固体火箭发动机壳体及裙部的应力分析

考虑到纤维缠绕壳及裙部结构特点，对筒体采用有矩理论的分析方法，对封头部分，引用Ｅ．Ｍｅｉｓｓｎｅｒ变量为基本未知量，导得分析总是的两个基本控制方程，采用样条配点法求解。将两部分的解联立起来，可提供符合结构实际情况的计算结果。     

固体火箭发动机燃烧室壳体纤维缠绕模具设计

介绍一种固体火箭发动机燃烧室壳体纤维缠绕芯模的设计.这项工作的目的在于提供一种可重复使用的纤维缠绕芯模.它采用的方法是钢模分瓣法.这种芯模的关键技术是芯模的组装和脱模.这项工作的意义在于提高纤维缠绕固体火箭发动机燃烧室壳体的比强度,节约生产成本,提高工作效率.     

固体火箭发动机复合材料壳体承载力分析

为了提高固体火箭发动机(SRM)的外载荷承载能力,研究了其复合材料壳体的失效机制,提出了复合材料壳体的增强改进结构形式。通过提高复合材料外缠绕层的轴向刚度和横向弯曲刚度,使得连接区域内的内、外缠绕层的轴向变形相协调,改善了内、外缠绕层的轴向承载分配,使增强改进后的复合材料壳体结构的承载能力提高了124%,而结构质量增加低于10%。研究结果表明: SRM复合材料壳体承载能力的关键因素是连接区域内复合材料内、外缠绕层的刚度匹配设计,只有保证连接区域内的刚度匹配和位移变形相协调,才能充分发挥复合材料壳体的承载能力。     

固体火箭发动机壳体低压力开裂原因分析

通过化学成分分析、力学性能试验、断口宏微观分析等方法,对某固体火箭发动机壳体水压试验低压力开裂的原因进行了分析。结果表明:该发动机壳体开裂的性质为低应力下的韧性断裂,开裂的主要原因是发动机壳体外表面局部区域存在微裂纹缺陷。     

固体火箭发动机粘弹动力学研究

用有限元法通过复特征值分析,建立了固体火箭发动机振动特性分析的复特征值法和直接频率法两种计算模型。用其计算固体火箭发动机弯曲振动的固有频率、振型及阻尼、并进行试验验证,得到了较满意的结果。     

固体火箭发动机声能共振规律试验研究

从固体火箭发动机声不稳定燃烧的声学特性出发,以声学激励作为扰动并提供能量,从声学响应角度评估发动机的稳定性,建立了探究固体火箭发动机声能共振规律的试验方法并搭建了试验系统,对于不同发动机结构开展了试验,结果表明试验系统可以表征声不稳定燃烧的声学特性;不同前封头结构声腔的各阶振荡频率基本相同,对于第一阶压力振荡,带有凹腔...     

一种通用型固体火箭发动机装药燃烧模拟办法

本文致力于找到一种新型具有通用型固体火箭发动机装药的燃烧模拟方法。本文选用的装药模型是星孔装药。保存数据时,我们选用链表结构,更方便地实现点的删除,最终生成了星孔装药的燃烧曲线。     

专利介绍（二）——专利名称：一种炮弹用固体火箭发动机药柱的装填工艺

一种炮弹用固体火箭发动机药柱的装填工艺，将发动机药柱的贴壁浇注工艺和自由装填工艺的优点有机地结合起来的，通过在发动机药柱侧面与发动机壳体之间注入填充剂，解决了贴壁浇注工艺和自由装填工艺分别生产的固体火箭发动机药柱在炮射过程中抗过载能力低的技术问题，使发动机具有一致性好、可靠性高、装药量大的优点。     

固体火箭发动机喷管型面的研究进展

固体火箭发动机喷管型面设计直接关系到喷管效率和推力大小,是喷管设计中的重要研究课题。本文从喷管型面设计方法、型面参数优化和喷管流固热耦合分析等方面综述了国内外对固体火箭发动机喷管型面的研究进展。总结出了直接优化方法、特型喷管的设计方法、六次Bézier曲线、双三次样条曲线构造扩张段型线和B-Spline曲线和特征线方法等喷管型面的设计方法,并介绍了计算流体动力学(CFD)和随机优化方法在固体火箭发动机(SRM)设计优化中的运用。分析了固体火箭发动机喷管涉及到的流固热耦合问题,并结合文献介绍了经典CFD算法、CBS有限元算法和格子波尔兹曼在研究流固热耦合问题上的运用。     

Al/CFRP混合薄壁结构耐撞性能可靠性优化设计

轻量化是实现汽车产业向安全、节能、环保发展的一个重要途径。Al/CFRP（carbon fiber reinforced plastic,碳纤维增强复合材料）混合材料能够在提升轻量化效果的同时兼顾材料成本和结构耐撞性能。为探索方形截面Al/CFRP混合薄壁结构的最佳组合方式,首先,制备了Al方管、CFRP方管和Al/CFRP混合方管,并开展准静态压溃实验。然后,建立能够精确模拟Al/CFRP混合方管压溃响应的有限元模型。最后,将试验设计方法、代理模型技术、多目标优化算法和蒙特卡罗模拟技术相结合,对Al/CFRP混合方管分别进行多目标确定性与可靠性优化设计,并对效果较好的可靠性优化解进行仿真验证。准静态压溃实验结果表明,Al/CFRP混合方管具有优异的耐撞性能;优化结果表明,可靠性优化解的约束可靠度相比于确定性优化解提高了10.96%,大大降低了失效概率,具有更强的实用性。研究结果有望对Al/CFRP混合薄壁吸能构件的优化设计提供参考。     

某型号固体火箭发动机喷管型面设计与数值计算

根据某型号固体火箭发动机总体设计要求及限制条件,给出了喷管型面设计方法。采用计算流体动力学(CFD)方法,用单方程（Spalart-Allmaras）湍流模型,分析计算了不同入口压力下喷管内流场特性和壁面压力、温度分布等。根据流场计算结果求出了发动机瞬时推力,并与地面推力试验结果进行了对比。     

Redesigning the space shuttles solid rocket motor seals

Last month's launch of the space shuttle Endeavour, was marked by the kind of cold weather that caused the explosion of the Challenger 10 years ago. In preparation, technicians pumped hot air in to keep the craft warmed, and circulated heated nitrogen gas over the instruments that direct the booster rockets. Protective warming bands were also placed over the O-rings that seal the joints of the solid rocket boosters. Faulty O-rings, normally flexible and pliable, but frozen stiff by the cold weather, were identified as the reason for the Challenger explosion, which resulted in the loss of seven astronauts. The following article reports on the improvements that have been made to sealing the solid rocket motor field joints since the disaster.     

Study of a liquid insulation for the solid rocket motor

Formula of a liquid insulation for a solid rocket motor (SRM) was studied in this paper. By analyzing vulcanization mechanism and comparing mechanical and thermal properties of the rubber, composition of the insulation with liquid raw material was determined. Ignition tests of motors with liquid insulation were successful. Results indicated that the tensile strength, elongation at break, shear strength, specific heat and thermal conductivity of the liquid insulation were 6.25 MPa, 590%, 3.61 MPa, 3.4174 × 10³ J/(kg K) and 0.421 W/(m K) respectively. The success of various ground ignition tests and flight test proved that this new liquid insulation can fulfill requirements of the SRM.     

Fracture characteristics of a burst tested maraging steel rocket motor case

A 0.3 m diameter, 2 m long and 0.0015 m thick, 18 nickel 1800 MNm^–2 grade maraging steel motor case was designed, fabricated and burst tested to gain experience for using the steel as booster case material in satellite launch vehicles. The bursting occurred at 15.2 MPa for which the effective hoop stress worked out to be 1754 MNm^–2 almost equal to the ultimate tensile strength (1764 MNm^–2) of the material in the solution treated and aged condition. The failure analysis revealed that the material failed due to normal tensile overload fracture. The burst test data was used to arrive at fracture mechanics parameters like crack size, gross section area stress and the stress for leak before bursting.     

基于细观仿真建模的CFRP细观破坏

碳纤维增强树脂基复合材料(CFRP)在细观上呈现纤维、树脂及界面组成的混合态,其切削加工过程的实质为刀具作用下材料细观层面的破坏至切屑宏观形成的演化过程。为了揭示CFRP切削加工过程中材料的细观破坏,建立了CFRP切削的细观有限元模型。该模型在几何上包含了纤维、基体及界面等组成相,而不是使用传统的等效均质建模方法。各组成相不仅考虑了各自不同的材料本构,而且为了能够模拟材料破坏,还将各组成相材料的失效及演化准则考虑其中。该模型可从细观层面更真实地模拟不同纤维角度CFRP单向板切削过程中纤维/基体断裂、界面开裂及演化的过程。仿真结果表明:不同纤维角度下CFRP细观破坏不同,切削0℃FRP时以界面开裂和纤维弯断为主;切削45°/90℃FRP时主要是刀具侵入工件,纤维基体被压断;切削135℃FRP时则以纤维弯曲断裂为主,断裂面往往在加工面以下。通过实验显微在线观测手段验证了模拟结果的正确性。      

超声波法测试固体火箭发动机燃速

为测量固体火箭发动机燃烧过程中推进剂燃速变化情况,组建可用于固体发动机地面试验特殊环境的超声波测量平台,应用超声波连续脉冲反射法测量,获得发动机不同界面的超声回波波形数据。通过设置区域增益并观察分析实验数据,从复杂的回波数据中提取出推进剂的厚度变化量,通过计算得到不同时刻推进剂的燃速。回波图可以清晰反映出推进剂端面的燃烧退移过程,进而可获得推进剂的燃烧规律。利用超声波法实现固体火箭发动机地面试验条件下推进剂燃速测量,测得实时连续的发动机燃速,可为固体火箭发动机结构设计及装药设计提供重要参数。     

An experimental and numerical investigation on torsional strengthening of solid and box-section RC beams using CFRP laminates

The issue of maintenance and repair/upgrading of existing structures has become a major issue, particularly extending the service lifespan of bridges. Fibre reinforced polymer (FRP) has shown great promise as a state-of-the-art material in flexural and shear strengthening as external reinforcement. However, little attention has been paid to torsional strengthening in terms of both experimental and numerical research. This paper reports the experimental work in an overall investigation of torsional strengthening of solid and box-section reinforced concrete beams with externally-bonded CFRP. This was found to be a viable method of torsional strengthening. Numerical work was carried out using non-linear finite element (FE) modelling. Good agreement in terms of torque–twist behaviour, steel and CFRP reinforcement responses, and crack patterns was achieved. The unique failure modes of all the specimens were modelled correctly as well.     

Viscoelastic response of solid rocket motor components for service life assessment

A methodology for determining the response of rocket motor materials and bondlines to thermal loadings by measuring their dynamic mechanical properties is reported. The critical temperatures at which debonding and/or propellant cracking occur and the number of thermal cycles required to induce failure were evaluated. These results were compared with those from instrumented rocket motors subjected to similar thermal loadings. A model, developed for fibre reinforced composites, was applied to the propellant-inhibitor bimaterial obtained from a rocket motor. The internal energy dissipation due to a lack of perfect adhesion at the propellant–inhibitor interface, tan δ_adh, was used to give an indication of the failure mode of the bondline (i.e., adhesive failure at the interface or cohesive failure in the propellant) and the bond adhesion parameter, C, was related to the bond strength measured by rectangular bond-in-tension tests. This revised version was published online in November 2006 with corrections to the Cover Date.