Macro Fiber Research Articles

Flexural Behavior of Lightweight Concrete Beams Reinforced with GFRP Bars and Effects of the Added Micro and Macro Fiber

This study evaluated the effect of macro steel fiber (SF), micro glass fiber (GF) and micro polypropylene fiber (PF) in lightweight aggregate concrete, (LWAC) beams reinforced with glass fiber reinforced polymer (GFRP) bars. Firstly, concrete mixtures with different volume fractions of GF, PF and SF were tested up to compressive strength, then determine the optimum fiber content GF, PF and SF added into LWAC mix by 0.3%, 0.8% and 0.25% by the volume of concrete, respectively. Meanwhile, eight rectangular cross-section beams with 100 mm (width) × 200 mm (depth) × 1500 mm (length) were tested by four-point bending beam test up to the ultimate load. The GFRP bars were used to reinforce all beams. The failure modes, load-deflection behavior, ductility, flexural capacity and energy absorption were compared in the test results. The experimental results shown added fibers into LWAC improved the flexural capacity, ductility and energy absorption also enhanced moment capacity by 10.07% to 110%. The results indicated that failure modes of GF and PF specimens were in good consistency with the ACI 440.1R-06 predicted failure modes, but for SF specimens, only concrete crushing failure modes accrued. At the end step, the correction factor ( ) obtained from calculated of the experimental results with the flexural capacity according to the ACI 440.1R-06 and ISIS design manual No. 3.

Wireless stress sensor based on piezoelectric energy harvesting for a rotating shaft

A shaft is a mechanical component which transmits mechanical power and torque. A failure of the shaft may result in serious damage to machine in operation. Contact or noncontact monitoring techniques of rotating shaft have been developed in order to prevent this damage. The application of contact monitoring techniques requires the use of additional devices. First of all, a slip ring assembly, which enables a sensor supply and a sending of measurement data from a rotating shaft to some receivers. The use of the slip ring assembly, which requires an access to the front of the rotating shaft and an additional channel located in an inside of this shaft, are the most important weaknesses of contact techniques. In contrast to these approaches, the article presents a contact technique of stress monitoring in the rotating shaft, in which the slip ring assembly is not required. Presented contact technique consists of a wireless sensor based on piezoelectric energy harvester and a radio transmission system. The piezoelectric energy harvester consists of Macro Fiber Composite (MFC) patch and a system of energy storage and energy transfer control. MFC patch is directly glued to the rotating shaft surface and product an amount of electric energy which is enough to supply only a radio transmitter. Such built wireless sensor based on piezoelectric energy harvester was tested in laboratory stand which contained a rotating shaft with a system of force generation, a belt transmission with a system of generation of rotational motion, and a measurement system. The time between radio signals was measured for selected values of the rate of rotation of the shaft and for selected values of stress in the shaft in laboratory experiments. The experiments showed that dependence between the value of stress in the shaft and the number of radio signals per second can be approximated by a straight line. A method of measurement of stress in the rotating shaft was elaborated on the basis of the experiments. The method is based on the number of radio signals per second, which is linearly correlated with an average value of stress in the shaft, for the known value of the rate of rotation of the monitored shaft. The elaborated piezoelectric wireless sensor of stress were tested as a main part of sensor of cracks in the shaft surface in the last experiments. The time, after which the crack was detected, depended on a sampling period of such piezoelectric wireless sensor. The sampling period in turn depended on the three parameters: an average value of stress in a place where MFC patch is glued, the rate of rotation of shaft, a capacity of capacitor in a system of energy storage in a piezoelectric energy harvester.

Topographical analysis of fractured surface roughness of macro fiber reinforced concrete and its correlation with flexural toughness

Macro fibers reinforcement is considered to be an effective way to improve the flexural toughness of the concrete. With growing public interest in wide-spread use of fiber reinforced concrete (FRC), the need for understanding and evaluating micro fiber reinforcement mechanism is on the rise. In this study, concretes were reinforced by various dopant amounts of macro polypropylene (PP) fiber or steel fiber (SF) or their mixtures, topographical analysis was applied on a fractured concrete surface by using a custom-built 3-D laser scanning equipment, and the tested surface was fractured by using a three-point bending beam test. The topographical analysis results were evaluated quantitatively by roughness parameters of roughness number (RN), fractal dimension (D), standard deviation of height distribution (σz), and arithmetic mean deviation of the surface topography (Ha). Multivariate analysis suggests the most effective of roughness number (RN) for evaluating the roughness of fractured surface. Furthermore, the RN of fractured surface was further correlated to the flexural toughness of the concrete, the relation between the fractured concrete surface roughness (RN) and flexural toughness follows an exponential function, which can be employed to quickly estimate its roughness of fractured surface by flexural toughness of the FRC. In conclusion, from the developed topographical analysis method, the hybrid fibers reinforced concrete shows the most significant improvement of the flexural toughness of the concrete, which suggests hybrid fiber reinforcement shall be a future solution for commercialization of the FRC in terms of high toughness and high durability.

Hubungan Asupan Zink, Magnesium, dan Serat dengan Kadar Gula Darah Puasa Pasien Diabetes Mellitus Tipe 2 di RS PKU Muhammadiyah Temanggung

Diabetes Mellitus (DM) type 2 occurs because of insulin resistance, on of the contributing factors is the lack of intake of micronutrients (zinc and magnesium) and macro (fiber). The prevalence of DM in Temanggung is 1,6%. There are 45 patients suffering from type 2 diabetes at PKU Muhammadiyah Hospital in Temanggung which have zinc, magnesium, and fiber intake below normal (deficit). The study aims to analyze the relationship of zinc, magnesium, and fiber intake with fasting blood sugar levels at PKU Muhammadiyah Hospital in Temanggung. The research is a cross sectional design with 45 responden taken with purposive sampling technique. Statistical analysis using kolmogorov smirnov normality test was tested using the spearman correlation test. Data collection of zinc, magnesium, and fiber intake using the 2x24 hour recall and FFQ form while the blood sugar level data is obtained from the patient’s medical record book. The result showed that there was a relationship between zinc intake to fasting sugar levels of patients (p=0,000), there was a correlation between magnesium intake to fasting blood sugar levels in patients (p=0,000). There is a relationship between zinc, magnesium, and fiber intake to fasting blood sugar levels. Keywords: Zink Intake, Magnesium Intake, Fiber Intake, Fasting Blood Sugar Level, Type 2 Diabetes Mellitus

Flexible and lightweight speckle noise suppression module based on generation of dynamic speckles with multimode fiber and macro fiber composite

We propose a flexible and lightweight laser speckle noise suppression module based on the combination of a multimode fiber (MMF) and a macro fiber composite (MFC). The mechanism underlying speckle suppression involves the time-averaging of dynamic speckles during the exposure time of a charge-coupled device, wherein the MFC causes MMF vibration via its fast and periodic stretching due to the piezoelectric effect. The most efficient speckle reduction condition is realized when the MMF is vibrating in a resonant mode under the application of the highest MFC driving voltage and a large MMF effective numerical aperture. We obtain a speckle contrast of 0.08 when this “most efficient” speckle reduction condition is used to illuminate a diffuser. Further, the image quality is improved when our module is applied in a projector, which makes the device a flexible and lightweight module for speckle reduction in laser displays.

Experiment and Modeling on Macro Fiber Composite Stress-Induced Actuation Function Degradation

The effect of stress depolarization will cause actuation function degradation of a piezoelectric actuator, which can eventually trigger function failure of the piezoelectric smart structure system. In the present study, we experimentally demonstrate the degradation process of the actuation function of the Macro Fiber Composite (MFC) piezoelectric actuator. Actuation function degradation data of MFC actuators undergoing cyclic loads with four different stress amplitudes have been measured. Based upon the experimental results, the radial basis function (RBF) neural network learning algorithm was adopted to establish a neural network model, in order to predict the actuation function degenerative degree of the MFC actuator, undergoing arbitrary cyclic load within the concerned stress amplitude range. The maximum relative error between the predicted result and our experimental result is 4%.

Applications of piezoelectric MFC type transducers in mechatronic measurement systems - the impact of a mechanical subsystem damage on a system operation

The work include a report of research works concerning applications of non-classical piezoelectric transducers in mechatronic measuring systems. Composite piezoelectric transducers called Macro Fiber Composite (MFC) are considered. Characteristics of considered transducers were made, indicating their advantages and disadvantages, as well as the results of carried out laboratory tests are presented, in which MFC transducers were used as sensors for mechatronic measurement systems. A series of laboratory tests was carried out on the created laboratory stand to determine the impact on the measured values of damage of the mechanical subsystem on which the MFC-type piezoelectric transducer was glued. Results of measurements are presented and analysed in relation to different applications of the piezoelectric MFC sensors.

Nonlinear dynamics and dynamic instability of smart structural cross-ply laminated cantilever plates with MFC layer using zigzag theory

In this paper, a novel dynamic model for smart structural systems cross-ply laminated cantilever plate with smart material Macro fiber composites (MFC) layer is presented by using zigzag function theory. The nonlinear dynamic response and dynamic instability of the smart structural systems are studied for the first time. The plate is subjected to the uniformed static and in-plane harmonic excitation conjunction with electrically loaded under different electric boundary conditions. The partial layer-wise theory which the first shear deformation theory is expanded by introducing the zigzag function in the in-plane displacement components is adopted. The carbon fiber reinforced composite material T800/M21and macro fiber composites (MFC-d31) M8528-P3 are implemented. By Lagrangian equation and Chebyshev polynomial, the equations of motion are derived for the laminated plate. The validation and convergence are studied by comparing results with literatures. The dynamic instability regions and the critical buckling load characteristics can be obtained for different layer sequences, geometric dimensions and also the electromechanical effects are considered. Nonlinear dynamic responses of the laminated plate are studied by using numerical calculation. It can be seen that in certain state the plate will loses stability and the periodic, multiple period as well as chaotic motions of the plate are found.

Underwater oscillation performance and 3D vortex distribution generated by miniature caudal fin-like propulsion with macro fiber composite actuation

Underwater biomimetic propulsion systems that mimic the BCF (Body and/or Caudal Fin) fishes have attracted considerable attention. A miniature caudal fin-like propulsion device, whose design is based on the morphology and kinematics of the koi fish, is proposed in this paper. The propulsion is actuated by flexible fiber-based piezoelectric actuators, Macro Fiber Composite (MFC). A vacuum fabrication procedure is employed to bond the components of the proposed device. The underwater oscillation performances of the proposed propulsion at different steady-state sinusoidal excitations are experimentally investigated. Computational fluid dynamic (CFD) analysis is conducted to investigate the three-dimensional flow generated by the oscillation propulsion system. A simplified model, where the internal bending moment provided by the MFC actuators is replaced by a shear force, is created based on the obtained experimental data. The CFD simulations demonstrate that the maximum instantaneous and mean thrusts generated by the propulsion system during the stable period are 21.5 and 9.5 mN, respectively. These are consistent with the Lighthill’s elongated-body theory. Then, the uneven spatial distributions of the instantaneous vorticity around the propulsion are visualized, using seven two-dimensional planes intersecting at various locations. The CFD results suggest that the vorticity distributions around the trailing and leading edges of the caudal fin considerably differ because of the fin’s unique shape. A reverse Karman vortex street pattern is observed behind the trailing edge of the caudal fin. This indicates a thrust-producing pattern. On the other hand, a Karman vortex street pattern is distinctly observed before the leading edge. This indicates a drag-producing pattern. The geometry and shape effects of the caudal fin-like propulsion device are identified consequently. Those obtain results may be beneficial for the design of underwater vehicles with oscillation fin-like propulsion system.

Macro polypropylene fiber influences on crack geometry and water permeability of concrete

In order to study the effect of macro polypropylene fiber on crack geometry (tortuosity, surface roughness) and water permeability of concrete, the independently designed laser scanner was adopted to obtain the surface coordinates of the crack, the coefficients of crack tortuosity and surface roughness were introduced and the crack tortuosity and surface roughness were evaluated quantitatively through the MATLAB programming, the crack geometry of the specimens reinforced with macro polypropylene fibers and specimens without any reinforcement were compared. A self-designed device was adopted to the water permeability test, the influence of macro polypropylene fibers on water permeability of cracked concrete was studied. The Poiseuille law was modified regarding to the tortuosity factor and surface roughness factor. The results showed that: the coefficients of variation of the tortuosity factor and surface roughness factor were relatively small for all kinds of samples and could be used to verify the crack geometry of concrete. The crack geometry of the concrete was affected by the macro polypropylene fiber and the tortuosity and surface roughness of the crack increased with the increasing of fiber dosage. The modified Poiseuille law could be adopted to predict the water permeability of the cracked concrete.

A novel passive mechanism to improve power output in 2DOF piezoelectric vibration energy harvester

Cantilevered piezoelectric vibration energy harvesters are usually operated in the first mode and analysed as single degree of freedom (SDOF) systems. To improve their performance, a two degree of freedom (2DOF) system with a novel dynamic magnifier is developed by combining four bar mechanism and helical spring to act as elastic magnifier. This dynamic magnifier is attached between the base (excitation location) and the fixed end of cantilevered elastic harvester beam. To identify a suitable configuration for the dynamic magnifier, simulations are performed with two different configurations of passive mechanism, viz., 1:2 and 1:1 magnification four bar mechanisms. The natural frequencies of the first two modes obtained with 1:1 magnification four bar mechanism are close, giving good bandwidth and the mechanism is fabricated according to the simulation results. The simulated relative displacements and first two modal frequencies are in good agreement with experiments. There after macro fiber composite (MFC) with copper as substructure is used to fabricate the harvester beam within the required operating frequency range. The improvement in measured output power from 2DOF harvester over SDOF harvester is found to be 110% in the first mode and 270% in the second mode. Further, bandwidth analysis and effect of increase in magnifier mass is also investigated and performance characteristics of proposed 2DOF harvester are compared with the earlier similar harvesters. This kind of harvester with a novel four bar mechanism as a dynamic magnifier has not been reported in literature.

Active multimode vibration control of a smart structure using macro fiber composite actuators based on ANFIS

In this study, vibration control was achieved using macro fiber composite actuators initiated by feedback from polyvinylidene difluoride (PVDF) membrane sensors. First, the structure mode was found using the finite element method after which simulation of the effect of piezoelectric actuators on the structure as well as a feasibility investigation was carried out. The ANSYS Workbench was used for parametric design and to determine the best position for the actuators. Structure vibration in different modes was measured using PVDF membrane sensors for feedback control and to investigate the vibration reduction effect achieved with three individual controllers. The pros and cons of active vibration reduction control were also examined in several different modes. The experimental results obtained with several types of vibration reduction control were compared: Type-1 fuzzy control, Type-1 adaptive fuzzy control, and the vibration reduction effect of an adaptive neuro-fuzzy inference system. The results showed that the adaptive neuro-fuzzy inference system controller was the best choice under the experimental conditions used in this study.

Experimental study on underwater fin-shaped piezoelectric energy harvester based on wake galloping

This paper presents a novel piezoelectric energy harvester based on wake galloping in water. This harvester consists of a bluff cylinder and a fin connected with a macro fiber composite (MFC) piezoelectric plate. The fluid flows through the upstream bluff cylinder and produces alternating shedding vortices behind it. Vortex shedding produces periodic crosswise vortex-induced force to drive the fin and piezoelectric plate vibrating to generate electricity. An experimental platform was established and several prototypes of energy harvesters were fabricated. The experimental results show that, under different flow velocity domains, the harvesting effect of the bluff cylinder with a diameter of 30 mm is the most ideal for the energy harvester with a fin length of 20, 30 and 40 mm. When the fin length is 20 mm, the output voltage changes most smoothly. To obtain stable open circuit output voltage, the spacing distance between the bluff cylinder with a diameter of 25 mm and the fin should be controlled within 3D, while, the spacing distance between the bluff cylinder with a diameter of 30 mm and the fin should be controlled within 2D. When the bluff cylinder with a diameter of 30 mm, a spacing distance of 100 mm, and a flow velocity of 0.427 m/s, the maximum open circuit output voltage of 7.289 V can be obtained. The present work provides an effective experimental foundation for the research of underwater fin-shaped vehicle’s dynamic endurance.

Analysis on smart material suitable for autogenous microelectronic application

Microelectronic technology has possibly reduced the power consumption rate of portable electronic devices and has led to harvest its energy from the environment through Piezoelectric Energy Harvesting Systems (PEHS). The PEHS remains promising sources for the development of self-powered microelectronic applications. This literature discusses the PEHS for powering microelectronic applications with improved efficiency and also briefly reviews the different piezoelectric material which is best suitable for the PEHS’s. To validate the best piezoelectric material, an extensive experimental study has been carried out using the piezo materials such as; Lead Zirconate Titanate, Macro Fibre Composites, Quick Pack and Polyvinyl di-Fluoride in terms of vibrating frequencies, tip mass, and load resistance. The experimental results helps to understand the capability of the piezoelectric materials for energy generation when subjected to different stress and strain. The outcome of the experimental aids to choose the best piezoelectric material for the PEHS to power microelectronic applications.

The synergism of peak to peak value, frequency and superimposed DC bias voltage on electric-field-induced strain of PZT based-macro fiber composites

The macro fiber composites (MFCs) with uniform and repeatable electromechanical performance have been a popular choice in various applications like structural actuation, vibration control, structural health monitoring, and energy harvesting. Herein, the strains of lead zirconate titanate based MFCs subjected to various driving signals were conducted via the strain-electrometry method. The formation mechanism of the strains was profoundly expounded, and the variation of the strains as a function of peak to peak value, frequency and superimposed DC bias voltage was further explored. The results demonstrate that both longitudinal and transverse strain-voltage curves with the voltage cyclic loading are closed “ellipse-like” hysteresis loops, in which the strain of ascending branch is smaller than that of the descending branch. Both strains increase with increasing the peak to peak value of driving signal and the increase is more remarkable at smaller bias voltage and lower frequency, while decrease with increasing the positive DC bias voltage and the decrease is specially obvious at larger peak to peak value and lower frequency. Besides, the dispersive effect of the strains induced by larger peak to peak value, particularly with smaller superimposed bias voltage, is more apparent than that induced by smaller peak to peak value. The longitudinal and transverse strains of MFCs with an active area of 40 mm × 30 mm range from 74.8 με to 1688.3 με, and 20.3 με to 488 με, respectively. This research indicates that through properly and carefully synthetical modulation of electrical parameters of driving signal, a notably enhanced strain can be achieved in MFCs for the specific applications such as actuation and high frequency structural control.

Modeling on Actuation Behavior of Macro-Fiber Composite Laminated Structures Based on Sinusoidal Shear Deformation Theory

A new piezoelectric composite, macro fiber composite (MFC) is recombined with piezoceramic fibers, an epoxy resin basal body, and an interdigitated electrode. It has been widely applied in vibration reduction and deformation control of thin-walled structures, due to its great deformability and flexibility. Research on its actuation performance is mostly concentrated on the MFC actuating force calculation based on classical plate theory (CPT), and the overall modeling of MFC and its structure. However, they have some deficiencies in the tedious calculating process and neglect of shear deformation, respectively. To obtain a precise MFC actuating force, the sinusoidal shear deformation theory (SSDT) is adopted to deduce the MFC actuating force formula, and global–local displacement distribution functions are introduced to help the MFC laminated plate structure satisfy the deformation compatibility and stress balance. For instance, in the end displacement calculation of the MFC laminated beam structure. The experimental result of the MFC laminated beam is compared with those of the MFC actuating force based on SSDT and on CPT, which indicates that the MFC actuating force formula based on SSDT can reach higher computational accuracy.

Macro fiber composite-based energy harvester for human knee

The harvesting of energy from human motion for portable and wearable electronic devices has received considerable attention. This letter describes a lightweight macrofiber composite (MFC)-based energy harvester for capturing biomechanical energy through the natural motion of the human knee. In the proposed device, a slider-crank mechanism is used to transform the rotary motion of the knee joint to linear motion, and a bending beam is used to transform the linear motion to a bending motion. When walking, a bending deformation is induced in two MFC slices attached to the bending beam, generating electrical energy. To test the performance of the developed device, treadmill tests at various walking speeds and resistive loads are performed. Experimental results show that the lightweight harvester (weighing just 307 g) can generate 1.60 mW without increasing the human effort required for walking. This is expected to significantly promote the usage of biomechanical energy harvesters.

Piezoelectric energy harvesting based on macro fiber composite from a rotating shaft

Piezoelectric energy harvesting from rotating applications can be realized by the use of harvesters, the basic part of which is a piezoelectric material. Such harvesters have various structures but most of them contain a cantilever composite beam, which consists of the carrying material and the piezoelectric material. A diversification of the harvester structures is, above all, the result of the application of additional mechanical structures, the task of which is to deform the cantilever composite beam. In contrast to these approaches, this article presents the simulation and laboratory investigation of the piezoelectric energy harvesting from a rotating shaft without the use of any additional mechanical structure. Energy harvesting was realized by the use of macro fiber composite (MFC), which was directly glued onto the rotating shaft surface, instead of on a cantilever beam being a part of the additional mechanical structure. In the theoretical part of the article, a mathematical model of piezoelectric energy harvesting from the rotating shaft with the use of MFC was elaborated. This model was verified on the basis of the laboratory experiments. On the basis of the simulation and laboratory experiments it was found that both an increase in the rotation frequency of the shaft and an increase in the stress in a rotating shaft caused a linear increase in the voltage generated by the MFC and caused an exponential increase in power generated by the MFC. These characteristics are significantly different to the characteristics obtained for harvesters consisting of a cantilever beam, in which the maximal value of a voltage and a power is generated only for a resonant frequency of a cantilever beam. In spite of these differences the optimal load resistance for the specific rotation frequency of the shaft can be calculated from the formula used to calculate the optimal load resistance for a harvester based on a cantilever beam.

Simulation Analysis of Bionic Robot Fish Based on MFC Materials

With the development of marine resources, research on underwater robots has received unprecedented attention. The discovery and application of new smart materials provide new ideas for the research of underwater robots, which can overcome the issues of traditional underwater robots and optimize their design. A macro fiber composite (MFC) is a new type of piezoelectric fiber composite that combines actuators and sensors. The material has excellent deflection, good flexibility, and a high electromechanical coupling coefficient. Bionic mechatronics design is an effective way to innovate mechatronics in the future and can significantly improve mechatronics system performance. As an important issue for the design of bionic mechatronics, it is necessary to make robots as soft as natural organisms to achieve similar biological movement with both higher efficiency and performance. Compared with traditional rigid robots, the design and control of a soft robotic fish are difficult because the coupling between the flexible structure and the surrounding environment should be considered, which is difficult to solve due to the large deformation and coupling dynamics. In this paper, an MFC smart material is applied as an actuator in the design of bionic robotic fish. Combined with the piezoelectric constitutive and elastic constitutive equations of the MFC material, the voltage-drive signal is converted to a mechanical load applied to the MFC actuator, which makes the MFC material deform and drives the movement of the robotic fish. The characteristics of caudal fin motion during the swimming process of the bionic robotic fish were analyzed by an acoustic-solid coupling analysis method. The motion control analysis of the bionic robotic fish was carried out by changing the applied driving signal. Through numerical analysis, a new type of soft robotic fish was designed, and the feasibility of using an MFC smart material for underwater bionic robotic fish actuators was verified. The new soft robotic fish was successfully developed to achieve high performance.

Internal Resonance Responses of Rectangular Cross-Ply Composite Plates with Graphene Skins

This paper presents an investigation on the nonlinear dynamic behavior of three-phase rectangular composite plates made of cross-ply macro fiber composites (MFC) in the polymer with graphene (GP) skins, which are uniformly dispersed at the top and bottom surfaces of the plates. According to the mixture rules for multi-components of composite materials, the constitutive laws for MFC-GP composite materials can be obtained. A simply-supported rectangular plate model subjected to a transversal excitation in thermal environments is considered. The governing equations are formulated by using the first-order shear deformation theory, von Kármán geometrical kinematics and Hamilton’s principle. The Galerkin approach is used to discretize the governing equations for analysis. The vibration frequencies of MFC-GP composite plates with different modes are presented and the case of 1:2 internal resonance is selected to be investigated here. Three different coupled forms (i.e. uncoupled, weakly coupled and strongly coupled cases) of two vibration modes are presented. In addition, the influences of various parameters, including volume fraction of graphene, applied voltage, temperature effect and external excitation, on the nonlinear dynamic characteristics of MFC-GP composite plates are also examined.