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用于高性能雷达罩的树脂基体的研究 总被引:1,自引:2,他引:1
介绍了三种高性能雷达罩用的改性双马来酰亚胺树脂体系4501A、4501B和4503。研究了树脂,固化树脂及其玻璃布增强的复合材料性能,4501A和4501B可适用于热压成型,Tg分别为274℃,268℃;为10GHz下tgδ分别为0.0117和0.0108,4501B树脂制作的预浸料具有更优异的铺覆性。 相似文献
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马明臻%曾松岩%张二林%周彼德 《宇航材料工艺》2000,30(1):59-63
采用真空热爆加压法(简称VTEP)工艺制备了高粒子含量TiCp/2024复合材料。通过数据采集器记录了不同铝含量时热爆反应的时间--温度曲线;通过XRD分析了TiCp/2024复合材料的相组成;用SEM和TEM观察了TiCp/2024复合材料的显微组织、微观结构和断口形貌。结果表明:VTEP工艺可以获得颗粒细小圆整、分布均匀、致密的高颗粒含量TiCp/2024复合材料。 相似文献
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雷达罩应用5258树脂基复合材料的试验研究 总被引:1,自引:0,他引:1
通过试验研究了雷达罩所用主要材料5258环氧树脂、预浸料和复合材料制备方法,进行了这些材料及结构的拉伸、弯曲、剪切和介电常数等性能的测试,结果表明5258树脂基体制备的复合材料均具有良好的力学和电学性能,能够满足雷达罩的设计要求。 相似文献
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采用新型催化剂、增韧剂制得了一种改性氰酸酯树脂,对新型改性氰酸酯树脂的工艺性、耐热性、力学性能进行了评价,并对其复合材料的介电、力学性能进行了研究。结果表明新型改性氰酸酯树脂具有良好的工艺性,适合热熔法制备预浸料;树脂及其复合材料的力学及介电性能优良,可在180℃下使用,适合高性能透波材料和高频电路板使用。 相似文献
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复合材料层合板抗冲击损伤的参数表征 总被引:1,自引:0,他引:1
研究了铺层方式为[02/902/452/-452]s的航空用碳纤维增强树脂基复合材料(CFRP)准各向同性层合板低速冲击引起损伤的表征问题。通过落重冲击试验引入损伤程度D表示材料低速冲击后材料参数的变化大小,通过准静态球面弯曲试验提出复合材料层合板抗冲击的三种表征参数:层内开裂临界能E1c、层间开裂(分层)临界能E2c、分层扩展阻力R. 相似文献
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研究了铺层方式为「02/902/452/-452」S的航空用碳纤维增强树脂基复合材料(CFRP)准各向同性层合板板速冲击引起损伤的表征问题,通过落重冲击试验引入损伤程度D表示材料低速冲击后材料参数的变化大小,通过准静态球面弯曲线试验提出复合材料层合板抗冲击的三种表征参数:层内开裂临界能E1c,层间开裂(分层)临界能E2C,分层扩展阻为R。 相似文献
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歼七系列机用雷达罩夹玻璃布蜂窝芯在制造过程中常出现蜂格粘连以及脱层现象。从材料、工艺、设备等方面进行了分析,原因是设备选用不当、工艺参数不适合。选用土推式液压机,调整加压点生产出合格的蜂窝芯。 相似文献
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改性BMI/DPA和CTBN增韧环氧树脂的温度,力学性能及本构关系研究 总被引:2,自引:0,他引:2
研究了CTBN增韧环氧树脂和烯丙基双酚A改性双马树脂(BMI/DPA)在不同温度和加载速率下的拉伸和压缩力学性能。对于CTBN 增韧环氧树脂,材料在动态拉伸情况下,随着应变率的增大,材料由韧变脆,模量升高,断裂伸长率下降;在压缩情况下,弹性模量和屈服应力均随着加载速率的增大而增大。对于改性双马树脂,在室温的动载压缩下,其模量E和屈服应力σy均基本上与lnε呈直线关系增大,并给出了该树脂在不同加载速率下的压缩应力应变曲线。计算了两种材料的温度敏感度和加载速率敏感度以及温度和应变率对两种树脂材料屈服应力影响的本构关系。 相似文献
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GAO Jian-ping 《中国航空学报》1999,12(4):217-221
Gain-scheduling has got its wide applications in modern flight control, in which control gains are scheduled with variables such as dynamic pressure and Mach number, to meet dynamic response requirements in different flight conditions. Classical gain-scheduling approaches may result in some problems, which can not guarantee global robustness and stability in transitions of different flight conditions. Gain-scheduling problem is systematically investigated from robustness point of view in the paper. Detailed procedures for gain-scheduled controller to achieve both robustness and stability performance are given and applied to a typical flight control system. For switching stability problems of different flight conditions in flight control systems, a new approach is proposed, in which different flight conditions are reduced into a parameter varying plant using interpolation firstly, and then parameter-varying controller design goes next. Though interpolation errors may exist, the robust parameter varying controller design can compensate for those uncertainties and errors, and finally achieve good performance of robustness and switching stability during transitions. Illustrative simulation at last shows satisfactory results. 相似文献
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Nonlinear sliding mode predictive controller is designed for a class of nonlinear system with unmodeled dynamic characteristics and nonlinear term. The method is based on nonlinear optimal predictive control. The variable structure control law minimizes the quadratic index of a predictive sliding mode, which contains the cost function of control preventing the control effect from saturation for in most practical implementation the control inputs are bounded by physical constraints and energy constraints. According to the immeasurable states, the variable structure observer for nonlinear systems is adapted. The variable structure system method is apt to the realization of observer with variable parameters and uncertainty. The proof shows that the states of the observer asymptotically convergence to the real states of the system although it is of uncertainty and nonlinear terms. Finally, the digital simulation results prove the effectiveness of the proposed method. 相似文献
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周光明%梁中全%赵谦 《宇航材料工艺》2004,34(5):21-25
研究了C/G(碳/玻)层内混杂单向复合材料的力学性能,对其拉伸、弯曲、层间剪切、振动阻尼等性能进行了实验研究,并与同样铺层的纯C、G复合材料进行了对比分析。研究表明:C/G层内混杂复合材料可充分利用C、G纤维的各自优点,改善单一材料的模量、强度、断裂韧性、振动阻尼特性等力学性能,模量预测值与实验值较为接近,强度因影响因素较多,二者存在一定的差异,力学性能随C、G体积分数的变化符合混合律,说明了实验方法的合理性。通过C、G相对体积分数的合理设计可满足结构的实际要求。 相似文献
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GAO Jian-xin 《中国航空学报》1999,12(4):197-204
The transient behavior of isotropic and homogeneous plates has been a subject of interest. The present investigation is concerned with the large deflection transient analysis and control of plates with piezoelectric sensors and actuators under applied transverse loads. In this paper, the incremental finite element equations considering the geometric nonlinearity of piezoelectric smart structures are developed based on Total Lagrange approach by using the virtual velocity incremental variational principles. A four-node Mindlin plate element with reduced and selective integration is adopted. The resulting increment equations are solved by using Newmark's direct integration approach. Transient response of plates with piezoelectric sensors and actuators subjected to transverse dynamic loading is investigated. The active damping is introduced on the plates by coupling a negative velocity feedback algorithm in a closed control loop. The numerical results show that piezoelectric actuators can produce significant damping and suppress transient vibration effectively. Finally, the effects of the number and locations of the piezoelectric actuators on the control system are also investigated. 相似文献
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This paper presents the results of finite element analysis of rubber structures based on novel strain energy functions stemming from the representation theorem of tensorial function. The stress tensor is represented by Taylor expansion, using the representation theorem of tensorial function of a single tensorial argument for all terms in each order of the expansion. The scalar-valued coefficient functions of the theorem are represented by the integrity bases of the strain tensor and material constants to be determined by experiment. The computer implementation of the new constitutive laws has been verified by comparing the FE results with analytical solutions. A complicated structure of rubber bearing was analyzed. The FE results show good correlation with experimental data. 相似文献
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采用"化学气相渗透+先驱体浸渍裂解"(CVI+PIP)混合工艺制备固体冲压发动机用C/C-SiC复合材料喷管内层,综合考查复合材料的微观结构、弯曲性能和抗烧蚀性能以及固冲发动机C/C-SiC喷管内层水压和点火实验。结果表明:复合材料的弯曲强度达到197 MPa,且断裂破坏行为呈现典型的韧性模式;复合材料具有优异的抗氧化烧蚀性能,氧化烧蚀200 s后线烧蚀率仅为0.0063 mm·s-1;研制的C/C-SiC复合材料构件的水压爆破压强为6.5 MPa,表明构件具有良好的整体承载能力;C/C-SiC复合材料喷管内层高温综合性能通过了固体冲压发动机点火实验考核。 相似文献
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RESEARCH OF THE SWITCHED RELUCTANCE STARTER/GENERATOR SYSTEMS 总被引:5,自引:0,他引:5
This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine. 相似文献
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电阻渐变型结构吸波材料的研究与发展 总被引:15,自引:3,他引:12
结构吸波材料的发展建立在先进复合材料发展基础之上,融受力与吸波为一体,将新的吸波机制(如电阻片、电路模拟、手征媒质等)引入到结构吸波材料的研制中,可制备全新的结构吸波材料.电阻渐变型结构吸波材料具有优良的电结构可设计性,通过控制材料的类型(电介质或磁)、厚度、损耗系数及阻抗等,能够使雷达吸波材料具有宽频吸收效果,并可根据不同部位选择不同的结构形式,具有广阔的应用前景. 相似文献
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This paper holds that the key to improve the hitting rate of air-to-air missiles is to decrease the error of initial alignment of the inertial navigation system. Therefore, considering that the alignment should be completed within a specified short time, this paper presents the theory of transfer alignment and the computing way of accuracy in an air-to-air missile, where the platform inertial navigation system, or master INS, is adopted on aircraft, and the strap-down inertial navigation system, or slave INS, is used on missile. It emphasizes the idea of transfer alignment, that is, calibration of the slave INS is based on the master platform, and adopts a reasoning measure to deal with the installing-error-angle. And it is proved by simulation that the transfer alignment can be quickly achieved. 相似文献