To improve the accuracy of travel calculations during the penetration of objects by high-speed carriers, this paper proposes a method for processing acceleration data during the penetration process. Through simulation, penetration acceleration data were obtained, and Fourier Transform was employed to analyze the time-frequency characteristics of these data. Given that penetration acceleration signals are often contaminated by high-frequency oscillatory noise, a novel signal processing approach is introduced. Using a controlled variable method in simulation, the frequency boundary between high-frequency noise and useful signals was identified. After applying a low-pass filter with a cutoff frequency of 10 kHz, the simulation results indicated that the processed signal provides sufficiently accurate travel information. On the hardware side, a specialized signal conditioning circuit was designed for the acceleration sensor signals, and its effectiveness was verified through Machette hammer experiments. Additionally, semi-physical simulation tests further confirmed the accuracy of the proposed travel calculation method. The results demonstrate that the improved method presented in this paper can significantly enhance the precision of travel calculations during the penetration of objects by high-speed carriers.

In piezoelectric transducer (PZT) energy harvesting, the synchronized electric charge extraction (SECE) technique is recognized for its desirable load-independent performance, while a self-powered SECE system remains a significant area of research. The electronic breaker is favored for its simplicity and reliability for achieving self-powering. However, current electronic breakers used in SECE tend to have a switch conduction time longer than one-fourth of the oscillation period (T-LC), which results in charge backflow and compromises its load-independence feature. In this article, a complete charge extraction electronic breaker (CEB) is introduced. The CEB controls the switch-off action of the transistor via an envelope detector, ensuring the complete extraction of the accumulated charge from the PZT. Building upon the proposed CEB, a self-powered synchronous inversion and charge extraction (SP-SICE) circuit is proposed. Simulations and experimental results validate the effectiveness of both the CEB and the SP-SICE circuit. The measurements show that the SP-SICE circuit achieves a peak power output of 333.9 mu W and a significantly enhanced load-independence range up to 1000 k Omega, which surpasses other existing techniques. The circuit has a stable output power without the need of a complex maximum power point tracking module, which makes it unprecedented among all relevant papers.

More and more important military facilities and command centers have been moved underground or protected with bunkers, so penetration munitions for such targets have become one of the important research directions for military equipment research institutes in various countries. The penetration fuze is a key part to achieve efficient destruction of penetration munitions, but the current high g accelerometers which are widely used in the penetration fuze have problems, such as the output signal mixing with the structural response of the projectile and noise signals, signal sticking and so on. In order to solve these problems, we designed a kind of capacitance sensor for penetration fuze. This paper further designed a signal processing circuit for the sensor, and the simulation and hammering tests were conducted to verify that the capacitive sensor for the penetration fuze can effectively suppress the structural response of the projectile and noise interference, and the signal sticking phenomenon can be reduced under the working condition of the penetration multi-layer target plate.

To improve the real-time performance and the target adaptability of penetration fuze detonation control systems, and to enhance the system fusion processing capability for multi-sensor information, this paper uses a modular design concept to construct a miniaturized (& oslash;38mmx4mm) fuze detonation control system that is capable of real-time processing of data from multiple information sources. The core component of this system is the GD32E230 microcontroller, which features a high dominant frequency and low power consumption. This device is integrated with a ferroelectric memory and signal processing circuits that match the sensors. To address the issue of unclear traditional acceleration signal penetration and the difficulties associated with the identification of these signals, the approach in this paper improves feature recognition accuracy through rapid acquisition and fusion of multiple types of sensor output signal, and self-adaptive identification of multilayered targets and single-layer thick targets is achieved. During the programming of the embedded system, the hardware register is operated directly, the instruction execution sequence is optimized, and the program execution efficiency is improved by using the function characteristic that some microcontroller unit peripherals do not occupy the central processing unit when working, thus allowing the intended purpose of improving the system's real-time performance to be achieved. A semi-physical simulation method is then used to verify the performance of the penetration fuze detonation control system. The results obtained show that the system has 100%-layer counting accuracy for multilayered targets and a relative error of less than 1% for the calculated residual velocities of single-layer thick targets, thus validating the effectiveness of the system.

Hypervelocity penetrators play a crucial role in breaching fortified structures designed to safeguard high-value targets. However, the signals captured by conventional accelerometers during the hypervelocity penetration of projectiles are often compromised by signal aliasing, which poses challenges in extracting features from the penetration signals. This article proposes a high-g magnetoelectric velocity sensor with antialiasing capabilities. The sensor is sensitive to velocity loss produced when the projectile penetrates the target, rather than deceleration. The design concept and theoretical feasibility of the magnetoelectric sensor are detailed. Based on the sensor's joint simulation model, the relationship between the attenuation of the sensor's response to the oscillation signal and the signal frequency is analyzed. To quantitatively assess the magnetoelectric sensor's antialiasing performance, the single-layer simulation overload and the penetration overload of a projectile penetrating a six-layer target plate are inputted to calculate the adhesion coefficients of sensor signals. The results indicate that the sensor effectively attenuates the high-frequency oscillation signal, thereby reducing the degree of adhesion of the feature signal. Compared with the adhesion coefficients of the acceleration signal, the magnetoelectric output signal shows reductions of more than 80% in both its average layer coefficient and average interlayer coefficient before filtering, followed by corresponding attenuations exceeding 60% after filtering. These results demonstrate the antialiasing performance of the proposed sensor. It is able to extract penetration features that cannot be distinguished by traditional accelerometers.

The average output power of piezoelectric generator is small, which can not directly drive the load to work. In order to meet the energy supply demand of electromechanical system, it is necessary to design a matching energy harvesting circuit. Although the typical energy harvesting circuit is simple in structure and easy to build, the collection efficiency is low. Therefore, a new parallel synchronous switching circuit is proposed in this paper to improve the output power of piezoelectric generator. Through analyzing the circuit and optimizing the components used, a passive switching circuit is designed by using the on-effect of transistors, which overcomes the defect of external switching signal control circuit. Through experiment, the output power of the improved parallel synchronous switch circuit is 2.23 times that of the classical energy harvesting circuit.

When the traditional high-g acceleration sensor penetrates the hard multi-layered target, it is easy to cause the overlap of the penetration overload. The rigid body signal is submerged in the vibration signal, resulting in the error of the layer-counting recognition algorithm, and it is difficult to judge the time of the penetration ammunition. Based on the principle of the capacitance sensor and the piezoelectric sensor, a composite sensor for penetration fuze is designed in this paper. On this basis, a layer-recognition algorithm based on capacitance and piezoelectric signal fusion is designed, and its feasibility is verified by software simulation.

With the development of the times, the concept of modern warfare is constantly changing and precision strikes have become an important mode and means of combat on the modern battlefield. It is of great strategic value to research and realise hard target penetration munitions that can strike accurately and effectively destroy high-value targets. The key to the efficient destruction of hard targets by penetration munitions is the penetration fuze, the core of which is the initiation control strategy in high overload conditions. By investigating the current state of research on intrusion fuze initiation strategies, the future trends of layer counting identification and cavity counting identification are envisaged.

Mastering mechanical properties of polymers at nanometer scale is highly demanded yet remains challenging. Pioneering advances determined Young's modulus in ultrathin polymer films and attained unprecedented results including rubbery stiffening. However, many viscoelastic properties such as dynamic mechanical behavior of freestanding nanoconfined polymer films are still unknown. Here we demonstrate striking changes of stiffness and the ratio between elastic and viscous responses in thin PDMS films, using a microvibrational system which enables direct measurements of dynamic stress-strain relation of freestanding films. The results show that elastic modulus is enhanced by a factor of 135 in 50 nm films than the bulk, while the viscous response substantially increases at strains >0.05 in 125 nm films. These observations exhibit significant alterations of viscoelasticity under nanoconfinement. With insights on the underlying mechanism of these results, this study is expected to provide new evidence toward gaining a comprehensive understanding of nanoconfinement effect of soft matter.

Explosion point control must be achieved for a projectile striking a multi-layer hard target via layer detonation. However, multiple oscillating signals are superimposed on the penetration overload signal of the projectile's sensor when a high-speed warhead penetrates through multiple layers of a hard target. Signal adhesion occurs in the sensor when an acceleration sensor is used to acquire the penetration overload signal, causing the projectile to be unable to identify layer penetration characteristics and thus seriously affecting the layer detonation accuracy. A special layer metering sensor is designed in this paper to resolve the over-sensitive sensing problem caused by rigid-body overload during the projectile penetration process for multi-layer hard targets. When the vibration frequency of the measured system is far higher than the natural frequency of the sensor, the relative vibration displacement amplitude of the sensing mass block inside the sensor is related linearly to the displacement amplitude of the measured system. Based on this principle, this work investigates the mechanisms and the structural design of the layer metering sensor and optimizes the main sensor parameters that affect its output characteristics. The sensor output characteristics were tested using a multi-impact simulated test device developed by the authors. The test results show that the layer metering sensor's output signal has a single waveform with easily identifiable characteristics that can effectively avoid the influence of projectile body vibrations on the sensor output signal, which means that layer detonation can be controlled accurately for high-speed penetration through multi-layer hard targets.

Aiming at the protection of the internal components of the projectile during penetration, the cushion performance of common protective materials such as polyurethane, felt, polytetrafluoroethylene (PTFE), and copper were tested. The test results show that the copper and felt have a certain cushioning effect, which can reduce the acceleration amplitude of 23,000 g by 18% and extend the pulse width of acceleration overload. The cushioning effect of PTFE material is not obvious, but it can play a role in mechanical filtering, making the acceleration curve smoother. Polyurethane material will increase the acceleration amplitude of the buffered part, it is not suitable as a buffer material.

During the working process of the fuze insurance institution, the metal coil spring as a resistance element may cause failure due to fatigue fracture and stress creep relaxation, thereby affecting the reliability and stability of the fuze safety system. To solve this problem, a kind of variable stiffness spring with negative stiffness characteristic is proposed in this paper, which is composed of two magnets. This spring has the advantages of simple structure and rich stiffness characteristics. It is used in fuze recoil insurance institutions to meet the requirements of fuze security system service handling security and reliable release of insurance at launch, providing new features for improving the performance of fuze insurance institutions Technical approach.

随着低功耗微机电系统的发展,越来越多的微型发电机涌现,其中压电发电机为典型的代表.针对一种基于风致振动机理的柔性压电发电机进行了实验及仿真研究:建立柔性悬臂梁流固耦合仿真模型,分析柔性梁在流场中的力学环境及颤振机理;探究压电悬臂梁在亚颤振临界风速及超颤振临界风速条件下电压输出特性及其给电容充电的性能.结果表明,当风速低于颤振临界速度时,单个压电悬臂梁输出电能较小,接近于零.当风速高于颤振临界速度时,输出电压为类正弦曲线,峰值可达20V.在超颤振临界速度条件下,单个压电悬臂梁为10μF电容充电10s可达22V.微型压电发电机为低功耗微机电系统设备供电成为可能.

With the development of micro-machining technology, the application of micro-channel is becoming more and more popular. In this paper, we design a set of time-delay device based on micro-channel and micro-fluidics technology. This paper describes the time-delay device's working principle and analyses the micro-channel's flow characteristics by simulation method based on Coventerware. From studies on the micro-channel's cross section, geometry and dimension parameters, the micro-channel's optimal form and dimension can be obtained. Finally, this paper chooses ultra-machining process to fabricate the time-delay device.

Piezoelectric energy harvesters have been studied extensively because they show considerable promise for use in both military and commercial applications. In order to improve the output capability of the piezoelectric energy harvester, the perforated piezoelectric cantilevers were designed in this work. To study how the hole on the cantilever affected the output characteristics, this paper analysed the position and size of the hole separately. The results show that, perforating the cantilever can cause stress concentration of the piezoelectric cantilever, and improve the output capacity.

Piezoelectric energy harvesters have been studied extensively because they show considerable promise for use in both military and commercial applications. In this work, research was conducted into the core component of a piezoelectric energy harvester, i.e., the piezoelectric cantilever. The phenomenon where the piezoelectric cantilever has a very low output when no substrate layer is present can be explained using neutral plane theory. The relationship between the neutral planes position and the piezoelectric cantilever's output power can be studied in depth through analysis of this phenomenon. A mathematical model of a vibrating piezoelectric cantilever is established and the neutral plane position and open-circuit voltage of a vibrating piezoelectric cantilever are deduced based on Euler-Bernoulli beam theory. Calculations and finite element simulation results show that the neutral planes position in the piezoelectric cantilever is dependent on the elastic moduli and thicknesses of the piezoelectric and substrate layers and that the output of the piezoelectric cantilever is also closely related to the neutral plane's position. To study how the neutral plane's position affects the output power of the piezoelectric cantilever, polyvinylidene fluoride (PVDF) piezoelectric cantilevers with different substrate layers but the same piezoelectric layer were fabricated and the output powers of these layers were measured. Experimental results show that the composite piezoelectric cantilever's performance is enhanced in terms of its output voltage, average power and power density as the neutral plane is gradually moved further away from the mid-plane of the piezoelectric layer.

The wide application of electroformed nickel in fuze leads to a research hotpot on its material mechanical properties. The objective of this work is to analyze the mechanical properties of electroformed nickel through analyzing its micro-structure. In this paper, uniaxial tensile tests and EBSD tests were conducted on three sets of electroformed nickel with average grain sizes below 1 um, and the mechanical properties and microstructures are obtained. To further study the effect of microstructure on the mechanical properties of electroformed nickel, simulations based on crystal plasticity finite element model are conducted. From experiments and simulations, the yield strength was found to be dependent of micro-electroformed nickel's grain size and texture, and the elastic modulus was found to be dependent of micro-electroformed nickel's texture. Both the texture intensity and texture type influence the elastic modulus and yield strength of micro-electroformed nickel.

为提高微小型压电发电机的发电性能,设计了一种悬臂梁式的柔性风力发电机,通过实验与理论相结合的方法,分析了柔性悬臂梁振子的结构类型和结构尺寸对发电机输出电压的影响规律.研究发现,合理选择压电振子的长、宽以及基底厚度,使压电振子在给定风速下产生共振将有助于提高发电机的发电能力.在0～50 m/s的风速范围内,对不同结构尺寸的柔性压电发电机的发电能力进行了测试,实验结果表明:在压电振子能够发生共振的前提下,基底的厚度对发电性能的影响不大,而振子的长度及宽度对压电发电机的输出电压影响较大,且输出电压不随振子尺寸单调递增;在其他参数均为定值的前提下,压电振子的最优长度为40 mm,最优宽度为11.3 mm.

This paper proposes a novel structure for pre-rolled flexible piezoelectric cantilevers that use wind energy to power a submunition electrical device. Owing to the particular installation position and working environment, the submunition piezoelectric cantilever should be rolled when not working, but this pre-rolled state can alter the energy harvesting performance. Herein, a working principle and installation method for piezoelectric cantilevers used in submunitions are introduced. To study the influence of the pre-rolled state, pre-rolled piezoelectric cantilevers of different sizes were fabricated and their performances were studied using finite element analysis simulations and experiments. The simulation results show that the resonance frequency and stiffness of the pre-rolled structure is higher than that of a flat structure. Results show that, (1) for both the pre-rolled and flat cantilever, the peak voltage will increase with the wind speed. (2) The pre-rolled cantilever has a higher critical wind speed than the flat cantilever. (3) For identical wind speeds and cantilever sizes, the peak voltage of the flat cantilever (45 V) is less than that of the pre-rolled cantilever (56 V). (4) Using a full-bridge rectifier, the output of the pre-rolled cantilever can sufficiently supply a 10 μF capacitor, whose output voltage may be up to 23 V after 10 s. These results demonstrate that the pre-rolled piezoelectric cantilever and its installation position used in this work are more suitable for submunition, and its output sufficiently meets submunition requirements.