跨介质飞行器水下发射或高速入水过程中,空泡在壁面溃灭会产生较大压力脉冲,使舱体由于局部外压发生变形,由此引起的局部应变会成为载荷测量中截面应变的干扰应变,对截面载荷测量产生较大影响.为了从应变桥路中消去壳体局部弯曲应变的影响,基于壳体受力模式分析,本文提出在舱段表面打孔将应变片直接贴在中面的方法,以期消除局部弯曲应变的影响.并通过有限元仿真方法确定打孔及虚拟电桥应变片位置,消除了局部高强度外压对弯矩桥路应变的影响;提出了基于均匀外压标定得到环向非均布外压影响的耦合灵敏度标定方法并通过有限元验证了该方法的合理性.地面验证试验表明,考虑外压耦合灵敏度,在保证弯矩识别精度的前提下,轴力识别误差明显降低.

地面辐射热试验是考核高速飞行器结构力热性能的主要手段.针对高速飞行器结构力热试验需求,介绍了辐射热试验模拟方法,分析了模拟机理和有效性,研究了载荷施加、参数测试,以及环境效应等影响模拟有效性的因素,并提出了需要重点研究的问题和相应解决方案.通过上述研究,能够提高对飞行力热环境的模拟准确程度,进一步提升高速飞行器辐射热试验的有效性和适用性.

爆炸分离冲击是航天器所经历的最严酷的力学环境之一,为了避免一些箭载仪器设备或者结构在飞行中损坏,因此需要进行爆炸分离冲击环境试验.本研究针对航天产品爆炸分离冲击环境宽频响、高作用幅值的特点,提出了非接触式电磁激励响应板方式的爆炸分离冲击环境模拟试验方法,建立了电磁激励系统多物理场耦合模型,开展了电磁激励爆炸冲击环境模拟的试验研究,获得薄板在电磁加载过程中洛伦兹力和薄板响应的关系,揭示了采用该方法进行冲击环境预示与控制的机理,为实现电磁激励载荷作用下的结构响应的可预测提供了研究基础.

Noise characteristic is one of the important factors to be considered during the design of a launch vehicle system. In this paper, the acceptance conditions for the external noise environment of the instrument cabin are given based on multi-source data, including the measured data of the launch vehicle lift-off noise, the mechanical environ-ment of the launch vehicle equipment, and the external noise environment of the instrument cabin deduced from empirical formula. Then an acoustic and vibration transfer model is established based on the response data of the in-strument equipment used to conduct measurements in the noise test reverberation room. By using an external noise environment and a transfer model, the response of the instrument and equipment for the acceptance condition can be obtained. The acoustic and vibration prediction technology introduced in this paper can provide technical support in the environmental prediction analysis of heavy launch vehicles for the future.

This paper proposes a numerical solution method for upper bound shakedown analysis of perfectly elasto-plastic thin plates by employing the C $$^{1}$$ natural element method. Based on the Koiter’s theorem and von Mises yield criterion, the nonlinear mathematical programming formulation for upper bound shakedown analysis of thin plates is established. In this formulation, the trail function of residual displacement increment is approximated by using the C $$^{1}$$ shape functions, the plastic incompressibility condition is satisfied by introducing a constant matrix in the objective function, and the time integration is resolved by using the König’s technique. Meanwhile, the objective function is linearized by distinguishing the non-plastic integral points from the plastic integral points and revising the objective function and associated equality constraints at each iteration. Finally, the upper bound shakedown load multipliers of thin plates are obtained by direct iterative and monotone convergence processes. Several benchmark examples verify the good precision and fast convergence of this proposed method.

针对航天航空发动机转子叶盘失谐振动研究需求,提出一种行波激励模拟试验系统,可在转子叶盘保持静止的状态下,有效的模拟其在真实旋转工作状态时所承受的阶次激励.对该系统进行了误差仿真分析,表明该系统可在定量层面上完成转子叶盘等循环对称结构各种振动现象机理认知、方法验证的试验实践,也为评定转子叶盘失谐振动研究试验系统性能提供了一种手段.

提出了航天结构振动频率管理方法和流程,对流程中涉及的航天结构管理对象明确与分类方法、激励源频率特征获取、动力学传递特性获取、改进措施方法等进行了总结和说明.提出了振动频率管理原则并进行了机理分析,给出了几个典型航天结构振动频率管理及特性获取要求.对航天结构的频率管理设计、频率耦合检查以及相关标准规范的制定均具有重要的指导意义.

根据端部带质量和弹簧约束悬臂梁的特征值条件,提出了一种特征变换方法,获得了带约束悬臂梁广义质量和振动响应的解析解.通过分析根部弯矩、端部位移、速度和加速度放大系数的变化特征可知,端部弹簧的刚度对静态和一阶载荷响应有明显的影响,减载设计时可以放宽对端部质量的限制,载荷响应分析阶次介于速度和加速度的分析阶次之间.提出的特征变换方法可应用于求解其他载荷分布、边界条件和端部约束悬臂梁的振动响应解析解.

石英灯辐射加热是目前飞行器典型整结构热试验使用最广泛的一种加热方式,本文围绕飞行器辐射加热面的工程测量需求,考虑DIC方法的原理和典型热试验的实际工程环境,分析了应用高温DIC测量方法研究石英灯辐射加热面变形信息的技术难点和误差来源,从制作高质量的标准高温散斑场和消除长波段辐射光干扰方面入手,提出了一种基于石英灯正面加热的高温DIC方法改进方案.最后设计C/SiC小板缝隙试验,结合石英灯辐射热流模型,优化设计满足DIC测量窗口的石英灯加热器,成功测量缝隙尺寸随温度增加的变化量,证明了基于石英灯辐射正面加热的高温DIC方法改进方案的可行性.该方法可以为研究结构或重要部件地面热试验中的局部变形、位移、缝隙等测试问题提供解决方案,对未来新型飞行器的试验研究具有非常高的实用价值.

本文采用自主研制的光纤高温应变复合传感器对碳基复合材料结构样件在常温～810℃范围内的高温应变测试特性进行了研究.在马弗炉内对两件碳基复合材料结构试件分别进行三次常温～810℃重复加热实验,高温应变热输出测试结果具有很好的重复性.在万能试验机上,在800℃高温环境下对碳基复合材料结构试件进行了拉伸实验,光纤高温应变复合传感器的测量值与高温引伸计的测量值具有较好的一致性.与此同时,在本文实验结果中,光纤高温复合传感器测试结果的跟随性、平滑性要优于高温引伸计的测试结果.

针对某型制动盘系统在制动刹车过程中出现断裂失效的情况,本文对制动盘系统的动特性进行了较为详细的研究.首先建立了该型轮装制动盘系统的有限元模型,依据模态试验结果对计算模型进行修正;接着采用复特征值法计算了该型轮装制动盘系统的尖叫模态频率;然后采用时域响应分析法计算了制动盘系统的敏感频率及螺栓动响应,对比两种方法计算得出的频率,最大误差为1.83%,有效验证了模型的准确性.另外通过分析可知在特定运行环境下,制动盘系统在摩擦力作用下发生尖叫,即制动盘系统自身模态发生耦合.最后采用复特征值法研究了摩擦系数及闸片刚度与轮装制动盘系统尖叫模态频率的关系,研究表明,闸片刚度处于160GPa~180GPa、摩擦系数大于0.34时,制动盘系统产生尖叫,对该型制动盘系统设计改进具有一定的工程指导意义.

The pipelines of aerospacecrafts have characteristics of light and thin structures, severe mechanical environment, high operating stresses and easy to cause low cycle fatigues, and they have broken down in flight for many times. With the development of aerospacecrafts for lightness, reuseable and high reliability, the pressing requirements of pipelines change from environmental adaptability qualitative check to dynamic strength quantitative evaluation. This article firstly introduces the fundamental principles and applications of dynamic load analysis methods for pipelines base on the Miles formula, the modal root mean square (RMS) value, etc., and uses it to guide the dynamic design of pipelines. Then basing on engineering practices, it summaries the theoretical methods and technical key points of the Steinberg fast assessment and the frequency domain fatigue analysis base on statistics model, etc., which are always used in the dynamic strength analysis of pipelines. Finally, combining with the investigation status of design, analysis and test for pipeline dynamic strength in aerospace field, it outlooks the engineering and scientific problems needed to be studied further.

In this paper, we summarized the development stage and the classification of the test of mechanical environment experiment, discussed the promotion of experimental technology by the flight defeat and the role and necessity of researching the test. At the present, the current situation and shortcoming of domestic engineering, emphasizing the importance of mechanism to obtain the response characteristics of experimental development, proposed physical test and experimental model to establish, calculate and analyze the experimental data together given the white box test development.

in this paper, failure analysis of aerospace production in the dynamical field was summarized, the disposal process and method was briefly explained, also varies of vibration and method of vibration control was summarized. The analysis was given about the status and technical development.we think control coupling vibration and analysis of dynamic strength should be the the development direction of structure dynamical technique.

针对现阶段航空航天管路结构环境试验存在的问题,研究了管路结构在预载荷及随机振动试验条件作用下的动强度特性的分析方法,明确了由预载荷引起的微分刚度、预应力在结构振动响应计算及疲劳寿命分析时的区别及处理方法,提供了一种可定量预估管路结构在多种试验环境作用下随机振动疲劳损伤的分析方法,该方法解决了真实环境试验条件如何表示预期使用环境的问题以及真实环境试验条件与预期使用环境不一致对管路结构动强度造成的影响如何进行评估的问题.通过对管路结构的仿真,分析了管路的动强度薄弱点以及剩余强度系数和疲劳寿命,验证了该方法的有效性,从而为分析管路结构在真实使用过程中的环境适应性以及可靠性提供了一定工程指导.

High quality dynamic model of aerospace structural could be obtained through hard effort, such as reasonable FEM model、reliable experiment data and efficient model updating method. This paper is about the technology of systemic method of dynamic model updating. A integrated flow was proposed, including modeling-pretest-modal data assessment and model updating technology. Firstly, a method on how to model soft connect structural was present. Then, different methods of pre-test were compared, and general strategy of modal experiment result was obtained based on literature survey and engineering experience. Lastly, model updating method under multi state and multi object condition was studied, and one of smart optimization algorithm, namely GA, was studied, and hierarchical model updating ideology was adopted at the same time. Finally, a single state-multi state model updating system was developed and applied to a missile’s dynamic model.

Orthogonal measure points are not available, sometimes, when measuring dynamic load in flight for launch vehicle. In order to obtain sectional load of a launch vehicle, a new kind of strain measure point placing method is proposed. Non-orthogonal measure points are taken to obtain sectional load. Three sensitivity scaling means are presented and the methods of how to calculate the sectional load are given also. Static experiment is done, and linear relationship is clear between load and strain. That is to say that the method is good enough to be used in structural load measurement. The proposed method is applied in load measurement during flight. The difference between the three load calculating methods is analyzed approximately.

This paper research the damage of the instrument in the noise environment, explain the problem that the pin of PCB fracture in the test of noise vibration with high level, The noise excitation and laser vibration technique, sound transfer examination, the modal test and finite element calculation have been analyzed, and worked out the distribution of dynamic stress of the pin. And in the paper, the result that the failure mode and life time getting form the assessment according to the S-N curve is coincided with test was got, which shows that the analysis method is effective, and affords theoretical support for the mechanism research of the fault phenomenon and its improvement,continuation the method of reliability research in instrument.

In light of the cracking phenomenon of the solder joints on CQFP package circuit board under the cycle temperature load, this paper analyzes and calculated it according to the solder creep constitutive model and the method of finite elements, then find out that the maximum creep is located at the corner solder wire on the surface, which is coincided with the experimental phenomena, and so is the result of the life assessment of structure under the strain fatigue model. The methods and results of this paper provide the research of fault mechanism and its improvement with theory and method supports.

Basing on the FEM and theory methods, Thermo-fatigue life of LCCC electronic packaging structure is investigated. The analysis outcomes show that the Fatigue life predicated by FEM is associated with the result of the theory method. The techniques explored by this paper are extended conveniently to evaluate thermo-fatigue life for other electronic packaging structures.