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Dynamic compressive behavior of 2 kinds of Al/Teflon reactive materials samples are analyzed by using the Split Hopkinson pressure bar. The mass percentage of the samples is 26.5% Al and 73.5% Tefl...

In order to simulate the damage effect of space high-energy particle interacting on ferroelectric random access memory (RAM), the theoretical model of laser supported detonation wave is derived. Also, the equivalent target model of the collision between the core region of the ferroelectric RAM and high-energy particles is established. The high-energy oxygen and nitrogen atoms are selected as the sources of high-energy particles in the air at normal temperature and pressure. The source of particles that bombard the ferroelectric RAM is used to simplify the simulation of the composite target. Meanwhile, the theory of molecular reaction dynamics, the particle collision software based on the Monte Carlo algorithm provided by Stopping and Range of Ions in Matter (SRIM), is used to simulate the collision of high-energy particles with air. The simulated results show that the electron stopping capability of air to high-energy nitrogen and oxygen atoms is far greater than the stopping capability of the nucleus; when the incident energy of high-energy particles is gradually increased, the blocking power of air to electrons increases first and then decreases. Also, the capability to stop the particles of the target nucleus is gradually reduced; under the condition of the implantation, the energy of nitrogen and oxygen atoms are both 1.8 MeV, the movement of the particles in the first seven layers of the target is relatively straight, and the phenomenon of deviation from the axis of symmetry is apparent in the silicon substrate. Due to the presence of more energy in the first seven layers of the target, it is not possible to see the more obvious lateral diffusion. The simulated results will provide a valuable reference for the prediction of single-event effects induced by ground-based pulsed laser simulating space high-energy particle irradiation.

Aluminum honeycomb framework reinforced Al/PTFE material is a kind of high inert energetic material, which has higher strength and structure advantages than that of pure Al/PTFE material. In order to meet the requirements of special penetration/blasting performance, this paper adds aluminum honeycomb framework with arm length of 1.5 mm into the traditional formula Al/PTFE (mass percentage of Al and PTFE is 26.5% and 73.5%). The energetic material reinforced by aluminum honeycomb framework (20.5% Al/73.5% PTFE/6% aluminum honeycomb) is obtained by cold pressing sintering，and the experimental evaluation of release energy generated by high velocity impact in vacuum was performed by using two-stage light gas gun loading system, transient optical fiber pyrometer measurement system, overpressure measurement system and infrared thermal imager measurement system. Experimental results show that the impact reaction temperature is about 700 °C in vacuum in the velocity range of 0.96–1.5 km/s, and the energy release of the specimen increases with the increase of impact velocity. When the impact velocity is greater than 1.5 km/s, the specimen fully reacts, and the energy released by the complete reaction of the specimen does not exceed 8.3 kJ/g.

Pb1·0[Zr0·49Ti0·46(Li0·25Sb0.75)0.05]O3(PZT-5H) is easy to break under overload. To explore the electrical output characteristics of fractured PZTs when they are subjected to repeated impact, experiments were performed by using SHPB loading and testing system. The results show that the irregularity of internal defects for PZT has different breaking strengths. The breaking strength of PZT-5H in experiments varies from 30 MPa to 50 MPa. The electric displacement and stress can meet the classical piezoelectric equation without considering the influence of fracture on discharge, but the dynamic and quasi-static piezoelectric constants d33 are quite different. With the increase of stress rising rate, d33 increases gradually. Under different impact velocities, the relationship between electric displacement and stress peak is nonlinear; Whether it is electrical short-circuit or open-circuit, the influence of fracture on the electrical output is limited. The influence of crack caused by overload on discharge can be ignored when the electrode material does not be damaged.

The structures composed by metal fiber and auxiliary elastomer are stretchable and have potential application under larger strain. Nowadays, interfacial failure is still the key problem affecting practicability of the structures. The result of typical pull-out test indicates that three stages exist in this pull-out process: elastic deformation, interfacial debonding and interfacial friction. For the sake of determination of interfacial parameters, a numerical method has been proposed to characterize the damage initiation point by using the slope of force-displacement curve of pull-out experiment. Furthermore, based on the basic material and interfacial parameters, extensive simulations have been conducted to study parametric effect on the general mechanical behavior of structures, including interfacial elastic modulus, failure strength and damage evolution law and friction. The results indicate both interfacial cohesive and friction contribute to the force increasing after damage initiation points.

To investigate the dynamic compressive behavior of zirconium filaments/aluminum/polytetrafluoroethylene (mass fraction of Zr fiber/Al/PTFE of 3%/23.5%/73.5%) active materials, traditional formula Al/PTFE active materials (Al/PTFE mass fraction of 26.5%/73.5%) and Al/Zr/PTFE active materials were prepared by cold pressing sintering process. The microscopic morphology and impact reaction behavior of the material by scanning electron microscopy (SEM) and high-speed camera are observed. The dynamic compressive experiments of the two materials are carried out by using separate Hopkinson bar (SHPB) test system. The results show that the Al/PTFE by adding active metal zirconium (Zr) filaments can improve the dynamic compressive properties of conventionally Al/PTFE. The failure strength of active material is increased from 32 MPa to 110 MPa comparing with conventionally Al/PTFE active materials, and the increase is about 243.75%. When the strain rate is 2500–4000 s−1, Al/Zr/PTFE specimens exhibit the same elastic–plastic mechanical behavior as conventionally Al/PTFE specimens. The behavior of the two specimens can also be divided into three stages: compressive deformation, crack generation and hot spot initiation (there are microscopic holes around Zr fibers, and the collapse and expansion of holes is the main reason for the formation of hot spots).

The fission reactions of 238U induced by D-T neutrons were investigated by neutron activation technique and low-background HPGe-γ spectrometer. The half-life was used to identify the possible daughter nuclide. The fission cross-sections of 238U(n,f)89Rb reaction induced at the neutron energy around 14 MeV, i.e., 14.1 ± 0.3, 14.5 ± 0.3 and 14.7 ± 0.3 MeV, were measured precisely. The neutron flux was monitored by accompanying α-particle of the T(d,n)4He reaction and the neutron energies were determined by the cross-section ratio of 90Zr(n,2n)89Zr to 93Nb(n,2n)92mNb reaction. The fission cross-sections of the 238U(n,f)89Rb reaction are 33.2 ± 2.1 mb, 32.2 ± 2.0 mb, and 32.6 ± 2.1 mb, corresponding to the above neutron energy points.

In view of the wide demands of sandwich structure with aluminum honeycomb material as core layer in many important fields such as automobile manufacturing, transportation, aerospace, protection engineering as well as ship, etc. In order to reveal the interacting duration and microscopic characteristics generated by high-velocity impact on Carbon Fiber Reinforced Plastics/Aluminum honeycomb core sandwich panel (CFRP/Al HC SP), a series of experiments about combined type and split type targets impacted by cylindrical steel projectiles at the velocity of nearly 300m/s have been performed by using one-stage light gas loading system and related velocity measurement systems established by ourselves. The residual velocities and the interacting duration are measured during the process of the projectile piercing through combined type target and each part of the split target, respectively. Meanwhile, the simulations have been conducted under the corresponding experimental conditions, and the microscopic characteristics of the CFRP specimens have also been analyzed by using scanning electron microscopy (SEM). The results shows that the total interacting duration on the whole combined type structure is 164.5 μs, and duration consumed in the front CFRP panel, Al HC and the rear CFRP panel in combined target are 32.5 μs, 91.7 μs and 40.3 μs, respectively. The damage morphology, residual velocity and interacting duration in each parts of the combined type target obtained by numerical simulation of ABAQUS/Explicit module are basically consistent with the experiments, and the crack, delamination, fracture and drawing wire of carbon fiber filaments have been given by cylindrical solid steel projectile impacting on CFRP panel at the given experimental conditions. Keywords: High-velocity impact, CFRP/Al HC SP structure, Interacting duration, ABAQUS/Explicit module, Microscopic characteristics

In order to improve the stability of PZT-based sensors, the mechanical, dielectric, ferroelectric and piezoelectric properties of PZT-5H under impact load were studied experimentally by using the separated Hopkinson pressure bar (SHPB) with an electrical output measurement device. At the same time, the experimental study on the material properties of PZT-5H before and after the impact was carried out. The effect of impact cracks on the output voltage of PZT-5H was also analyzed. The results show that the dynamic piezoelectric constants of PZT-5H under low stress impact (10–50 MPa) are different from those under quasi-static state, and the empirical relationship between them and the peak stress is obtained through experiments. The dielectric properties of PZT-5H did not change under low stress impact, but micro-cracks occurred in the material and dielectric loss increased at high frequencies. Under short circuit, the residual polarization intensity of PZT-5H decreases sharply due to impact load. While the impact load causes the secondary polarization and the increase of the residual polarization intensity of PZT under open circuit. When the stress is over 45 MPa, the PZT-5H breaks. The formation of cracks causes abnormal discharge voltage and gap discharge.

In view of the objective reality that it takes a long time for debris to locate the impact point when debris impacts the spacecraft bulkhead, timely and accurate determination of the location of the impact source is the premise and basis for damage repair, which is of great significance to the safety of astronauts. In this paper, the experiments of 2A12 aluminium plate impacted by 2A12 aluminium projectile under different impact parameters have been performed by using the self-built acoustic emission testing system and two-stage light gas gun loading system. The calculated coordinates are compared with the experimental coordinates by using triangular positioning method, quadrilateral positioning method and acoustic emission (AE) signal processing method based on Wavelet transform. The experimental results show that the positioning accuracy of quadrilateral positioning method is better than that of triangular positioning method, and the acoustic emission signal processing method based on wavelet transform is obviously better than that of quadrilateral positioning method.

In order to deeply reveal the microscopic damage mode and microscopic damage mechanism of Carbon Fiber Reinforced Plastic laminates (CFRP laminates) impacted vertically by the ice projectile at high velocity. In this paper, the loading system of the one-stage light gas gun, the liquid nitrogen circulating cooling system, the impact pressure measuring system and the high speed camera acquisition system are used, and the experiments of the spherical ice projectile (simulated hail ice, SHI) with diameter of 11 mm impacting CFRP laminates vertically at the velocity of 50-200 m/s were carried out. The impact pressure of the SHI impacting the target, the strain of X-Y in the two main directions at the impact point were measured, and the deflection/ time history curve at the impact point during the impact process was obtained. By using ABAQUS/Explicit finite element software, the numerical simulation of high-velocity vertical impact of SHI on CFRP laminates was compared with the image acquisition results of the high speed camera at different moments during the impact process, and the failure morphology and process of SHI was analyzed. At the same time, the delamination of the target obtained by numerical simulation is compared with the cracking of the CFRP fiber reinforcement and the delamination of the epoxy resin interface obtained by microscopic SEM observation, the correctness of using cohesion model to describe the micro-damage of CFRP laminates induced by SHI impacting vertically at high speed was verified. The damage failure threshold of CFRP laminates under the impact load of SHI under given experimental conditions was obtained. By establishing a three-point simply supported physical model, the ultimate deflection of laminated plates subjected to delamination failure was analyzed. Based on the measurement of strain and deflection at impact point, the valuable reference for the prediction of delamination failure in CFRP laminates can be provided, then the detection of the micro-damage to the surface composite part of the aircraft will be realized by the control of the sensor. Keywords: CFRP laminates, Cohesion model of ice projectiles, Microscopic damage model, Microscopic damage mechanism, Delamination failure prediction

In view of the wide demands of sandwich structure with porous material as core layer in many important fields such as protection engineering, aerospace, automobile manufacturing and ship, etc. In order to reveal the energy absorption and damage characteristics of high velocity impact aluminum foam core and CFRP/aluminum foam core structure, the quasi-static loading system, one-stage light gas gun loading system, the impact pressure testing system and the high-speed camera acquisition system were used to perform the quasi-static compression experiments of aluminum foam and the projectiles with different materials impacting on the aluminum foam core and CFRP/aluminum foam sandwich structure at the speeds of 100–300 m/s. The influences of impact velocity and projectile’ density on the damage characteristics of CFRP/aluminum foam sandwich structure and the attenuation effect of shock wave in sandwich structure have been studied. The experimental results showed that the curve of stress and strain has three typical zones similar to porous materials: elastic zone, yield platform zone and compaction zone under quasi-static compression loading. Due to its brittle and low tensile strength of aluminum foam material, the single aluminum foam plate has poor ballistic performance under the high-speed impact of projectiles with different materials. Therefore, closed cell aluminum foam needs to be combined with high strength panels to form sandwich structure to improve its ballistic performance. Keywords: High velocity impact, Aluminum foam core, CFRP/aluminum foam sandwich structure, Energy dissipation, Damage characteristics

With pancake-coil electromagnetic launcher as a research object, the experimental platform of the pancake-coil electromagnetic launch intercepting system with 50-kV pulse capacitors as energy storage was built and tested for discharge to study the electromagnetic launch intercepting system. The oscillation problem of the current flowing through freewheeling loop was solved by connecting the reverse-cut diode stack in series with trigger vacuum switch (TVS). However, due to limiting power component, the experimental system can work normally at 9.4-kV capacitor voltage. A proportional 3-D model of the pancake-coil electromagnetic launcher and an external excitation circuit model were established based on the structural and circuit parameters of the experimental system to perform simulation. The accuracy of the simulation model was proved by comparing the simulated and measured currents obtained under same capacitor parameters. Based on the established finite element model, maximum launching capacity and energy efficiency of the experimental system platform were estimated through simulation, and the space–time distribution characteristics of the magnetic field were analyzed during the launching process. In addition, the electromagnetic-structure coupling simulation was carried out to study the deformation problems of components of launcher by sequential coupling. All the work done in this paper provides guidance for a detail research, and we want to try to improve our electromagnetic launch experimental system.

Aiming at the reality of different potential differences on the surface of a spacecraft, it is very difficult to obtain a potential difference in the laboratory. In order to disclose the influence of potential difference on discharge, we have segmented a spacecraft surface into different parts with reserved gaps, in which gaps reserved in two adjacent surfaces are added resistances to create a multi-surface with different potential differences, and the low-potential surface as a, impact target in the split targets. In order to disclose the discharge characteristics, it is very vital to establish the charging and discharge systems. Therefore, a circuit system with different potential differences, discharge testing system, and ultra-high speed camera acquisition system are established by ourselves, and combining with a two-stage light gas gun loading system, nine sets of experiments have been conducted about hypervelocity impact on a 2A12 aluminum target with different potential differences. In experiments, gaps of a 2A12 aluminum target are the same among different potential parts in every experiments the gaps are 2 mm, 5 mm and 10 mm and applied voltages are 300 V, 200 V, and 100 V in every group experiment, respectively. The experiments have been performed at the impact velocity of about 3 km/s and the incidence angle of $$60^{\circ }$$ (between projectile flying trajectory and target plane). Voltage and current probes are adopted to acquire discharge voltage and current during the process of impact. The experimental results show that the discharge induced by impact plasma is produced among high- and low-potential targets, the gaps with 2 mm, 5 mm, and 10 mm can evoke a primary discharge among different split targets, and a primary discharge current peak and discharge duration increase with the increase of the applied voltage at the same gap of split targets. Meanwhile, a secondary discharge is induced at the conditions of the gap for 2 mm and corresponding applied voltage of 200 V as well as 5 mm and 300 V, respectively.

In order to determine the positions of debris collision spacecraft accurately, the experiments have been performed to impact orthogonal stacking two-dimensional Polyvinylidene fluoride (PVDF) piezoelectric film at different collision speeds based on the piezoelectric effects of the PVDF film by using two-stage light gas gun loading system and the self-constructed positioning system. The debris source was positioned accurately by PVDF strips sensor and testing system, which has been established to extract piezoelectric signals of the PVDF film during the process of impacting. The visualization of the position for debris impacting spacecraft was achieved through the LABview language programme and signal processing acquired by the signal acquisition system in the experiments. The experimental results show that the positions of the debris impacting source can be realized accurately by the piezoelectric effects of the orthogonal stacking two-dimensional PVDF film, the flight velocity and the incidence angle of the debris can be determined by installing the double-set PVDF film as the targets with a certain spacing.

Stacked piezoelectric ceramics (PZT-5H) are often used as sensors and pulsed power sources in moving objects. They will be subjected to a larger overload force when the moving objects collide with the target. In order to study the influence of the connection mode (parallel/series) of ceramic chips on the electrical output characteristics of stacked PZT-5H during overload, many experiments were performed using a nylon projectile to impact the stacked piezoelectric ceramic with different impact velocities by using a one-stage light gas gun as the loading device. The influence of a full bridge rectifier circuit on electrical output characteristics of the stacked PZT-5H was analyzed.

In the field of ammunition, piezoelectric ceramics are increasingly used as part of impact fuze systems. It is an urgent problem to improve the low-temperature storage and low-temperature environment adaptability of piezoelectric ceramic power supply. In order to study the dynamic mechanical and electrical response characteristics of PZT-5H at − 40 to 25 °C, the static electrical parameters of PZT-5H at different temperatures were measured, and the Hopkinson bar experiments at different temperatures and impact velocities were carried out by using the self-established low-temperature mechanical and electrical test system. The variation of resistivity and relative permittivity of PZT-5H from − 40 to 25 °C is obtained by experiment, and the relaxation time of PZT-5H is obtained according to Debye’s theory. Combined with the observation of scanning electron microscope (SEM), the influence mechanism of porosity and crack on the electrical output characteristics of piezoelectric ceramics was obtained. The mechanism of the freezing effect of piezoelectric ceramics at low temperatures is obtained through space charge theory analysis. The variation of the dynamic piezoelectric voltage constant with temperature and time in the elastic region measured by the experiment is clarified.

To evaluate the reactive energy release of the Al/Polytetrafluoroethylene (PTFE) mixed powder (Al and PTFE with a mass percentage of 26.5%/73.5%). Based on the traditional formula, three kinds of Al/PTFE test samples with different dosages (4, 6.5, and 9 g) were mixed. By using the self-designed airtight container, and combining with the overpressure sensor, the transient optical fiber pyrometer, and the infrared thermography. The overpressure , the visible light radiation temperature in the closed container, and the infrared light radiant temperature of the container’s outer wall have been obtained by real-time measurements during the process of cooking off, and the reaction products are analyzed by X-ray energy spectrum (EDS) and X- ray diffraction (XRD). The experimental results show that most of the solid products of Al/PTFE powder in the closed container are AlF3 and a small number of intermediate carbon compositions. The released energy during the firing process of the active material Al/PTFE increases with the increase of the mixing amount; The bake-off energy of active material Al/PTFE mixture per unit mass in a closed container is about 10.2 kJ/g, and when the oxygen content in the closed container is sufficient, active material Al/PTFE per unit mass releases more energy.

The infrared thermal imaging system was used in order to investigate the temperature field distributions for optical glass lenses irradiated by femtosecond pulsed laser. The experimental research of the temperature field distributions on the surface of the H-K9L optical glass lenses with anti-reflection film and film free have been accomplished by this system combining with the irradiation at different frequencies and actuation duration by the femtosecond pulsed laser. The angle between the normal direction of the mirror surface and the laser output was 45 degrees. Experimental results showed that the coating of the lens on surface increases the distortion of the heat-affected zone and the temperature field, the penetration time increases as well as the temperature gradient decreases at the same time, which was caused by the reflection reducing coating on the surface of the lenses and this kind of coating has a certain protective effect to the optical lenses. The output frequencies of the laser presented a positive correlation linearly to the maximum surface temperatures of the lens in a certain range when the output energy of single laser pulse was constant. The spectral of temperature field was dominated by low frequency signals, the higher the laser output frequency was, the larger the amplitude of the spectrum signals was. The evolutionary processes of temperature for feature points at the edge of heat-affected zone were basically the same, therefore the laser irradiation in a small angle less than 45 degrees had little influence on the distributions and the evolutionary processes of the surface temperature fields in the heat-affected zone for thin targets.

Solar array is one of the core components of spacecraft exposed to space environment; it is vulnerable to the impact from space debris. Discharge of solar array induced by ultrahigh-speed collision will produce a serious threat to the power supply system of spacecraft in orbit. In order to mitigate discharge effect and simulate working state of solar array effectively during debris impacting on solar array, realizing charging through sunlight irradiance on the ground simulating experiments is very difficult. Therefore, the inverse process of solar energy generation is adopted by applied power supply to solar array. In addition, loading and measurement systems of discharge have been established in a laboratory. A two-stage light gas gun was used to launch the projectile to impact on solar array at the applied power supply voltage of 100 V, and the spacings among the cells of solar array were 0.6, 3, and 5 mm, respectively. The applied power supply system, the diagnostic system of plasma characteristic parameters, and the measuring system of discharge current and voltage were constructed to provide voltage for solar array, diagnosing characteristic parameters of plasma and measuring discharge parameters, respectively. Six sets of experiments have been performed to measure discharge current and voltage induced by plasma during 2A12 aluminum projectile impacting on the solar array with carbon fiber reinforced plastics Al honeycomb sandwich and 2A12 aluminum substrates, respectively. The experimental results showed that the discharge did happen during 2A12 aluminum projectile impacting on solar array, and the discharge current among the cells increased with the increase of the impact velocity under the given experimental conditions. Also, increasing spacings among the cells of solar array could indeed mitigate or inhibit plasma discharge effects created by hypervelocity impact on solar array at the same projectile incident angles and applied power supply.

To introduce the application background the self-powered technology for Fuze bridge fire, high overload microthermal battery activation, rocket ignition, and the aircraft escape actual condition lifesaving system ignition power supply, which intends to use the high-speed impact of piezoelectric ceramic in the process of missile launching high overload pressure or missile and target intersection in the process of high overload stress wave of piezoelectric ceramics and the transformation of power, for closer to confession technology for Fuze bridge ignition, high overload microthermal battery activation, rocket ignition, and aircraft escape system engineering problems. The stress wave propagation in the PZT-5H piezoelectric ceramic composite target and load resistance effect to the electrical output characteristics is investigated under the strong shock loading; the experiments have been performed about cylindrical steel projectiles normal impact on PZT-5H piezoelectric ceramic composite target by using polyvinylidene fluoride stress test system and electrical output test system combining with one-stage light gas gun loading system. The experimental results show that the stress duration and peak stress are about $9~\mu \text{s}$ and 232 MPa, respectively, when the cylindrical projectile impacts on piezoelectric ceramic composite target at the impact velocity of 345 m/s. The outputs of current pulse peak, voltage pulse peak, and energy peak are 20 A, 734 V, and 11 mJ under the stress interactions of 200–300 MPa. At the near-impact stress conditions, the electrical output characteristics of piezoelectric ceramics are greatly affected by the load resistance. The output voltage pulse increases with the increasing of load resistance value, and the values of the load resistance have a significant effect on output energy; output energy conversion rate is up to 82% when the load resistance is $50~\Omega $ .

Based on the objective reality of gradient potential existence in spacecraft surface caused by charging particles in space-plasma environment or solar wind activities, electrostatic discharge of spacecraft with surface charging or deep dielectric charging would be induced by debris or meteoroids impact. To simulate the gradient potential on the spacecraft surface in the laboratory, spacecraft surface was segmented into different parts, which different spacing reserved in two adjacent surfaces was added resistance to create different potential surfaces, and the highest potential surface as a target in the segmented surface. Circuit system realizing different gradient potential, discharge test system, as well as ultrahigh-speed camera acquired system was built by ourselves; combining with two-stage light gas gun loading system, four set experiments have been performed about hypervelocity impact on 2A12 aluminum target with gradient potential. In the experiments, spacings of 2A12 aluminum target were the same among different potential parts in every experiment, and the spacings of four set experiments were 2, 5, 10, and 15 mm, and high-potential 2A12 aluminum as the target, respectively. The experiments were performed at the impact velocity of about 3 km/s and the incidence angles of 60° (between projectile flying trajectory and target plane). Voltage probes and current probes were used to acquire discharge voltages and currents during the process of the impact. The experimental results showed that the discharge induced by impact plasma was generated between high- and low-potential targets by forming a plasma discharge channel, the gaps with 2–15 mm can evoke discharge among different targets, and the variations of the discharge current along the high- and low-potential targets did not obviously. However, the discharge duration decreased with an increasing of distance between high- and low-potential targets at the near collision velocities and the same incidence angle of the projectile. The whole physical process of discharge had experienced four stages in general, which created by hypervelocity impact 2A12 aluminum targets with gradient potential. The first stage was plasma generated by hypervelocity impact, the second stage was complex mixed plasma including plasma generated by hypervelocity impact and discharge plasma induced by split targets with gradient potential, the third stage was discharge plasma induced by hypervelocity impact, and the fourth stage was the discharge between charging particles due to the reciprocating motion of charging particles in the electromagnetic field.

In order to reveal the temperature evolutionary characteristics of typical ferroelectric RAM (Random Access Memory) irradiated by femtosecond pulsed laser, a physical model of a typical ferroelectric RAM is established. The idea of using a continuous laser instead of a high-energy pulsed laser of the same energy on the laser transmission path was theoretically derived. The physical expression and thermal conduction model of the laser at different positions on the transmission path were simulated by Comsol Multiphysics simulation software. The melting and heat conduction process of the pulsed laser irradiating ferroelectric RAM are simulated, and the laser with different irradiation time is obtained. The temperature field distribution, melting and thermal conduction simulation parameters of the multi-layer target of the ferroelectric RAM are simulated by the femtosecond pulsed laser under the simulation conditions. The results show that the COMSOL Multiphysics simulation can accurately simulate the temperature field evolution of femtosecond pulsed laser irradiating ferroelectric RAM in the simulation experiment of single event effects. Heat radiation of the periphery of the ferroelectric RAM and the bottom of the heat transfer dominates. Thermal radiation transfers less energy to the pins and the periphery. After 5 s under the laser interaction, the temperature distribution of the ferroelectric RAM is stable. The heat conductivity, melting and convection characteristics of the ferroelectric RAM are basically consistent with the experimental results.

In view of the key problems of the discharge phenomenon caused by the impact of small space debris on the satellite's charged surface and the electromagnetic field induced entering the interior of the satellite after coupling through the aperture. In this paper, the characteristics of the coupling plasma, the plasma induced discharge and the propagation of the electromagnetic field induced by discharge through the aperture are studied by using the two-stage light gas gun loading system, the discharge charge monitoring system, the plasma diagnosis system and the electromagnetic testing system; Combined with the characteristic parameters of plasma inside and outside the Simulated satellite, the curves of discharge current and voltage, and the spectrum characteristics of electromagnetic radiation inside and outside the simulated satellite, the characteristics of electromagnetic field propagating into the Simulated satellite through the aperture under different potential on the surface of the simulated satellite are analyzed. The experimental results show that the characteristic parameters of the ionized plasma produced by the ionization of the target and the projectile splash increase with the increase of the surface potential of the target, and the ionized plasma determines the discharge characteristics and electromagnetic field characteristics; After the electromagnetic field generated by the impact side propagates through the aperture into the inner of the simulated satellite, the electromagnetic field in the simulated satellite appears signal attenuation in most frequency bands, but signal enhancement occurs in a few frequency bands; The main reason of electromagnetic signal attenuation is that the electromagnetic field directions at the edge of the aperture and the back of the target are opposite to that at the impact side; The enhancement of electromagnetic signals in some frequency bands is caused by the plasma entering the simulated satellite.

The theories of impact dynamics and adiabatic temperature change were adopted to investigate the ionization degree of the plasma generated by the 2A12 aluminum target during 2A12 aluminum projectile hypervelocity impact, and the radiant temperature was also estimated during hypervelocity impact. A two-stage light gas gun combined with the plasma characteristic parameters measured by a triple Langmuir probe was applied, and then the fitting relationship between the plasma ionization degree and the theoretical impact temperature as well as the fitting relationship between the maximum electron density and impact velocity were obtained with the aid of the theoretical derivation of the plasma ionization degree and the electron temperature and electron density extracted from experiments.

To researching the damage characteristics of typical logical chip modules in spacecraft due to plasma generated by hypervelocity impacts, we have established a triple Langmuir probe diagnostic system and a logical chips measurement system, which were used to diagnose plasma characteristic parameters and the logical chip module's logical state changes due to the plasma created by a 7075 aluminum projectile hypervelocity impact on the 2A12 aluminum target. Three sets of experiments were performed with the collision speeds of 2.85 km/s, 3.1 km/s and 2.20 km/s, at the same incident angles of 30 degrees and logical chip module's positions by using a two-stage light gas gun loading system, a plasma characteristic parameters diagnostic system and a logical chip module's logical state measurement system, respectively. Electron temperature and density were measured at given position and azimuth, and damage estimation was performed for the logical chip module by using the data acquisition system. Experimental results showed that temporary damage could be induced on logical chip modules in spacecraft by plasma generated by hypervelocity impacts under the given experimental conditions and the sensors' position and azimuth.

In order to study the ignition performance of self-powered overload igniter based on Lead Zirconate Titanate (PZT), shock simulation tests for different electro-explosive devices (EED) were carried out by using separated Hopkinson pressure bar to simulate overload environment. The output energy of PZT, temperature rise process of bridge wire in EED, initiation temperature of the detonator, ignition energy, and initiation delay of igniter are experimentally analyzed. The experimental results show that: 1) the matching degree between the resistance of EED and PZT plays a key role in the sensitivity of the igniter; 2) Whether the igniter can detonate successfully depends not only on the maximum overload but also on the overload action time; 3) During the ignition process, the initiating explosive starts to react before the bridge wire fuses; 4) There is a delay time from the output energy to the reaction temperature of the initiating explosive to the complete reaction of the initiating explosive, which is the main reason for the delay of the igniter.

Aiming at the evaluation model of Aluminum/Polytetrafluoroethylene (Al/PTFE) impact reaction energy release established by Ames R G, the factors that have great influence on reaction energy release, such as vessel wall energy absorption and ejected gas energy, are ignored in the model. In fact, the sum of the initial kinetic energy and the impact reaction energy release should include the increase of target internal energy, the enthalpy of gas products, the thermal radiation energy, the kinetic energy of gas products and the energy absorbed by the vessel wall. The evolutionary rules of each part energy are quantitatively evaluated by quasi-closed vessel experiments at different impact velocities combining with various measured methods such as overpressure sensor, high speed camera, instantaneous optical pyrometer and infrared thermal imager. The Ames R G model is modified based on the results of reaction energy release at different impact velocities, and a modified model of reaction energy release considering temperature is established. The results show that with the increase of impact velocity, the enthalpy of gas products and the energy absorbed by the vessel wall increase greatly. The energy absorbed by the vessel wall accounts for most of the projectile impact energy release. The impact reaction energy release of unit mass projectile increases with the increase of impact velocities. When the impact velocities are in the range of 389–509 m/s, the increase of reaction release energy is significantly lower than that of 509–596 m/s. The modified model considering energy loss can be used to quickly evaluate and characterize the reaction energy release characteristics of active materials under impact load.

To investigate the relationship between stress wave propagation and the plasma discharge generated by a projectile high-velocity impact on solar array with 2A12 aluminum substrate structures at the incidence angle of 60°. Three sets of experiments about stress wave propagating and plasma discharge in composite structure of solar array have been performed by taking advantage of PVDF (polyvinylidene fluoride) film sensor, plasma characteristic parameter diagnostic system, discharge measurement system and two-stage light gas gun loading system established by ourselves. Experimental results showed that the duration of stress wave was about 30±5μs, and maximum stresses are about 1400±200MPa in experiments. Furthermore, the discharge phenomenon did happen and the duration of discharge current was also different in solar array at the different impact velocities. The basic consistency between stress wave propagation and discharge duration is also confirmed by experiments.

Damages by a laser to materials are mainly caused by thermal and dynamic effects; such effects are referable for evaluating damage by a laser to the optical lens and the design of a laser system. We have designed several independent laser–material interaction measurement systems and carried out experimental research based on them. The results show that the laser plasma oscillation frequency is 500 Hz and accompanied by discharge phenomena. The average pressure stress on the material is 1.1 GPa; then it attenuates to the Lamb wave; and the surface coating of the lens reduces the radius of the heat-affected zone to one third of that without film.

Plasma-induced discharge is an important effect on the solar array of orbiting space vehicles subjected to hypervelocity impact, which will pose a serious threat to the power supply system of spacecraft. The paper investigates experimentally the process that the projectile in various impact velocities and incidence angles impact on solar array with sandwich structure comprising of a coverglass, a silica gel and a 2A12 aluminum liner at the different positions. The electron temperature and density of the plasma were diagnosed by applying in independent-constructed Triple Langmuir Probe diagnostic system, meanwhile, the charging and discharge test system were also constructed by ourselves. Three sets of experiments have been performed by two-stage light gas gun loading system and related measurement system. Especially, residual velocity was measured when projectile pierced through the solar array with composite structure. Experimental results revealed the discharge causes based on stress wave theory, and the discharge current characteristics of a primary and a secondary discharge of solar array induced by hypervelocity impact were given through hypervelocity impact experiments. Finally, it will provide a valuable benchmark for the construction of solar array against space debris.Plasma-induced discharge is an important effect on the solar array of orbiting space vehicles subjected to hypervelocity impact, which will pose a serious threat to the power supply system of spacecraft. The paper investigates experimentally the process that the projectile in various impact velocities and incidence angles impact on solar array with sandwich structure comprising of a coverglass, a silica gel and a 2A12 aluminum liner at the different positions. The electron temperature and density of the plasma were diagnosed by applying in independent-constructed Triple Langmuir Probe diagnostic system, meanwhile, the charging and discharge test system were also constructed by ourselves. Three sets of experiments have been performed by two-stage light gas gun loading system and related measurement system. Especially, residual velocity was measured when projectile pierced through the solar array with composite structure. Experimental results revealed the discharge causes based on stress wave theory, and th...

Due to the actual situation of spacecraft surface’ charging, such as convex corners, weld line, whalebone and a multiple-interfaces with different materials, all these are main factors leading to uneven charging of spacecraft surface, even creating gradient potential. If the charging spacecraft surface is impacted by debris or micrometeor, discharge effect induced by impacting will pose a serious threat to spacecraft in orbit. So realizing spacecraft charging surface with different potential differences and grasping discharge characteristics are a decisive importance at the different experimental conditions in laboratory. To simulate the spacecraft surface with a gradient potential in laboratory, spacecraft surface is split into different parts, which different gaps reserved in 2 adjacent surface is added resistance to create different potential surfaces, and the high potential surface as a impact target in the split targets. Charging circuit system realizing different gradient potential and discharge test system are built by ourselves, combining with two-stage light gas gun loading system, six sets of experiments have been performed about hypervelocity impact on 2A12 aluminum split targets with gradient potentials. In the experiments, gaps of 2A12 aluminum target are the same among different parts in every experiments, the gaps of the split targets are 2mm, 3mm, 5mm, 7mm and 10mm in the experiments, respectively. And the applied voltage is 300V in all the experiments and high-potential 2A12 aluminum plate as the impact target. The experiments have been performed at the impact velocity of about 3km/s and the incidence angles of 60o and 90o (between projectile flying trajectory and target plane), respectively. Voltage probe and current probes are used for acquiring discharge voltages and currents during the process of the impact. The experimental results showed that the discharge induced by impact plasma were generated among high and low-potential target by forming a plasma discharge channel. With the increasing of the gaps among the high and low-potential targets, the peak values of the discharge current decreased first then increased. When the gaps of split targets reached a certain value, the peak values of the discharge current decreased again. Meanwhile, the gaps among high and low-potential targets was 5mm, the peak value of the discharge current was the smallest. With the increasing of the gaps among the split targets, a primary discharge duration also increased. However, when the gaps among the split targets were greater than 5mm, increasing trend of discharge duration would slow down. When the gaps among the split targets were greater than 7mm, there was a secondary discharge phenomenon, and the physical explanations were given about the influence of different gaps among the split targets on the discharge effects created by hypervelocity impact.