Maximum Electric Field Intensity Research Articles

Electromagnetic field simulation modeling method and distribution characteristics of electric vehicle wireless charging system

In recent years, wireless charging technology for electric vehicles has gained significant attention. To accurately analyze the distribution characteristics of the electromagnetic field during the wireless charging process of electric vehicles, a finite element-based electromagnetic analysis method was employed. Applied in the commercial simulation software, the electromagnetic environment of the resonant coil and electric vehicle model was simulated under high-power charging conditions, resulting in an overall electromagnetic field distribution for the electric vehicle. The results indicated that within the coil region, the magnetic induction intensity in the central area of the coil was zero, and it increased as the distance from the center of the coil grew. Outside the coil region, the magnetic induction intensity gradually decreased. The electric field intensity of the resonant coil was maximum in the central area of the coil, and it weakened as the distance from the center of the coil increased. When a magnetic shielding resonant coil was used, the electromagnetic field was confined between the shielding materials, and the magnetic field rapidly attenuated on both sides of the magnetic shield. The electromagnetic field energy of the electric vehicle body was mainly concentrated at the bottom of the vehicle near the coil. When the coil was located in the front of the car body, the maximum electric field intensity distribution in the car body was 8.50 V/m, and the maximum magnetic induction intensity was 0.024 μT. When the coil was located in the middle of the car body, the maximum electric field intensity was 2.31 V/m, the maximum magnetic induction intensity was 0.019 μT. As the distance from the coil position increased, the energy weakened.

Mechanism of lightning damage to glass fiber composite wind turbine blades

Wind turbine blades (WTBs) are susceptible to lightning damage, resulting in significant costs for repair and replacement, which poses a considerable economic burden on wind farms. Therefore, this study investigates the mechanism of lightning damage of glass fiber composite (GFC)-WTBs to reduce the risk of such damage. The damage of GFC-WTBs caused by lightning strikes was analyzed using a numerical simulation method. The lightning pilot was simulated using high-voltage rod electrodes, and subsequently, the electric field strength and damage area on the blade surface under different conditions were measured. Additionally, a simulation model based on finite element analysis was developed to further predict and validate the experimental findings. The results reveal that the maximum electric field intensity was observed in the blade tip. Notably, the electric field intensity was found to be over 798,000 V/m when the rod electrode was positioned at a 0-degree angle with the blade tip. Further investigation revealed a non-linear and positive correlation between the damage area of GFC and lightning current amplitude, charge, and specific energy. In conclusion, the study provides a comprehensive examination of the relationship between lightning current and the damage to GFC-WTBs, as well as elucidates the mechanism of lightning damage to GFC-WTBs.

Casting of nickel powder based MMC using microwave energy

In this paper, an experimental setup is developed to cast a metal matrix composite (MMC) specimen, by using microwave energy as a heat source. A MMC (Nickel and 15 % of SiC by weight percentage) specimen of size 140 × 30 × 2 mm3 is in-situ cast by using a domestic microwave applicator at 2.45 GHz frequency, and 900 W, power output. As per selected process parameters, the exposure time to cast MMC specimen, inside an electromagnetic environment is optimized as 33 min. A COMSOL Multiphysics software tool is also used to model the in-situ microwave-assisted casting setup. Numerical simulations are performed to visualize the microwave heating effects within the applicator cavity. Microwave heating effects are analyzed in terms of electric field distribution, resistive heating and temperature profile. As per the simulation study results, maximum electric field intensity (4.46 × 104 (V/m)) is observed around the mold. Resistive heating losses are maximum (4 .9× 109 W/m3) in the susceptor zone. It is observed from the simulation study, that uniform heating of the specimen is observed throughout the cross-section and the melting temperature of the specimen is achieved in 38 min. A good correlation is observed between experimental and simulation study results in terms of exposure time of cast specimen and microwave heating effects within the applicator cavity

Three-Dimensional Transient Electric Field Characteristics of High Pressure Electrode Boilers

An uneven electric field during the operation of an electrode boiler will lead to the emergence of a high field strength area and low field strength area in the furnace, which will endanger the safe and reliable operation and heating efficiency of the electrode boiler. A numerical study of three-dimensional transient electric field distribution characteristics in a 10 kV high-voltage electrode boiler was carried out. The distribution characteristics of the global electric field of the electrode boiler under the nominal voltage of 10 kV were studied, and the distribution law of the electric field of the electrode boiler under poor power quality, such as different bus voltage and three-phase voltage imbalance, was explored. The results show that the electric field distribution characteristics of the three-phase transient are more obvious in the section closer to the electrode disc, and the electric field distribution is the most uniform in the section that is 1.4 m away from the furnace water. In the case of poor power quality, such as different bus voltage and three-phase voltage imbalance, the points of the maximum electric field intensity of the four surfaces change periodically with time, and the greater the bus voltage fluctuation, the more severe the impact on the transient electric field. The three-phase voltage imbalance will shift the peak value of the electric field intensity. The decrease or offset of electric field intensity in the electrode boiler caused by poor power quality will directly affect its heating efficiency. The electric field simulation results have a specific reference value for improving the internal electric field distribution and on-site operation and maintenance of the electrode boiler.

Optimizing intracranial electric field distribution through temperature-driven scalp conductivity adjustments in transcranial electrical stimulation

Transcranial electrical stimulation (TES) is a promising non-invasive neuromodulation technique. How to increase the current intensity entering the skull and reduce scalp shunting has become a key factor significantly influencing regulatory efficacy. In this study, we introduce a novel approach for optimizing TES by adjusting local scalp temperature to modulate scalp conductivity. We have developed simulation models for TES-induced electric fields and for temperature-induced alterations in scalp conductivity. Two common types of stimulation montage (M1-SO and 4 × 1 montage) were adopted for the evaluation of effectiveness. We observed that the modulation of scalp temperature has a significant impact on the distribution of the electric field within the brain during TES. As local scalp temperature decreases, there is an increase in the maximum electric field intensity within the target area, with the maximum change reaching 18.3%, when compared to the electric field distribution observed under normal scalp temperature conditions. Our study provide insights into the practical implementation challenges and future directions for this innovative methodology.

Electronic excitation of high-order spoof surface plasmons on metallic grating at terahertz frequencies

High-order spoof surface plasmon (SSP) mode on corrugated metallic surfaces can find many interesting applications, such as in imaging, sensing, transmission and enhanced radiation source, etc. In this paper, an efficient excitation method of the high-order SSP mode by using an injected electron beam on the uniform rectangular metallic grating is proposed and investigated numerically. Based on the matched wave momentum between the SSP mode and the electron beam, both the fundamental and high-order SSP modes can be excited on the structure by using a single injected electron beam. Numerical simulation results indicate that the maximum electric field intensity of the generated high-order SSP mode is about two orders higher than that of the fundamental SSP mode. In addition, the peak power of the excited high-order SSP mode is almost two times that of the fundamental SSP mode power by the same energy electron beam, which demonstrates the obvious advantage of the high-order SSP electronic excitation approach compared to the previous fundamental SSP mode excitation on the structure. The central working frequency of high-order SSP power spectrum is about three times that of the fundamental SSP power spectrum. Moreover, the influences of the injected electron beam energy on the excited SSP power spectrum are analyzed specifically. It is shown that the generated SSP power spectrum demonstrates a blue shift with the decreased working voltage of the electron beam simultaneously, with its peak power increasing. However, the working bandwidth is narrowed with decreased beam voltage, which further reveals its working mechanism of presented electronic excitation of the SSP mode. The presented studies provide a new method to excite a high-order SSP mode on the metallic grating, which can find some potential applications in high-sensitivity sensing, deep sub-wavelength waveguide, and many others in terahertz spectra.

Nanoarray of Vivaldi Rectenna for Infrared-energy Harvesting

This article presents the design of an array of rectennas operating at 28.3 THz for infrared (IR) energy harvesting applications. The basic element of the array consists of a Vivaldi-dipole rectenna composed of two arms made with different conductors (gold and titanium). A metal-insulator-metal (MIM) tunnel diode is used to rectify the THz ac current. The proposed MIM diode consists of a very thin layer of Al2O3 sandwiched between the two metal electrodes. Arrays of two, three, and four rectennas are investigated. The improvement of the energy captured by coupling several elements in the same structure with a common gap is also investigated. This array architecture, without feeding network, may reduce the number of rectifying diodes and, therefore, decrease losses and increase the overall efficiency. Finally, it has been found that the four-elements rectenna array has a maximum electric field intensity of 62.4 × 104 V/m at 28.3 THz.

Electric Field Analysis of HDPE/NR Biocomposite Due to Moisture Content Condition

It is critical to develop new insulating materials that can improve the performance of next-generation high-voltage cables used in the construction of future electrical networks. The high electric field reduces solid insulation resistance and causes partial discharge through imperfections in a dielectric, causing the dielectric to age and eventually fail. Moisture is one of the most serious factors the effect the high voltage insulation status of High-Density Polyethylene (HDPE) composites. The main goal of this project is to investigate the electric field intensity of HDPE due to moisture content condition when mixed with 10g, 20g, and 30g of various bio-fillers such as coconut coir fibre, pineapple leaves fibre, and oil palm empty fruit bunch. This can be accomplished by using the Finite Element Method Magnetics (FEMM) 4.2 software to create a two-dimensional (2D) axisymmetric electrostatic model. When compared to unfilled HDPE, the inclusion of bio-filler in HDPE increased the maximum electric field intensity due to moisture content condition. The intensity of the electric field varied with the different percentages of biocomposite loading and their permittivity due to moisture content condition. The results showed, due to moisture content condition, the maximum electric field intensity was significantly lower when HDPE was added with a 10% loading of the oil palm empty fruit bunch (EFB). As a result, EFB bio-filler was the best composition because it tends to improve dielectric properties by having a lower maximum electric field intensity which is 4.214Mv/m due to moisture content condition at the top sphere electrode when compared to other compositions.

Review of scientific instruments: Evaluation of adulteration in honey using a microwave planar resonator sensor.

A microwave microstrip line resonator sensor is developed as an alternative tool for detecting adulteration in honey. A honey-filled tube is placed at the position with the maximum electric field intensity. When the honey is adulterated, its permittivity is changed, leading to a distinct resonance frequency shift and enabling detection. Compared with the existing microwave sensors, this sensor offers the advantages of low cost, compact size, and easy fabrication. Moreover, quantitative analysis of the adulteration could be achieved. Electromagnetic simulation is performed using a co-simulation with CST and MATLAB. The simulation results reveal that the resonance frequency of the resonator decreases as the added water content increases, following a quadratic polynomial relationship. In the experiments, the results demonstrate a successive decrease in the resonance frequency from the empty tube, honey-filled tube to water-filled tube cases. Furthermore, honey samples with varying water contents (up to 70%) are tested, and the resonance frequency decreases with increasing added water content, which agrees well with the simulation results. In addition, there is a quadratic relationship between the two parameters. Principal component analysis is conducted on the transmission coefficients, and the first principal component decreases with increasing water content. With the addition of the second principal component, the cases of different water contents in honey can be well classified.

Investigation of Blade Receptor Number on the Lightning Attachment Behavior of Wind Turbine

The blade receptor plays an essential role in the lightning protection effect of wind turbines (WTs). In this investigation, five categories of WT lightning protection systems, with various pairs (two, three, four, six, and eight) of receptors on the blades, are evaluated by reduced-scale laboratory discharge experiments as well as by full-scale electric field calculations, from which the lightning attachment distribution and the electric field intensity of the WTs are obtained. Experimental results indicate that the lightning attachment probability of the blade insulation part decreases as the number of receptors increases, and that when the receptor number reaches four or more, an approximately complete protection for the WT blade can be achieved. Results also show that, for the WT model with two–six pairs of receptors on each blade, the lightning interception efficiency shows a trend of ascending with the increase of the receptor number, whereas an opposite trend is shown for the ones with six–eight pairs of receptors. Additionally, obtained simulation results show that as the number of receptors increases, the maximum electric field intensity shows a general decreasing trend. Finally, a theoretical analysis is carried out to explain the underlying mechanism of the observed phenomenon here.

Dynamic Behavior and Residence Characteristics of Space Charge in Oil-Paper Insulation Under Polarity–Reversal Electric Field

As one of the core components of the direct current (dc) transmission system, the converter transformer bears not only the alternate current (ac) electric field but also complex electric fields, such as polarity reversal. In the process of polarity reversal, the phenomenon of space charge residence occurs in the oil-paper insulation inside the converter transformer, which distorts the internal electric field, leading to insulation deterioration or even failure. However, studies on the dynamic characteristics of space charge during the reversal process and the mechanism of insulation degradation are not comprehensive. Therefore, in this study, a test pulse matching circuit was developed to accurately match the test pulse with the polarization voltage of polarity reversal and perform the multi-point rapid test of the space charge transient characteristics during polarity reversal. The space charge tests (of the unaged specimen) were performed at the polarity–reversal time of 60, 30, and 10 s, and the influence of polarity–reversal time on the charge residence characteristics of oil-paper insulation was compared and analyzed. Additionally, space charge tests were performed on oil-paper insulation samples with accelerated electro–thermal–mechanical aging treatment for 0, 2.5, 5, 10, and 15 days to compare and analyze the influence of oil-paper insulation aging degree on charge residence characteristics under the action of multi-physical field coupling. Research results indicate that the shorter the reversal time, the shorter the time required for the charge to dissipate, and the more the charge resides, the stronger its enhancement effect on the electric field. As the aging degree of the sample increases, the dissipation rate of the resident charge becomes slower during the reversal process, and the resident charge increases, so that the maximum electric field intensity inside the sample increases under the same polarization electric field. The study of the charge residence characteristics and the dynamic charge behavior during the polarity inversion process has important guiding significance for clarifying the deterioration mechanism of the converter transformer oil-paper insulation under polarity–reversal electric field.

Study on key factors and influence law of structural design of high-voltage electro-pulse bit

The High-voltage electro-pulse (HVEP) rock-breaking technique is considered a promising technique for deep well drilling due to its low energy consumption and relatively low drilling cost. The proper design of HVEP drill bits is indispensable for implementing Electro-pulse Drilling (EPB) and achieving rock breakdown through electric discharge. This paper designs and manufactures three kinds of electrode bits in diameter of 60 mm with different electrode structure arrangements, including coaxial cylindrical bits, multi-electrode pair bits, and electrode crossing bits, to investigate the influence of key parameters in electrode arrangement and structural design on HVEP rock-breaking. Finite element models are established for each of the three different bits to simulate and analyze the influence of factors such as drill bit structural design, circumferential spacing, grounding width, cone angle of the low-voltage electrode, and the electric field distribution inside rocks during the HVEP rock-breaking process. Simulation results show that the coaxial cylindrical drill bit exhibits the highest maximum electric field intensity among these three kinds of electrode bits, indicating its superior electric breakdown ability. An HVEP rock-breaking testing system is established, and real-time parameters, such as discharge current, are recorded during the drilling processes. An HVEP discharge process prediction model is also established based on time-varying resistance, and an improved integral electrode bit is tested experimentally. The experimental results show a significant improvement in terms of maximum drilling depth and removed rock volume. HVEP rock-breaking tests are conducted on different electrode bits, confirming the superior performance of the coaxial cylindrical drill bit. Tests are also conducted on different coaxial cylindrical drill-bit diameters in red sandstone, indicating that the drilling energy consumption decreases, and the energy utilization rate increases with an increase in drill bit diameter. This paper can guide the design of HVEP drill bits and explores the key factors that influence HVEP rock-breaking, which is significant for improving the efficiency of rock-breaking and reducing energy consumption.

Electric Field Characteristics of HDPE-NR Biocomposite Under Breakdown Condition

It is critical to develop new insulating materials that can improve the performance of next generation high voltage cables for creating future electrical networks. The high electric field reduces the resistance of solid insulation and produces partial discharge through imperfections in a dielectric, causing the dielectric to age and eventually fail. Thus, this project seeks to analyse the electric field intensity of High Density Polyethylene (HDPE) in breakdown condition when added with 10g, 20g and 30g of different types of bio-filler such as coconut coir fibre, pineapple leaves fibre, and oil palm empty fruit bunch. This can be achieved by creating a two-dimensional (2D) axisymmetric electrostatic model by using the Finite Element Method Magnetics (FEMM) 4.2 software. The results showed that the unfilled HDPE biocomposites have a higher electric field intensity than 10g, 20g, and 30g biocomposite. This indicates that the maximum electric field intensity changes according to the permittivity and voltage of the bio-filler under breakdown conditions. As a result, the maximum electric field intensity was much lower for HDPE added with a 20g of the pineapple leaves fibre. Hence, pineapple leaves fibre was the best composition as it tends to improve the dielectricproperties since it has a lower electric field intensity at the top electrode as compared to other compositions.

Optimization of Electric Stress in a Vacuum Interrupter Using Charnes’ Big M Algorithm

This article presents the optimization of electric stress distribution over the live electrode of an axisymmetric vacuum interrupter which is employed for 11 kV switching operations. The optimization is carried out by a classical approach using Charnes’ Big M algorithm used for solving constrained linear programming problems (LPPs). For this purpose, the objective function is obtained by applying multiple linear regression analysis by which a mathematical relationship between the maximum resultant electric field intensity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}^{\text {max}}$ </tex-math></inline-formula> ) over the surface of the live electrode and the critical dimensions affecting this stress. For this purpose, a set of 173 data is used which is prepared by varying the critical dimensions within the constraints of the overall dimension of the system and calculating the value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}^{\text {max}}$ </tex-math></inline-formula> over the surface of the live electrode by employing the boundary element method (BEM).

Electric field distribution around asymmetric agglomerate model reconstructed from FIB–SEM images of epoxy nanocomposite

AbstractThis study focussed on determining the electric field distribution formed by asymmetric agglomerates in order to elucidate the mechanism by which large agglomerates reduce the dielectric breakdown strength of nanocomposites. Epoxy nanocomposite sample was prepared by adding 2.5 vol% of TiO2nanoparticles with a primary particle size ranging from 30 to 50 nm. The three‐dimensional (3D) structure of the epoxy nanocomposites with a thickness of 5 μm was analysed via focussed ion beam and scanning electron microscopy. The 3D reconstruction was performed using 250 observation images, and a 3D model of the particle in the observational range was obtained. The electric field distribution for the 3D model of the agglomerate with the largest size was determined using the finite element method. In addition, we constructed a calculation model that effectively accommodate changes in the direction of the applied electric field. Subsequently, we examined the changes in the maximum electric field intensity around the agglomerate.

Design and optimization of a blue fluorescent microcavity-organic light-emitting diode (MOLED) on AZO anode for an algae excitation light source application

In this work, we present simultaneous organic light-emitting diode (OLED) stack optimization and optical modelling for a blue microcavity-OLED (MOLED) based on AZO anode to be used as algae excitation light in optical biosensor. Fluorescent materials (MADN and DPAVBi) were chosen as host:guest for the doped emissive layer due their known stability compared to phosphorescent and thermally activated delayed fluorescence (TADF) materials. The MOLED modelling was performed by targeting 470 nm as the maximal excitation wavelength and suppressing the emission in the algae fluorescence bandwidth (600–800 nm) in order to fulfil the sensor requirements. By using a bilayer hole transport layer/electron blocking layer (HTL/EBL) instead of a single HTL, the total thickness was adjusted to meet the resonance wavelength condition without loss of efficiency, while at the same time preserving a maximum electric field intensity in the emissive layer (antinode position). MOLED devices were fabricated by organic semiconductor evaporation on three dielectric distributed Bragg reflectors (DBRs) with 3 different numbers of TiO2/SiO2 (high-index/low-index) pairs and aluminum-doped zinc oxide (AZO) transparent electrode. Devices with 1.5 pairs as DBR showed not only an improved external quantum efficiency (+33%) compared to a standard OLED but also an increase of about 3 times the intensity of the peak at 470 nm combined to a lower emission in the 600–800 nm bandwidth, as aimed. This increase in the peak intensity should lead to a longer device lifetime, as the current density necessary to excite algae at 470 nm is significantly lower owing to the microcavity effect.

Analysis and design of overmoded coaxial Ku-band Cerenkov high power microwave oscillator with high efficiency

An overmoded coaxial Ku-band Cerenkov high power microwave oscillator with high efficiency is proposed. The distance between the inner and outer conductors of the slow wave structure (SWS) in the Cerenkov oscillator is smaller than the space wavelength of output microwave. The overmoded structure can increase the power capacity of the oscillator by increasing the transversal size of the device. The higher-order modes are introduced into the beam-wave interaction region intentionally, so that the intense relativistic electron beams (IREB) interacts with the fundamental and higher-order modes. Dual-mode operation leads impure mode component to output microwave, so the simple trapezoid inner conductor is designed to achieve mode purification and output pure TEM mode. The extractor is added at the end of the SWS, which enhances the axial electric field near the location and increases the modulation depth of the electron beam current passing through the region. The particle-in-cell (PIC) simulation results show that under the input power of 3.5 GW, the output microwave power is 1.8 GW, and the corresponding working efficiency is 51.4%, which is much higher than that of similar periodic devices. The mode of output microwave is pure TEM mode, and the maximum surface electric field intensity is 0.96 MV cm−1, which means that the probability of radio-frequency breakdown is low.

Research on corona characteristics and type selection of fittings in extra high voltage alternating current substation

In order to eliminate the energy loss and electromagnetic interference caused by corona discharge, the size selection and design of fittings under different voltage levels and different altitudes are studied in this paper. The corona discharge phenomena of several extra high voltage (EHV) alternating current (AC) substations are observed by ultraviolet (UV) imager. It is found that the areas with serious corona discharge in EHV AC substations are mainly concentrated on the shielding ring of terminal insulator string and shielding ball of conductor. The electric field calculation model is established for two typical fittings with serious corona discharge in COMSOL multiphysics software, and the distribution of electric field intensity on the surface of different sizes of fittings under the voltage level of 500 kV and 750 kV is calculated based on the finite element method. The results show that the maximum electric field intensity (MEFI) on the surface of the shielding ring of the terminal insulator string appears at the connection between the arc and the straight line of the shielding ring; the MEFI on the surface of the shielding ball appears in the ball head. Compare the numerical values of the corona onset field intensity (COFI) of the fittings at different sizes and altitudes calculated by using the physical calculation model of the COFI, so as to determine the size selection of the fittings at different altitudes and different voltage levels. The corona onset tests of fittings carried out in low altitude areas and high altitude areas verify the applicability of the size selection design of fittings at different altitudes and different voltage levels. The results show that the size selection design of fittings for 500 kV high altitude substation shall refer to the size selection of fittings for 750 kV plain substation.

Non-invasive stimulation with temporal interference: optimization of the electric field deep in the brain with the use of a genetic algorithm

Objective. Since the introduction of transcranial temporal interference stimulation, there has been an ever-growing interest in this novel method, as it theoretically allows non-invasive stimulation of deep brain target regions. To date, attempts have been made to optimize the electrode montages and injected current to achieve personalized area targeting using two electrode pairs. Most of these methods use exhaustive search to find the best match, but faster and, at the same time, reliable solutions are required. In this study, the electrode combinations as well as the injected current for a two-electrode pair stimulation were optimized using a genetic algorithm, considering the right hippocampus as the region of interest (ROI). Approach. Simulations were performed on head models from the Population Head Model repository. First, each model was fitted with an electrode array based on the 10–10 international EEG electrode placement system. Following electrode placement, the models were meshed and solved for all single-pair electrode combinations, using an electrode on the left mastoid as a reference (ground). At the optimization stage, different electrode pairs and injection currents were tested using a genetic algorithm to obtain the optimal combination for each model, by setting three different maximum electric field thresholds (0.2, 0.5, and 0.8 V m−1) in the ROI. The combinations below the set threshold were given a high penalty. Main results. Greater focality was achieved with our optimization, specifically in the ROI, with a significant decrease in the surrounding electric field intensity. In the non-optimized case, the mean brain volumes stimulated above 0.2 V m−1 were 99.9% in the ROI, and 76.4% in the rest of the gray matter. In contrast, the stimulated mean volumes were 91.4% and 29.6%, respectively, for the best optimization case with a threshold of 0.8 V m−1. Additionally, the maximum electric field intensity inside the ROI was consistently higher than that outside of the ROI for all optimized cases. Objective. Given that the accomplishment of a globally optimal solution requires a brute-force approach, the use of a genetic algorithm can significantly decrease the optimization time, while achieving personalized deep brain stimulation. The results of this work can be used to facilitate further studies that are more clinically oriented; thus, enabling faster and at the same time accurate treatment planning for the stimulation sessions.

Reduction of Deep Dielectric Charging of Polyimide by Incorporation of Glass Microsphere or Glass Fiber Reinforcement

In outer space’s extreme electron radiation environment, the insulating medium will experience a deep dielectric charging effect. As an excellent insulating medium, polyimide is widely used in spacecraft. In practical use, glass microspheres and glass fibers are often added to increase its mechanical strength. However, the influence of glass microspheres and glass fibers on deep dielectric charging effects has often been ignored in previous studies. Therefore, the work in this article established a 3-D deep dielectric charging model of glass microsphere and glass fiber reinforced polyimide. Using the model, the effects of glass microsphere and glass fiber volume fraction, glass microsphere spacing, glass fiber orientation, and 3-D glass fiber structure were investigated. The results show that the larger the volume fraction of glass fiber or glass microsphere, the more obvious the decrease of polyimide composite media’s average electric field strength. Under the same volume fraction, glass fibers are more favorable to reduce the average electric field strength than glass microspheres. The surface of glass microspheres will form charge accumulation, increasing local maximum electric field intensity, which is greater than the maximum electric field value of pure polyimide under electron radiation. When the spacing of glass microspheres decreases, the degree of electric field distortion increases, but the electric field value decreases when the microspheres contact each other. When the glass fiber orientation is perpendicular to the ground plane, it can better provide the electronic release channel, thereby reducing the deep dielectric charging effect. Using 3-D glass fiber structures can reduce the polyimide’s average electric field value and reduce the maximum local electric field distortion.