基于ABAQUS的身管外自紧仿真分析

自紧身管是高膛压火炮普遍采用的身管，目前均采用内自紧方式进行加工。为检验外自紧方式加工自紧身管的可行性，采用ABAQUS软件对身管内外自紧加工的应力分布进行了仿真分析。研究表明：内外自紧都会导致身管内壁先于外壁塑性变形并达到一定的自紧度；内自紧可减小射击应力，外自紧会使射击应力增大；对于理想弹塑性材料，内自紧身管射击应力小于材料屈服极限，外自紧身管射击应力的塑变区域不超过制造时塑变区域，内外自紧方式均可以提高身管强度；达到同样的自紧度时，内外自紧身管具有同样的强度，但是外自紧需要的压力要小于内自紧压力。     

不同土体对迫击炮射击稳定性影响的动力学分析

建立迫击炮后坐过程的仿真模型,并进行动力学仿真,利用数值计算结果确定不同类型土壤情况下射击对迫击炮稳定性的影响。     

某迫击炮身管结构优化分析

考虑采用新型工艺后材料最大弹性极限,研究了某迫击炮身管壁厚减薄的结构优化方法。首先,采用有限元方法进行静态分析,通过三维软件 UG建立了身管实体模型。对身管结构进行合理简化后,导入到 ANSYS中进行膛压分析计算,得到了身管不同位置管壁所受应力随壁厚减薄的变化曲线。综合分析各种壁厚减薄方案,得到了身管承载性能最优的方案,并采用流固耦合动态响应加以验证。结果表明,静态分析结果较动态分析结果更接近真实受力状况。最终,迫击炮身管结构重量经仿真优化后可减轻13%,因而,该身管轻量化方法有效而可靠。     

某迫击炮身管结构优化分析（英文）

考虑采用新型工艺后材料最大弹性极限,研究了某迫击炮身管壁厚减薄的结构优化方法。首先,采用有限元方法进行静态分析,通过三维软件UG建立了身管实体模型。对身管结构进行合理简化后,导入到ANSYS中进行膛压分析计算,得到了身管不同位置管壁所受应力随壁厚减薄的变化曲线。综合分析各种壁厚减薄方案,得到了身管承载性能最优的方案,并采用流固耦合动态响应加以验证。结果表明,静态分析结果较动态分析结果更接近真实受力状况。最终,迫击炮身管结构重量经仿真优化后可减轻13%,因而,该身管轻量化方法有效而可靠。     

基于AWE的迫击炮身管散热分析与优化

在ANSYS Workbench环境下对迫击炮身管参数化建模,利用ANSYS Workbench平台的DesignXplorer模块所提供的DOE技术,分析了迫击炮身管散热结构参数与散热量、总重量之间的关系,在此基础上选出最优结构参数.最终结果表明该优化方法可提高散热量,并降低身管总重量.     

考虑身管壁压的迫击炮炮身强度分析

考虑迫击炮在发射过程中膛底和身管内壁压力不断变化的特点,对迫击炮身管和炮尾进行有限元分析。由于身管和炮尾是轴对称结构,故将其简化成二维轴对称平面模型;并根据迫击炮弹在膛内运动的不同时刻,在膛底施加变化的膛压,同时把身管内表面分成22段,分别施加膛压。由此来分析身管和炮尾的强度并给出相应的解决办法。     

身管疲劳损伤与可靠寿命分析

身管是身管类武器的重要组成部分,在武器循环射击的过程中,身管极易产生疲劳失效,导致武器寿命告终。为预测身管疲劳寿命,提出了一种基于疲劳损伤变化规律的疲劳寿命分析方法:首先通过有限元仿真,研究了温度和膛压载荷综合作用下的身管内壁应力的变化。然后综合考虑各因素的随机性,基于蒙特卡洛原理,应用局部应力应变法,建立了疲劳损伤的评估模型。基于退化数据分析的方法,建立了疲劳损伤随射弹量的变化规律,并通过退化模型预测了身管的可靠寿命。     

基于AWE某迫击炮座钣瞬态动力学分析

为了优化迫击炮座钣的结构设计,采用有限单元法对某型迫击炮座钣三维模型进行瞬态动力学分析,得到了整个座钣的结构应力和变形分布规律以及座钣关键部位的动应力变化曲线,为迫击炮座钣结构的进一步优化提供了参考。     

基于有限元法的炮身瞬态动力学分析

为验证炮身设计的合理性，在Workbench中建立了某小口径火炮炮身的有限元模型，设置了边界条件，分步加载载荷，通过仿真计算得到了射击过程中身管内部应力分布及相应的应力值，验证了炮身强度满足设计要求，为火炮的设计和进一步的结构优化提供了理论参考依据。     

不同强度理论下自紧身管强度数值仿真

为考察不同强度理论下自紧身管强度的差异,对基于第三强度理论、第四强度理论开端、第四强度理论闭端自紧身管加工时、加工后和射击时身管截面应力分布进行了数值仿真,并计算了不同强度理论下某型火炮局部自紧身管的强度。研究标明:不同强度理论下自紧身管截面上应力分布曲线相似;在自紧度相同情况下,基于第三强度理论、第四强度理论开端、第四强度理论闭端的自紧身管强度依次变大。     

某榴弹发射器枪管瞬态热结构耦合分析

为了提高自动武器的使用性能,寻求降低膛壁温度的方法,简介了传热机理,并运用ANSYS软件建立了枪管二维轴对称有限元模型,确定枪管的边界条件,得到了单发时枪管的温度分布和连发时的温度及应力分布,并对枪管的温度场和应力进行了研究。然后对枪管在温度场、耦合场及膛压作用下的应力进行了比较。研究结果对枪管设计有一定的参考价值。     

大口径火炮多发连射炮管热力耦合分析

通过建立一维内弹道学两相流模型和经典圆管瞬态热传导模型,研究了大口径火炮多发连射过程的瞬态传热特性,并用ABAQUS软件进一步分析20发连射时炮管的热结构耦合场。得到某155mm火炮药室部温度场和瞬态热应力场分布规律,为进一步评测炮管的疲劳裂纹和确定剩余寿命提供了参考。     

Ultrasonic Velocity as a Tool for Physical and Mechanical Parameters Prediction within Geo-Materials: Application on Cement Mortar

This paper discusses the ability of ultrasonic wave velocity to evaluate some physical parameters within mortar. The behavior of ultrasonic pulse velocity within mortar subjected to incremetal stress was also studied. For experimentation, we carried out ultrasonic measurements on mortar samples before and during uniaxial compressive strength, perpendicularly to the stress direction. The water/cement ratios were varied in order to contribute certain specific characteristics. A set of expressions was obtained linking the initial velocities of longitudinal ultrasonic waves with compressive strength, density, porosity and load at elastic limit.The evolution of ultrasonic velocity through mortar samples under continuous incremental uniaxial stress were also investigated. The results illustrated the behavior of ultrasonic pulse velocity as a function of the applied stress. It was observed that velocity did not decrease under initial loading and until about 70% of the ultimate stress, where sudden decrease occurred, followed by the failure of the material.     

一种新型金属材料微细槽孔结构电加工方法

在枪管、飞机叶片、弹体壳腔等的微细裂纹无损检测试验研究中,需要先在这些场合预制微细人工伤。为解决这类微细人工伤的单件或者小批量加工问题,需要研究一种加工环境质量要求相对较低、热效应及残余应力相对较小的新型加工方法。本文提出一种应对加工需求的新方法,即以普通的电火花加工原理为基本雏形,利用微细脉冲产生的电弧放电热,逐步将金属微量熔蚀,在加工间隙中,使油液及时将切屑冲走,以实现顺利加工。通过样机开发与实际加工效果分析可知,工件切口面满足要求,样机工作可靠,实现了小型化与便携功能,能够解决微细有槽孔结构的单件或者小批量快速加工问题,为金属材料的微裂纹蚀刻设备的微型化与无损检测技术奠定了基础。     

某超高射速武器身管设计方法

超高射速武器是一种新概念武器,其显著特点是射速高。身管是其关键部件,直接制约着武器效能的发挥。为了设计合理可用的身管,首先使用matlab软件进行数值模拟,得出了在给定条件下身管的受力情况。再对各种强度理论进行分析,在此基础上,采用平均压力法来设计身管。给出了某超高射速武器身管结构尺寸的设计结果。该技术研究可为超高射速武器结构设计提供一定理论参考。     

Phenomenon of Barrelling in Square Billets of Aluminium During Cold Upset Forging

Experiments were carried out to generate data on the upset forging of square billets of annealed aluminium. The measured curvatures of the barrelled aluminium square billets were found to conform with calculated values using experimental data. The calculations were made on the assumption that the curvature of the barrel followed the geometry of a circular arc. It was further found that the measured radius of curvature of the barrel exhibited a straight-line relationship with the new geometrical shape factor irrespective of the aspect ratios of the square billets. Further empirical relationships were found to exist between the measured radius of curvature of the barrel and independently with other variables like hydrostatic stress and stress ratio parameter.     

Investigation of Damage Processes of Mortar in Different Aggregate Size by Acoustic Emission Characteristics

In order to study acoustic emission (AE) characteristics of damage process of mortar in different aggregate size, mortar specimens were tested under axial compression in the experiment, the whole damage evolution processes were monitored by full-digital AE acquisition system. The effects of mortar in different aggregate size on damage processes and failure mode were conducted by cumulative AE energy, amplitude, peak frequency and the ratio N/E (hits/energy) respectively. The ratio of cumulative AE hits of each frequency band and amplitude band to the whole cumulative AE hits in different stress level were counted, and the difference and evolution process of microcracks of mortar in different aggregate size in the failure process were revealed. The results show that cumulative AE energy increase with the increase of aggregate size in mortar. Distribution of cumulative AE hits of each amplitude band versus the stress in different aggregate size are the same, and AE hits of each amplitude band increase sharply suggests that the specimen will be destroyed. Besides, AE hits focus on low-frequency band at low stress level, while all peak frequency bands are active at high stress level, and the aggregate size of mortar have significant influence on cumulative hits of each peak frequency band. The ratio N/E decreased with the increase of aggregate size, and which increased linearly with the increase of the stress.