Showing papers on "Piezoelectric sensor published in 2018"

Biodegradable Piezoelectric Force Sensor.

Abstract: Measuring vital physiological pressures is important for monitoring health status, preventing the buildup of dangerous internal forces in impaired organs, and enabling novel approaches of using mechanical stimulation for tissue regeneration. Pressure sensors are often required to be implanted and directly integrated with native soft biological systems. Therefore, the devices should be flexible and at the same time biodegradable to avoid invasive removal surgery that can damage directly interfaced tissues. Despite recent achievements in degradable electronic devices, there is still a tremendous need to develop a force sensor which only relies on safe medical materials and requires no complex fabrication process to provide accurate information on important biophysiological forces. Here, we present a strategy for material processing, electromechanical analysis, device fabrication, and assessment of a piezoelectric Poly-l-lactide (PLLA) polymer to create a biodegradable, biocompatible piezoelectric force sensor, which only employs medical materials used commonly in Food and Drug Administration-approved implants, for the monitoring of biological forces. We show the sensor can precisely measure pressures in a wide range of 0–18 kPa and sustain a reliable performance for a period of 4 d in an aqueous environment. We also demonstrate this PLLA piezoelectric sensor can be implanted inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction. This piezoelectric sensor offers an appealing alternative to present biodegradable electronic devices for the monitoring of intraorgan pressures. The sensor can be integrated with tissues and organs, forming self-sensing bionic systems to enable many exciting applications in regenerative medicine, drug delivery, and medical devices.

Phase-Separation-Induced PVDF/Graphene Coating on Fabrics toward Flexible Piezoelectric Sensors.

Abstract: Clothing-integrated piezoelectric sensors possess great potential for future wearable electronics. In this paper, we reported a phase-separation approach to fabricate flexible piezoelectric sensors...

Preload Monitoring in Bolted Connection Using Piezoelectric-Based Smart Interface

Abstract: In this study, a preload monitoring method using impedance signatures obtained from a piezoelectric-based smart interface is presented for bolted girder connections. Firstly, the background theory of the piezoelectric-based smart interface and its implementation into the health monitoring of bolted connections are outlined. A simplified electro-mechanical (EM) impedance model of a smart interface-embedded bolted connection system is formulated to interpret a mechanistic understanding of the EM impedance signatures under the effect of bolt preload. Secondly, finite element modeling of a bolted connection is carried out to show the numerical feasibility of the presented method, and to predetermine the sensitive frequency band of the impedance signatures. Finally, impedance measurements are conducted on a lab-scaled bolted girder connection, to verify the predetermined sensitive frequency range and to assess the bolt preload changes in the test structure.

Kirigami stretchable strain sensors with enhanced piezoelectricity induced by topological electrodes

Abstract: Rapid advances in sensing technologies are leading to the development of integrated wearable electronics for biomedical applications. Piezoelectric materials have great potential for implantable devices because of their self-powered sensing capacities. The soft and highly deformable surfaces of most tissues in the human body, however, restrict the wide use of piezoelectric materials, which feature low stretchability. Flexible piezoelectric polyvinylidene fluoride films that could conformably integrate with human bodies would have advantages in health monitoring. Here, a Kirigami technique with linear cut patterns has been employed to design a stretchable piezoelectric sensor with enhanced piezoelectricity. A parametric Finite Element Analysis study is first performed to investigate its mechanical behaviour, followed by experiments. An inter-segment electrode connection approach is proposed to further enhance the piezoelectric performance of the sensor. The voltage output shows superior performance with 2.6 times improvement compared to conventionally continuous electrodes. Dynamic tests with a range of frequencies and strains are performed to validate the sensor design. With its high performance in large strain measurements, the Kirigami-based sensing system shows promise in stretchable electronics for biomedical devices.

Mechanical characterization of 3D printed anisotropic cementitious material by the electromechanical transducer

Abstract: 3D concrete printing is an innovative and promising construction method that is rapidly gaining ground in recent years. This technique extrudes premixed concrete materials through a nozzle to build structural components layer upon layer without formworks. The build-up process of depositing filaments or layers intrinsically produce laminated structures and create weak joints between adjacent layers. It is of great significance to clearly elaborate the mechanical characteristics of 3D printed components response to various applied loads and the different performance from the mould-cast ones. In this study, a self-developed 3D printing system was invented and applied to fabricate concrete samples. Three points bending test and direct double shear test were carried out to investigate the mechanical properties of 3D printed prisms. The anisotropic behaviors were probed by loading in different directions. Meanwhile, piezoelectric lead zirconate titanate (PZT) transducers were implemented to monitor the damage evolution of the printed samples in the loading process based on the electromechanical impedance method. Test results demonstrate that the tensile stresses perpendicular to the weaken interfaces formed between filaments were prone to induce cracks than those parallel to the interfaces. The damages of concrete materials resulted in the decrease in the frequency and a change in the amplitude in the conductance spectrum acquired by mounted PZT patches. The admittance signatures showed a clear gradation of the examined damage levels of printed prisms exposed to applied loadings.

Review of high temperature piezoelectric materials, devices, and applications

Abstract: Piezoelectric functional materials have been extensively studied and employed in numerous devices. With the rapid development of modern industries, such as power plants, aerospace, automotive, renewable energy and material processing industries, the high temperature piezoelectric materials that can work in extreme environments are in great demand. Piezoelectric materials including piezoelectric single crystals, ceramics and films, are at the heart of electromechanical actuation and sensing devices. A variety of applications where piezoelectric actuators and sensors operate at elevated temperatures (T 200℃) would be extremely desired. The actuators need to work efficiently with high strokes, torques, and forces while operating under relatively harsh conditions. These include high-temperature fans and turbines, motors for valves or natural gas industries, kiln automation, and actuators for automotive engines such as fuel injectors and cooling system elements. Yet, the majority of industrial actuator applications are at or below the 250℃ temperature limit. In addition to the increase in operational temperatures of piezoelectric motors and actuators, a future area of interest is high-temperature MEMS research, which can be used for high-temperature valving. On the other hand, the piezoelectric sensors have been widely used for structural health monitoring applications. This is due to their wide bandwidth, versatility, simplicity, high rigidity, high stability, high reproducibility, fast response time, wide operating temperature range, insensitivity to electric and magnetic fields, the capacity for miniaturization and minimal dependence on moving parts and low power consumption, and wide piezoelectric materials and mechanisms selections, which will greatly benefit the sensing applications. In addition to the temperature usage range, the piezoelectric sensors must withstand the harsh environments encountered in space, engine, power plants, and also need to possess high sensitivity, resistivity, reliability, stability and robustness. In order to use the piezoelectric materials for a specific high temperature application, many aspects need to be considered together with piezoelectric properties, such as phase transition, thermal aging, thermal expansion, chemical stability, electrical resistivity, and the stability of properties at elevated temperature. In this paper, ferroelectric materials with high Curie point, including perovskite-type ferroelectrics, bismuth layer structured ferroelectrics, tungsten-bronze structured ferroelectrics, together with non-ferroelectric piezoelectric single crystals, are surveyed. The crystal structure characteristics, high temperature piezoelectric properties, and recent research progress are discussed. A series of high temperature piezoelectric devices and their applications are reviewed, including high temperature piezoelectric detectors, sensors, transducers, actuators, etc. Finally, recent important research topics, the future development of high temperature piezoelectric materials and the potential new applications are summarized.

High sensitivity detection of partial discharge acoustic emission within power transformer by sagnac fiber optic sensor

Abstract: Partial discharge acoustic detection is an important monitoring tool for power transformer diagnosis, which was traditionally performed by mounting the piezoelectric transducers on the oil tank surface. The disadvantage of partial discharge acoustic detection is its low sensitivity when partial discharge occurs inside the winding, which greatly compromises the value of partial discharge acoustic detection. Fiber optic sensors that can be deployed within power transformer are expected to be a potential solution. In this research, we used a Sagnac fiber sensor system built in lab to investigate the benefits of using fiber optic sensor for partial discharge acoustic detection. Acoustic pulses were induced in oil outside the winding and in oil duct inside the winding of a single phase 50 kV transformer. Although both fiber optic sensor and piezoelectric sensor can effectively detect the acoustic pulses outside the winding, fiber optic sensor gained a much better sensitivity over piezoelectric transducer to detect the acoustic pulses originated inside the winding. We envisage that the proposed fiber sensor can be deployed in power transformers to significantly enhance the detection performance of acoustic emission induced by partial discharge.

Impact Monitoring for Aircraft Smart Composite Skins Based on a Lightweight Sensor Network and Characteristic Digital Sequences.

Abstract: Due to the growing use of composite materials in aircraft structures, Aircraft Smart Composite Skins (ASCSs) which have the capability of impact monitoring for large-scale composite structures need to be developed. However, the impact of an aircraft composite structure is a random transient event that needs to be monitored on-line continuously. Therefore, the sensor network of an ASCS and the corresponding impact monitoring system which needs to be installed on the aircraft as an on-board device must meet the requirements of light weight, low power consumption and high reliability. To achieve this point, an Impact Region Monitor (IRM) based on piezoelectric sensors and guided wave has been proposed and developed. It converts the impact response signals output from piezoelectric sensors into Characteristic Digital Sequences (CDSs), and then uses a simple but efficient impact region localization algorithm to achieve impact monitoring with light weight and low power consumption. However, due to the large number of sensors of ASCS, the realization of lightweight sensor network is still a key problem to realize an applicable ASCS for on-line and continuous impact monitoring. In this paper, three kinds of lightweight piezoelectric sensor networks including continuous series sensor network, continuous parallel sensor network and continuous heterogeneous sensor network are proposed. They can greatly reduce the lead wires of the piezoelectric sensors of ASCS and they can also greatly reduce the monitoring channels of the IRM. Furthermore, the impact region localization methods, which are based on the CDSs and the lightweight sensor networks, are proposed as well so that the lightweight sensor networks can be applied to on-line and continuous impact monitoring of ASCS with a large number of piezoelectric sensors. The lightweight piezoelectric sensor networks and the corresponding impact region localization methods are validated on the composite wing box of an unmanned aerial vehicle. The accuracy rate of impact region localization is higher than 92%.

A PVDF-Based Sensor for Internal Stress Monitoring of a Concrete-Filled Steel Tubular (CFST) Column Subject to Impact Loads.

Abstract: Impact loads can have major adverse effects on the safety of civil engineering structures, such as concrete-filled steel tubular (CFST) columns. The study of mechanical behavior and stress analysis of CFST columns under impact loads is very important to ensure their safety against such loads. At present, the internal stress monitoring of the concrete cores CFST columns under impact loads is still a very challenging subject. In this paper, a PVDF (Polyvinylidene Fluoride) piezoelectric smart sensor was developed and successfully applied to the monitoring of the internal stress of the concrete core of a CFST column under impact loads. The smart sensor consists of a PVDF piezoelectric film sandwiched between two thin steel plates through epoxy. The protection not only prevents the PVDF film from impact damages but also ensures insulation and waterproofing. The smart sensors were embedded into the circular concrete-filled steel tube specimen during concrete pouring. The specimen was tested against impact loads, and testing data were collected. The time history of the stress obtained from the PVDF smart sensor revealed the evolution of core concrete internal stress under impact loads when compared with the impact force–time curve of the hammer. Nonlinear finite element simulations of the impact process were also carried out. The results of FEM simulations had good agreement with the test results. The results showed that the proposed PVDF piezoelectric smart sensors can effectively monitor the internal stress of concrete-filled steel tubular columns under impact loads.

Flexible Capacitive Piezoelectric Sensor with Vertically Aligned Ultralong GaN Wires.

Abstract: We report a simple and scalable fabrication process of flexible capacitive piezoelectric sensors using vertically aligned gallium nitride (GaN) wires as well as their physical principles of operation. The as-grown N-polar GaN wires obtained by self-catalyst metal–organic vapor phase epitaxy are embedded into a polydimethylsiloxane (PDMS) matrix and directly peeled off from the sapphire substrate before metallic electrode contacting. This geometry provides an efficient control of the wire orientation and an additive contribution of the individual piezoelectric signals. The device output voltage and efficiency are studied by finite element calculations for compression mechanical loading as a function of the wire geometrical growth parameters (length and density). We demonstrate that the voltage output level and sensitivity increases as a function of the wire length and that a conical shape is not mandatory for potential generation as it was the case for horizontally assembled devices. The optimal design to ...

A Novel Waveform Optimization Scheme for Piezoelectric Sensors Wire-Free Charging in the Tightly Insulated Environment

Abstract: Sustainable powering of wire-free sensors (WFSs) is a critical challenge in structure health monitoring for failure prevention applications, where battery replacement is practically difficult. Hence, it is of interest to develop means for remotely charging WFS devices using external power sources. In this paper, a novel stress wave-based optimization method is proposed for piezoelectric sensors wire-free charging. This method includes a novel waveform optimization scheme, a novel multiactuator, and a multichannel wire-free charging strategy to maximize energy transmission efficiency. Based on the measured channel characteristics of a tightly insulated environment, four different waveform design algorithms are implemented successfully to generate the optimized charging waveforms in accordance with the novel waveform optimization scheme. To testify the effectiveness of this novel optimized wire-free charging method, the piezoelectric sensor-based wire-free charging process is simulated. In the simulation process, a predefined waveform is applied in the piezoelectric actuator to generate a stress wave which is subsequently utilized to wire-free transfer energy to the piezoelectric sensors. Numerical results demonstrate the advantages of multichannel wire-free charging in significantly reducing input power loss and enhancing energy transmission efficiency.

Broadband Calibration of Acoustic Emission and Ultrasonic Sensors from Generalized Ray Theory and Finite Element Models

Abstract: This paper describes a calibration method for acoustic emission and ultrasonic sensors that is effective from 1 kHz to 1 MHz. The method combines generalized ray theory and finite element analysis to model wave propagation at higher and lower frequencies, respectively. A ball impact is used as a calibration source, a thick aluminum plate is used as the test block, and hot glue is used as the couplant. We demonstrate this method on five commercial piezoelectric sensors: Physical Acoustics (PAC) R15a, PAC WSa, Panametrics V101, Panametrics V103, and Valpey-Fisher Pinducer. Our calibration results show that reflections and other wave phases can be more clearly identified with the less-resonant Panametrics sensors. The PAC sensors have the greatest sensitivity and are able to detect surface normal displacements at least down to 1 pm amplitude in the 100s of kHz frequency band. Aperture effect is minimized by the small size of the Pinducer. Our method focuses on the amplitude response of the sensors (phase is ignored) and extends the calibration to a frequency band that is lower than typical analyses. Low frequency information is useful for determining the seismic moment of a seismic source (analogous to the magnitude of an earthquake) and can increase the amount of information acquired in a single recording.

PZT/PZT and PZT/BIT composite piezo-sensors in aerospace SHM applications: Photochemical metal organic + infiltration deposition and characterization

Abstract: The composition of fine-ground lead zirconate-titanate powder Pb(Zr0.52Ti0.48)O₃, suspended in PZT and bismuth titanate (BiT) solutions, is deposited on the curved surface of IN718 and IN738 nickel-based supper alloy substrates up to 100 µm thickness. Photochemical metal organic and infiltration techniques are implemented to produce smooth, semi-dense, and crack-free random orientated thick piezoelectric films as piezo-sensors, free of any dopants or thickening polymers. Every single layer of the deposited films is heated at 200 °C with 10 wt.% excess PbO, irradiated by ultraviolet lamp (365 nm, 6 watt) for 10 min, pyrolyzed at 400 °C, and subsequently annealed at 700 °C for one hour. This process is repeated successively until reaching the desired thickness. Au and Pt thin films are deposited as the bottom and top electrodes using evaporation and sputtering methods, respectively. PZT/PZT and PZT/BiT composite films are then characterized and compared to similar PZT and BiT thick films deposited on the similar substrates. The effect of the composition and deposition process is also investigated on the crystalline phase development and microstructure morphology as well as the dielectric, ferroelectric, and piezoelectric properties of piezo-films. The maximum remnant polarization of Pr = 22.37 ± 0.01, 30.01 ± 0.01 µC/cm², the permittivity of er = 298 ± 3, 566 ± 5, and piezoelectric charge coefficient of d33 = 126, 148 m/V were measured versus the minimum coercive field of Ec = 50, 20 kV/cm for the PZT/PZT and PZT/BiT thick films, respectively. The thick film piezo-sensors are developed to be potentially used at frequency bandwidth of 1⁻5 MHz for rotary structural health monitoring and also in other industrial or medical applications as a transceiver.

Miniature Piezoelectric Sensor for In-Situ Temperature Monitoring of Silicon and Silicon Carbide Power Modules Operating at High Temperature

Abstract: Owing to the introduction of wide-bandgap power devices, recent power modules operate at higher temperatures. This increased module temperature leads to significant reliability problems, which render thermal monitoring very important. Several thermal sensors have been used in power modules; however, each of these sensors has drawbacks such as limited maximum temperature, nonlinearity, power source requirement, or limited miniaturization. This paper proposes a new temperature sensor that utilizes the piezoelectric effect. A new piezoelectric material (PZT-PZNM) with a high Curie temperature (260 °C) is soldered onto a direct bonded copper substrate. When the power module is operating at a high temperature, the substrate deflects and induces thermal stress, which is converted into an electric voltage via a piezoelectric mechanism. The voltage can be maximized by optimizing the location of the PZT-PZNM; the best location was determined to be away from the power devices. This observation confirms that the piezoelectric temperature sensor has a negligible influence on the performance of the power devices. Moreover, the sensor volume was miniaturized (approximately 74% reduction compared with preliminary work) to ensure that it can be readily integrated into power modules. The developed piezoelectric sensor demonstrates excellent linearity ( R 2 = 0.99, approximately) up to 250 °C, which is sufficient for monitoring temperature in both silicon and silicon carbide power modules.

A high-sensitive current-mode pressure/force detector based on piezoelectric polymer PVDF

Abstract: This paper introduces new electronic sensor circuits based on the usage of a piezoelectric Polyvinylidene fluoride-PVDF pressure detector coupled with a current-mode instrumentation amplifier, Schmitt comparator, and only grounded resistors. Pressure/force is measured in terms of the charge generated by the PVDF element as a result of the direct piezoelectric effect. The experimental test results demonstrated that the dynamic pressure response, the sensitivity and linearity of the designed sensor were higher than the sensitivity and linearity of a traditional piezoelectric sensor. The sensitivity of the PVDF sensor was 0.08 mV/Pa. The detector is calibrated over a frequency range of 1 Hz–1 kHz. The proposed signal conditioning electronics offer a potential for future miniaturization in order to be integrated with different commercial devices, for detecting certain tiny activities including finger movements, robotics and smart electronic devices.

New Methodology for Optimal Placement of Piezoelectric Sensor/Actuator Pairs for Active Vibration Control of Flexible Structures

Abstract: This paper describes a computationally efficient method to determine optimal locations of sensor/actuator (s/a) pairs for active vibration reduction of a flexible structure. Previous studies have tackled this problem using heuristic optimization techniques achieved with numerous combinations of s/a locations and converging on a suboptimal or optimal solution after multithousands of generations. This is computationally expensive and directly proportional to the number of sensors, actuators, possible locations on structures, and the number of modes required to be suppressed (control variables). The current work takes a simplified approach of modeling a structure with sensors at all locations, subjecting it to external excitation force or structure base excitation in various modes of interest and noting the locations of n sensors giving the largest average percentage sensor effectiveness. The percentage sensor effectiveness is measured by dividing all sensor output voltage over the maximum for each mode using time and frequency domain analysis. The methodology was implemented for dynamically symmetric and asymmetric structures under external force and structure base excitations to find the optimal distribution based on time and frequency responses analysis. It was found that the optimized sensor locations agreed well with the published results for a cantilever plate, while with very much reduced computational effort and higher effectiveness. Furthermore, it was found that collocated s/a pairs placed in these locations offered very effective active vibration reduction for the structure considered.

High Bending-Mode Sensitivity of Printed Piezoelectric Poly(vinylidenefluoride-co-trifluoroethylene) Sensors

Abstract: Printable piezoelectric sensors were fabricated on a flexible polyethylene terephthalate (PET) substrate. Solution-processed piezoelectric poly(vinylidenefluoride-co-trifluoroethylene) ink was used as an active layer. Evaporated silver on PET was used as the bottom electrode and the painted silver glue as the top electrode. The sensors were poled using a high dc electric field from 25 to 65 MV m-1, yielding piezoelectric normal direction sensitivities up to 25 pC N-1. Bending-mode sensitivities showed values up to 200 nC N-1, which is 4 orders of magnitude larger than the force sensitivity in the normal direction. The high bending-mode sensitivities suggest suitability for detecting small forces, such as single fiber bonds or cardiomyocyte cell-beating force.

Design and modeling of a novel high sensitive MEMS piezoelectric vector hydrophone

Abstract: In this paper, a novel micro electromechanical systems (MEMS) piezoelectric hydrophone with the ability to detect the direction of the sound in two dimensions was designed and analyzed. Piezoelectric hydrophones are widely used today. These devices constitute the main part of the sonar systems. Sonars are used in marine vessels and for transportation of marine military equipment, such as submarines and battleships. Hydrophones work by converting received sound pressure to electrical signals. The idea of the present paper for designing hydrophones is taken from sea creatures and use artificial hair cell structure. This structure not only has the advantages of piezoelectric sensors such as being active and having optimal sensitivity, but it is also able to detect the direction of the sound and work at low frequencies, the performance of the sensor has been improved compared with the previous works (Ito et al. in Sens Actuators, 2008; Choi et al. in Sens Actuators, 2010; Guan et al. in Microsyst Technol, 2011; Sens Actuators, 2012; Zhang et al. in Design of a monolithic integrated three-dimensional MEMS bionic vector hydrophone, 2014), in a way that its sensitivity is ź 191 dB in the frequency range of below 10.4 kHz (0 dB re 1 V/μPa).

Dressing Tool Condition Monitoring through Impedance-Based Sensors: Part 1-PZT Diaphragm Transducer Response and EMI Sensing Technique.

Abstract: Low-cost piezoelectric lead zirconate titanate (PZT) diaphragm transducers have attracted increasing attention as effective sensing devices, based on the electromechanical impedance (EMI) principle, for applications in many engineering sectors. Due to the considerable potential of PZT diaphragm transducers in terms of excellent electromechanical coupling properties, low implementation cost and wide-band frequency response, this technique provides a new alternative approach for tool condition monitoring in grinding processes competing with the conventional and expensive indirect sensor monitoring methods. This paper aims at assessing the structural changes caused by wear in single-point dressers during their lifetime, in order to ensure the reliable monitoring of the tool condition during dressing operations. Experimental dressing tests were conducted on aluminum oxide grinding wheels, which are highly relevant for industrial grinding processes. From the results obtained, it was verified that the dresser tip diamond material and the position of the PZT diaphragm transducer mounted on the dressing tool holder have a significant effect on the sensitivity of damage detection. This paper contributes to the realization of an effective monitoring system of dressing operations capable to avoid catastrophic tool failures as the proposed sensing approach can identify different stages of the dressing tool lifetime based on representative damage indices.

Highly Reliable Real-time Self-powered Vibration Sensor Based on Enhanced Piezoelectric Nanogenerator

Abstract: With the diverse development tendency of electronic devices, the sensors of battery supplied, high cost and low reliability have been severe obstacles to restrict the sensors' wide applications. Here, this paper presents a highly reliable real-time self-powered vibration sensor based on enhanced piezoelectric nanogenerator (NG), which possesses heat -resistant, waterproof, relatively low cost, and long lifetime. The enhanced piezoelectric NG is constructed into a double arched structure: the upper arched layer is the poly(vinylidene fluoride)(PVDF) film with designed optimum size which can obtain the excellent piezoelectric potential of the d31 mode; the lower arched layer is the PDMS film covered by the uniform trapezoid body micro-structures increasing the charge density of piezoelectric NG. The piezoelectric NG output voltage with the double arched structure could increase by 35.1% at the mechanical force of 5 N. Considering improved large and steady voltage output performance, the enhanced piezoelectric NG was used as the sensitive element of the sensor displaying the sensitivity of 2.21V/g and linearity error of 5.91% under the vibration amplitude of 6mm. Moreover, the sensor not only had stable repeatability and long term stability, but also achieved the capability to steadily produce output performances after soaking in water with temperature even up to 70 °C. Therefore, the highly reliable self-powered vibration sensor presents prominent prospect in future life.

Highly Sensitive Wearable Piezoelectric Force Sensor With Quasi-Static Load Testing

Abstract: This paper proposes the development of a wearable piezoelectric sensor from polyvinylidene fluoride (PVDF) that can be integrated into clothing and measure high forces. Based on the direct piezoelectric effect, good linearity is expected such that there should be an increase in voltage as higher loads are tested. With external circuitry and an interface to a computer via a microcontroller board, measurements include calculations for initial voltage, force, pressure, and normalized voltage as well as measured voltage. Results are analyzed based on two criteria: first, wearable conditions based on no-cloth, rigid-cloth, and smooth-cloth implementations; and second, the maximum force applied by varying sensor dimensions. Two load ranges were also applied: low-force threshold between 2.5 and 10 kN with steps of 0.5 kN and high-force threshold between 10 and 50 kN with steps of 2.5 kN. Given this criteria, all results that have shown great accuracy can be attained, since all percent errors are within the performance error threshold between 2% and 5%.