihu Tang and Chris Bowen","doi":"10.1088/1361-665x/ad59e7","DOIUrl":"https://doi.org/10.1088/1361-665x/ad59e7","url":null,"abstract":"Gear transmission systems are crucial components for transmitting power and motion in a host of engineering applications. Recently, the potential to embed sensors into transmission components has attracted significant attention for accurate condition monitoring of system health. As a result, embedded sensors must operate in a safe and stable manner, whilst being able to provide a continuous power-supply and ensure operational autonomy. In this work, a magnetically coupled beam-type piezoelectric energy harvester is developed for energy harvesting of rotational centrifugal forces and individual gear meshing excitation events. A new coupled electromechanical dynamic model is developed to explain the working principle and response of the harvester when excited by a combination of gear meshing excitation events, a centrifugal force, and a magnetic force. Since gear meshing events are observed to lead to an increased hardening nonlinearity of the energy harvester, and a decrease in power output, a novel variable-section cantilever structure was developed. Our detailed theoretical analysis demonstrates that the novel variable stiffness structure improves both the power output and bandwidth, with excellent agreement with experimental measurements. This work provides new theoretical insights into the application of magnetically coupled piezoelectric energy harvesters for self-powered sensing systems for critical gear transmission systems.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-30DOI: 10.1088/1361-665x/ad59e5
Cai Qinlin, Lu Ping, Chen Yuanbin and Shi Xiang
Energy-harvesting vibration control strategy has been proposed and applied in different applications, including but not limited to automotive, mechanical, and civil engineering. However, when facing uncertainties from both internal and external environments, the robustness of its performance has rarely been evaluated. The energy-harvesting tuned mass damper (EHTMD) is a representative vibration control device integrated with the energy-harvesting function. This study investigates the robustness of an EHTMD installed on a structure with multi-uncertainties. First, the EHTMD modeling, the interval model, and the robustness evaluation framework are introduced. Uncertainties are considered for all parameters of an EHTMD, including the mechanical units, electromagnetic damper, and energy harvesting circuit. Subsequently, a series of dynamic simulations are performed on a damped benchmark single-degree-of-freedom frame with an EHTMD. The lower- and upper-bound structural vibration and generated power are estimated under free-vibration, harmonic-excitation, and random-excitation scenarios. The EHTMD performance robustness is evaluated through the interval response by incorporating the first-passage theory. The key factors in EHTMD that influence its robustness are identified. Results indicate promising robustness when using the energy-harvesting vibration control strategy to replace the conventional dampers, addressing one of the often-questioned issues of the energy-harvesting vibration control strategy.
{"title":"Robustness analysis for the vibration control performance of energy-harvesting tuned mass damper with uncertainties","authors":"Cai Qinlin, Lu Ping, Chen Yuanbin and Shi Xiang","doi":"10.1088/1361-665x/ad59e5","DOIUrl":"https://doi.org/10.1088/1361-665x/ad59e5","url":null,"abstract":"Energy-harvesting vibration control strategy has been proposed and applied in different applications, including but not limited to automotive, mechanical, and civil engineering. However, when facing uncertainties from both internal and external environments, the robustness of its performance has rarely been evaluated. The energy-harvesting tuned mass damper (EHTMD) is a representative vibration control device integrated with the energy-harvesting function. This study investigates the robustness of an EHTMD installed on a structure with multi-uncertainties. First, the EHTMD modeling, the interval model, and the robustness evaluation framework are introduced. Uncertainties are considered for all parameters of an EHTMD, including the mechanical units, electromagnetic damper, and energy harvesting circuit. Subsequently, a series of dynamic simulations are performed on a damped benchmark single-degree-of-freedom frame with an EHTMD. The lower- and upper-bound structural vibration and generated power are estimated under free-vibration, harmonic-excitation, and random-excitation scenarios. The EHTMD performance robustness is evaluated through the interval response by incorporating the first-passage theory. The key factors in EHTMD that influence its robustness are identified. Results indicate promising robustness when using the energy-harvesting vibration control strategy to replace the conventional dampers, addressing one of the often-questioned issues of the energy-harvesting vibration control strategy.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141530527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-30DOI: 10.1088/1361-665x/ad5a58
Chunbing Zhang, Xiaofeng Liu, Daiping Wei and Lin Bo
For the problem of fatigue damage detection and damage degree assessment of plate structures, a quantitative damage assessment method based on the fast self-organizing feature mapping (FSOM) algorithm is proposed in this paper. The damage detection problem is transformed into a binary classification problem by extracting multidimensional damage features of the Lamb wave signal in plate to be detected and selecting damage sensitive features. Then, the FSOM network is used to identify the health state of the plate to be inspected, and the damage index is obtained by fusing the damage sensitive features using FSOM to quantitatively evaluate the damage level of the plate to be inspected. Simulation and experimental results show this method has a good dynamic tracking capability for the fatigue damage evolution of aluminum and composite plates, and can achieve quantitative assessment of fatigue damage of plate structures.
{"title":"Quantitative characterization of fatigue damage in plate structures based on FSOM","authors":"Chunbing Zhang, Xiaofeng Liu, Daiping Wei and Lin Bo","doi":"10.1088/1361-665x/ad5a58","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5a58","url":null,"abstract":"For the problem of fatigue damage detection and damage degree assessment of plate structures, a quantitative damage assessment method based on the fast self-organizing feature mapping (FSOM) algorithm is proposed in this paper. The damage detection problem is transformed into a binary classification problem by extracting multidimensional damage features of the Lamb wave signal in plate to be detected and selecting damage sensitive features. Then, the FSOM network is used to identify the health state of the plate to be inspected, and the damage index is obtained by fusing the damage sensitive features using FSOM to quantitatively evaluate the damage level of the plate to be inspected. Simulation and experimental results show this method has a good dynamic tracking capability for the fatigue damage evolution of aluminum and composite plates, and can achieve quantitative assessment of fatigue damage of plate structures.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141530528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-30DOI: 10.1088/1361-665x/ad5a5b
Zihui Zhu, Yang Yang, Shaoyang Yan, Songyan Wang, Yuan Xie, Yili Fu, Yunquan Li and Pei Jiang
Pneumatically driven soft actuators with sensors have been developing rapidly these years. They can perceive external stimulus and be applied to different scenarios. In this study, we present a novel soft robotic finger with sensorized finger pulp based on sealing a flexible fabric piezoresistive film called Velostat into a pre-charged air bag, which can perceive the contact force with an object based on changes in resistance value of the sensor. The soft sensor mimics human finger pulp and deforms passively according to the shape of objects during grasping, so that it can firmly contact with objects and as such improves the gripper’s grasping stability. Moreover, based on force feedback, the actuator can reduce or increase the input pressure to hold the object and control the contact force precisely. The sensor exhibits a sensitivity of up to 0.328 kPa−1 and can measure pressures ranging from 0 to over 10 kPa. The sensor’s measurement range and sensitivity can be pre-adjusted by regulating the pre-charged pressure during fabrication for different grasping tasks. The response/recovery time of the sensor is 80/60 ms on average. Experiments show that the finger with sensorized pulp can be applied for object softness and size detection, object transport minitoring as well as force control grasping. The proposed soft robotic finger has potential for applications in scenarios that require safe contact and closed-loop control.
{"title":"Soft robotic fingers with sensorized pre-charged finger pulp","authors":"Zihui Zhu, Yang Yang, Shaoyang Yan, Songyan Wang, Yuan Xie, Yili Fu, Yunquan Li and Pei Jiang","doi":"10.1088/1361-665x/ad5a5b","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5a5b","url":null,"abstract":"Pneumatically driven soft actuators with sensors have been developing rapidly these years. They can perceive external stimulus and be applied to different scenarios. In this study, we present a novel soft robotic finger with sensorized finger pulp based on sealing a flexible fabric piezoresistive film called Velostat into a pre-charged air bag, which can perceive the contact force with an object based on changes in resistance value of the sensor. The soft sensor mimics human finger pulp and deforms passively according to the shape of objects during grasping, so that it can firmly contact with objects and as such improves the gripper’s grasping stability. Moreover, based on force feedback, the actuator can reduce or increase the input pressure to hold the object and control the contact force precisely. The sensor exhibits a sensitivity of up to 0.328 kPa−1 and can measure pressures ranging from 0 to over 10 kPa. The sensor’s measurement range and sensitivity can be pre-adjusted by regulating the pre-charged pressure during fabrication for different grasping tasks. The response/recovery time of the sensor is 80/60 ms on average. Experiments show that the finger with sensorized pulp can be applied for object softness and size detection, object transport minitoring as well as force control grasping. The proposed soft robotic finger has potential for applications in scenarios that require safe contact and closed-loop control.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-27DOI: 10.1088/1361-665x/ad59e6
Jinmeng Zha and Zhen Zhang
Negative compressibility metamaterials have attracted significant attention due to their distinctive properties and promising applications. Negative compressibility has been interpreted in two ways. Regarding the negative compressibility induced by a uniaxial load, it can only occur abruptly when the load reaches a certain threshold. Hence, it can be termed as transient negative compressibility. However, fabrication and experiments of such metamaterials have rarely been reported. Herein, we demonstrate them. Inspired by Braess’s paradox, a novel mechanical model is proposed with reversible negative compressibility. It shows multiple types of force responses during a loading-unloading cycle, including transient negative compressibility and hysteresis. Phase diagrams are employed to visualize the relationship between force responses and system parameters. Besides, explicit expressions for the conditions and intensity of negative compressibility are obtained for design and optimization. The model replacement method inspired by compliant mechanism design is then introduced to derive specific unit cell structures, thus avoiding intuition-based approaches. Additive manufacturing technology is utilized to fabricate the prototypes, and negative compressibility is validated via simulations and experiments. Furthermore, it is demonstrated that metamaterials with transient negative compressibility can be activated through electrical heating and can function as actuators, thereby possessing machine-like properties. The proposed mechanical metamaterial and the introduced design methodology have potentials to impact micro-electromechanical systems, force sensors, protective devices, and other applications.
{"title":"Reversible negative compressibility metamaterials inspired by Braess’s Paradox","authors":"Jinmeng Zha and Zhen Zhang","doi":"10.1088/1361-665x/ad59e6","DOIUrl":"https://doi.org/10.1088/1361-665x/ad59e6","url":null,"abstract":"Negative compressibility metamaterials have attracted significant attention due to their distinctive properties and promising applications. Negative compressibility has been interpreted in two ways. Regarding the negative compressibility induced by a uniaxial load, it can only occur abruptly when the load reaches a certain threshold. Hence, it can be termed as transient negative compressibility. However, fabrication and experiments of such metamaterials have rarely been reported. Herein, we demonstrate them. Inspired by Braess’s paradox, a novel mechanical model is proposed with reversible negative compressibility. It shows multiple types of force responses during a loading-unloading cycle, including transient negative compressibility and hysteresis. Phase diagrams are employed to visualize the relationship between force responses and system parameters. Besides, explicit expressions for the conditions and intensity of negative compressibility are obtained for design and optimization. The model replacement method inspired by compliant mechanism design is then introduced to derive specific unit cell structures, thus avoiding intuition-based approaches. Additive manufacturing technology is utilized to fabricate the prototypes, and negative compressibility is validated via simulations and experiments. Furthermore, it is demonstrated that metamaterials with transient negative compressibility can be activated through electrical heating and can function as actuators, thereby possessing machine-like properties. The proposed mechanical metamaterial and the introduced design methodology have potentials to impact micro-electromechanical systems, force sensors, protective devices, and other applications.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-27DOI: 10.1088/1361-665x/ad588e
B Van Damme, R Weber, J U Schmied, A Spierings and A Bergamini
Piezoelectric transducers applied on or integrated in structures, combined with appropriate circuits have been extensively investigated as a smart approach to the mitigation of resonant vibrations with high relative amplitudes. A resonant shunt circuit consisting of the capacitive piezoelectric transducer and an inductance can be configured to target specific eigenmodes of a structure, if appropriately placed and tuned. Their effect is expressed in terms of mechanical impedance of the host structure, allowing for the exchange of energy between the mechanical and electrical domain, to dramatically affect the dynamic response of the structure. By re-framing the function of resonant shunted piezoelectric transducers as frequency dependent variable stiffness elements, this paper investigates their capability to realize a frequency dependent structural mechanical connectivity, where the load path within a lattice structure can be interrupted at will for specific frequencies by tunable null-stiffness components. Here, we offer the numerical and experimental verification of this idea, by demonstrating the ability to significantly affect the dynamic response of a unit cell of an adaptive lattice metamaterial, even away from a structural resonance. In the latter case, the null-stiffness shunt leads to an additional resonance peak in the truss’ dynamic response. Its realization as additively manufactured component points to the feasibility of such structures in real life.
{"title":"Implementation of tunable frequency-dependent stiffness elements via integrated shunted piezoelectric stacks","authors":"B Van Damme, R Weber, J U Schmied, A Spierings and A Bergamini","doi":"10.1088/1361-665x/ad588e","DOIUrl":"https://doi.org/10.1088/1361-665x/ad588e","url":null,"abstract":"Piezoelectric transducers applied on or integrated in structures, combined with appropriate circuits have been extensively investigated as a smart approach to the mitigation of resonant vibrations with high relative amplitudes. A resonant shunt circuit consisting of the capacitive piezoelectric transducer and an inductance can be configured to target specific eigenmodes of a structure, if appropriately placed and tuned. Their effect is expressed in terms of mechanical impedance of the host structure, allowing for the exchange of energy between the mechanical and electrical domain, to dramatically affect the dynamic response of the structure. By re-framing the function of resonant shunted piezoelectric transducers as frequency dependent variable stiffness elements, this paper investigates their capability to realize a frequency dependent structural mechanical connectivity, where the load path within a lattice structure can be interrupted at will for specific frequencies by tunable null-stiffness components. Here, we offer the numerical and experimental verification of this idea, by demonstrating the ability to significantly affect the dynamic response of a unit cell of an adaptive lattice metamaterial, even away from a structural resonance. In the latter case, the null-stiffness shunt leads to an additional resonance peak in the truss’ dynamic response. Its realization as additively manufactured component points to the feasibility of such structures in real life.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-26DOI: 10.1088/1361-665x/ad5a5a
Xiaolei Wang, Haibo Qu, Kai Zhao, Xiao Yang and Sheng Guo
Origami has attracted more and more attention due to its exotic mechanical properties, and the inspired metamaterials are also popular. However, the main focus of current research is on existing origami patterns and properties, although new origami patterns or results that expand on existing origami patterns are gradually emerging. In this paper, we summarize a series of derived structures of the Kresling origami, demonstrating more stable states and richer structural forms. At the same time, a point-searching method is proposed along the ideas of the truss model, which is effective for irregular stable states of these derived structures. On this basis, we create an origami-inspired mechanical metamaterial with foldable property and high load-bearing capacity, fabricate the prototype, and validate its performance through experiments. These works make important contributions for promoting the Kresling origami and origami-inspired metamaterials.
{"title":"Kresling origami derived structures and inspired mechanical metamaterial","authors":"Xiaolei Wang, Haibo Qu, Kai Zhao, Xiao Yang and Sheng Guo","doi":"10.1088/1361-665x/ad5a5a","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5a5a","url":null,"abstract":"Origami has attracted more and more attention due to its exotic mechanical properties, and the inspired metamaterials are also popular. However, the main focus of current research is on existing origami patterns and properties, although new origami patterns or results that expand on existing origami patterns are gradually emerging. In this paper, we summarize a series of derived structures of the Kresling origami, demonstrating more stable states and richer structural forms. At the same time, a point-searching method is proposed along the ideas of the truss model, which is effective for irregular stable states of these derived structures. On this basis, we create an origami-inspired mechanical metamaterial with foldable property and high load-bearing capacity, fabricate the prototype, and validate its performance through experiments. These works make important contributions for promoting the Kresling origami and origami-inspired metamaterials.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141530529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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