强动载荷作用下压阻式微型加速度计的响应特性及规律研究

Penetration deceleration measurements based on the high-g micro-piezoresistive accelerometers (MPAs), not only contain the rigid acceleration components caused by the deformation of sensing elements of MPAs under inertia force when treating the projectile as a rigid body, but also couples the high frequency accelerations induced by the structural impact response, caused by the stress wave propagation in the projectile under intensive dynamic loadings. The coupled deceleration is an important factor which influences the accuracy and reliability of the original deceleration measurements based on the MPAs. But until now there is no uniform criteria and method to guild how to separate the rigid deceleration signals from the original deceleration measurements, which restricts the wide applications of high g MPAs.. To solve this problem, in this proposal, the combination method of theoretical analysis, numerical simulation and experimental study is used. The law of projectile structural impact response and the prediction model of deceleration during the penetrating process are built. The model of the MPA measurement system is created, and then the structural impact response in projectile and the deceleration results with various amplitude and frequency ranges are applied as inputting conditions in the model, and the mechanical response and dynamic characteristics of the MPA measurement system are studied. The measured method by the use of MPAs and strain gauges, through the test recorder of multi-channels, is proposed. Projectile impact/penetration model tests are then conducted. In the tests, the acceleration and the strain response in different locations of the projectile bodies are measured. The test results are analyzed, and the deceleration data-processing results are compared with the corresponding experimental results. The influence law of the projectile structural impact response on the measurement of decelerations by MPAs and its mechanism are clarified. The research findings can provide technical foundations for building the criteria and method for decoupling the deceleration signals into rigid body decelerations and structural response induced deceleration signals, and improving the accuracy of penetration trace analysis.

基于高g值压阻式微加速度计测到的弹体侵彻过载，不仅包含视弹体为刚体时惯性力作用下传感器敏感元件变形产生的刚体过载，也耦合了强动载作用下弹体结构冲击响应产生的过载，是影响基于加速度计获取真实可靠的实测过载的重要因素，且如何从实测过载中分离出刚体过载尚无定论，这些均限制了高g值压阻式微加速度计的应用。本项目拟结合理论、数值和试验研究，获得侵彻过程中弹体结构冲击响应规律，提出过载预测模型；建立压阻式微加速度计测试系统的模型，将弹体结构冲击响应和过载信号作为输入条件，分析其力学响应和动态特性；结合压阻式微加速度计和应变片技术建立多路弹载存储测试系统，开展弹体撞击/侵彻试验，获得弹体不同部位的加速度和应变响应；分析实测过载和应变，比较过载处理结果与相应实测值，以完善理论和数值模型；阐明弹体结构冲击响应影响过载测试的机理与规律。预期成果为建立过载信号的解耦原则、提高侵彻弹道分析的可靠性等提供技术支持。

为准确测量侵彻深度以达到精确引信，目前常采用弹载加速度计记录侵彻过程的加速度信号，通过对实测信号的积分来获取弹体的实时运动情况。但在已有测试数据中发现，加速度计记录到的过载曲线一次积分与二次积分后得到的值与实际速度值、位移值相差较大。因此研究动载荷下弹体的结构响应特性，对找出实测信号偏离真实值的原因，实现准确引信具有重要意义。. 本项目首先将传统的霍普金森压杆装置与低速侵彻实验结合在一起，将长杆弹体做成三段式内有空腔的分段弹体，通过硬回收法得到分段弹体过载信息。并且选取牛皮纸作为低速侵彻时的靶体。通过对分段弹体加速度信号的一次积分与二次积分所得速度和位移与外部测量手段所测得的速度和侵彻深度数据进行对比研究，可确定影响过载测量准确性的因素。该装置能保证分段弹体低速侵彻实验的顺利完成，并能保证实验的可行性及重复性。从已取得的实验结果表明在弹体被低速撞击与自由飞行过程中应力波对加速度信号采集存在一定的影响，该影响会造成通过一阶积分运算所得到的速度值存在明显的二次升高。 . 然后通过数值模拟的方式对分段式弹体侵彻纸靶实验的过程进行模拟，辅以理论分析与实验数据进行支撑。从加速度计的校准、弹体的发射、弹体侵彻过程及数据处理四个方面进行分析。对利用霍普金森压杆改造的装置为分段式弹体提供加速度激励的过程进行数值模拟研究，分析在不同撞击速度下分段式弹体可获得的速度、弹体内外部不同部位的加速度时程曲线及弹体内部应变时程曲线等，发现了基于分段式弹体这一特殊结构的响应规律。在弹体侵彻模型中，根据靶体的变形情况，选择采用 Recht-Ipson公式处理剩余-初始速度，并得到特定弹靶系统的弹道极限；深入分析了弹体内质点过载信号的变化规律，探讨了应力波的传播对弹体过载的影响，对加速度计在弹体内的安装位置做出了建议。在此基础上，总结现有实测加速度信号在行程计量中的处理方法，并通过低通滤波的方式对冲击载荷下的加速度信号进行了有效的处理，也针对侵彻纸靶的过载信号提出新的滤波方向。. 最后运用ABAQUS软件研究低速状态下分段式长杆弹侵彻铝靶板的响应特性。 分析速度对弹体各个部位的过载与响应特性的影响；得出不同速度下各段弹体的过载规律；得出弹腔内外部的应力特性。为弹体侵彻的引信设计与弹载记录仪的最佳安装位置提供参考。

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