Study on the coupling calculation method for the launch dynamics of a self-propelled artillery multibody system considering engraving process

The launch dynamics theory for multibody systems emerges as an innovative and efficacious approach for the study of launch dynamics,capable of addressing the challenges of complex modeling,diminished computational efficiency,and imprecise analyses of system dynamic responses found in the dynamics research of intricate multi-rigid-flexible body systems,such as self-propelled artillery.This advancement aims to enhance the firing accuracy and launch safety of self-propelled artillery.Recognizing the shortfall of overlooking the band engraving process in existing theories,this study introduces a novel coupling calculation methodology for the launch dynamics of a self-propelled artillery multibody system.This method leverages the ABAQUS subroutine interface VUAMP to compute the dynamic response of the projectile and barrel during the launch process of large-caliber self-propelled artillery.Additionally,it examines the changes in projectile resistance and band deformation in relation to projectile motion throughout the band engraving process.Comparative analysis of the computational outcomes with experimental data evidences that the proposed method offers a more precise depiction of the launch process of self-propelled artillery,thereby enhancing the accuracy of launch dynamics calculations for self-propelled artillery.

Application of Choquet Integral-Importance-Performance Analysis and TOPSIS Methods in Approaching the Preference Factors of Calligraphy and Seal Engraving Imagery

Classical Chinese characters,presented through calligraphy,seal engraving,or painting,can exhibit different aesthetics and essences of Chinese characters,making them the most important asset of the Chinese people.Calligraphy and seal engraving,as two closely related systems in traditional Chinese art,have developed through the ages.Due to changes in lifestyle and advancements in modern technology,their original functions of daily writing and verification have gradually diminished.Instead,they have increasingly played a significant role in commercial art.This study utilizes the Evaluation Grid Method(EGM)and the Analytic Hierarchy Process(AHP)to research the key preference factors in the application of calligraphy and seal engraving imagery.Different from the traditional 5-point equal interval semantic questionnaire,this study employs a non-equal interval semantic questionnaire with a golden ratio scale,distinguishing the importance ratio of adjacent semantic meanings and highlighting the weighted emphasis on visual aesthetics.Additionally,the study uses Importance-Performance Analysis(IPA)and Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)to obtain the key preference sequence of calligraphy and seal engraving culture.Plus,the Choquet integral comprehensive evaluation is used as a reference for IPA comparison.It is hoped that this study can provide cultural imagery references and research methods,injecting further creativity into industrial design.

DXF File Identification with C# for CNC Engraving Machine System

This paper researches the main technology of open CNC engraving machine, the DXF identification technology. Agraphic information extraction method is proposed. By this method, the graphic information in DXF file can be identified and transformed into bottom motion controller’s code. So the engraving machine can achieve trajectory tracking. Then the open CNC engraving machine system is developed with C#. At last, the method is validated on a three axes motion experiment platform. The result shows that this method can efficiently identify the graphic information including line, circle, arc etc. in DXF file and the CNC engraving machine can be controlled well.

Dynamic analysis of a guided projectile during engraving process

The reliability of the electronic components inside a guided projectile is highly affected by the launch dynamics of guided projectile.The engraving process plays a crucial role on determining the ballistic performance and projectile stability.This paper analyzes the dynamic response of a guided projectile during the engraving process.By considering the projectile center of gravity moving during the engraving process,a dynamics model is established with the coupling of interior ballistic equations.The results detail the stress situation of a guided projectile band during its engraving process.Meanwhile,the axial dynamic response of projectile in the several milliseconds following the engraving process is also researched.To further explore how the different performance of the engraving band can affect the dynamics of guided projectile,this paper focuses on these two aspects:(a) the effects caused by the different band geometry;and(b) the effects caused by different band materials.The time domain and frequency domain responses show that the dynamics of the projectile are quite sensitive to the engraving band width.A material with a small modulus of elasticity is more stable than one with a high modulus of elasticity.

Rock Engravings and Paintings: Rethinking of the Cupules, Gongs, and Grinding Hollows of Siuyu and Ughaugha in Singida East (Tanzania)

Our recent archaeological expeditions in the Siuyu and Ughaugha wards of Singida eastern province have recuperated the very compelling rock engravings (petroglyphs) that weren’t reported in Tanzania before. Archaeologically, Singida’s fame emanated from her endowments of rock paintings. However;during this research, we did discover rock cupules, gongs, and grinding hollows art together with rock paintings (pictographs) that have opened up a new avenue for rock art studies in Tanzania. We carried out intensive site surveys around four sites namely Siuyu, Ngaghe, Misimbwa and Ughaugha B with the aims of solely examining, recording, and documenting archaeological artifacts on the surface in order to research the cultural and behavioural patterns of early humans in the Singida region. Surveys also enabled us to locate suitable areas where future excavations would be established. In some cases, ethnographic enquiries were employed to get supplementary information on the present-day use of rock art sites. Besides, we interviewed local people to assess their general understanding of the presence of more sites or helping in locating, and discovering new sites. Through ethnographic inquiries, we discovered several sites with substantial number of rock engravings that were never document by any researcher. On top of that, this study reports other archaeological potentials of the region by describing in detail their significances for future research undertakings. Additionally, this paper article reports on the occurrence of Middle Stone Age (MSA) archaeological assemblages from the open-air site and the presence of grinding hollows and rock cupules (Siuyu complexes) in central Tanzania for the first time.

Art of Chinese Seal Engraving Inscribed on the Representative List of the Intangible Cultural Heritage of Humanity in 2009

The art of seal en graving is a comerstone of Chinese fine arts. The seal was originally used as a signature or sign of authority, but it came to be used by all social classes and in much of Asia. The Seal *Engravers Society of Xiling in east China's Zhejiang Province, which was founded a century ago, preserves the art of seal engraving along with approximately 100 other specialized institutions. The design is first sketched on paper, and then engraved on stone, in reverse, with a knife.

基于MCGS组态软件的板材雕刻机控制系统设计

板材雕刻机是一种用于在板材上进行雕刻、切割、剪裁的机器。为提高雕刻机的速度和精度,并研究其在控制方面的应用,通常采用PLC控制伺服电机带动刀头进行精确的雕刻操作。板材雕刻机可以根据预先设计好的图案或模型进行雕刻,广泛应用于家具制造、建筑装饰、艺术品制作等领域。在板材雕刻机的控制系统中,通过MCGS组态软件,可以直观地反映雕刻过程,并精确地控制雕刻机进行预设图案的雕刻。通过优化控制、调整运动路径和采用高精度的传感器和编码器,可以大大提高雕刻机的速度和精度,实现更精细的雕刻效果。控制系统还能实时监测刀头位置和状态,及时调整雕刻参数,保证雕刻结果的准确性。

身管内膛磨损对弹丸运动规律的影响研究

火炮发射过程中,高速运动的弹丸会对身管内膛产生磨损,从而导致身管内膛的结构发生改变,直接影响到弹丸的运动特性。针对火炮身管内膛磨损所导致的弹丸运动规律变化的问题,以某大口径火炮为对象,通过建立5种不同内膛损伤程度的身管有限元模型,利用ABAQUS/Explicit有限元软件及其VUAMP子程序,将内弹道方程组与有限元模型进行耦合求解。研究结果表明:随着径向磨损量的增加,弹丸的挤进过程加速,弹丸挤进过程的行程和时间变长,弹丸挤进结束时的速度变大,主要弹道性能如初速和膛压逐渐减小。此研究为深入了解内膛损伤对弹道性能变化规律的影响提供了有益参考,为提高火炮性能及延长其使用寿命提供了有力支持。

论江苏古代杜集刊刻的文化特征

从宋代至清代,江苏刻书家紧密结合杜诗学的发展特征,刊刻了多种杜集,无论数量还是质量皆领全国之先,创造了多个杜集版本史上的“第一”。江苏古代杜集刊刻体现出博大的人文情怀,奠定了江苏古代杜诗学研究重镇的学术地位。

现代火炮内弹道面临的问题与对策

从现代火炮及弹药技术的发展趋势,分析了火炮内弹道面临的问题,阐述了火炮内弹道理论与技术的发展方向,集中体现在三个方面,一是提高常规固体发射药火炮的作战效能;二是发展与制导弹药等特种弹药发射方式相适应的内弹道理论与控制技术;三是研究新能源火炮的内弹道理论与控制技术。在此基础上,结合国内外研究状况,对若干重点问题进行了述评,并提出了研究对策。

基于线激光的化铣激光刻型在机精度检测方法

化铣激光刻型工艺是飞机蒙皮加工的重要方式,目前尚缺乏在机测量方法来检测激光刻型的精度与质量。针对此问题,提出了基于线激光的化铣激光刻型在机精度检测方法。首先,基于齐次坐标变换建立了五轴激光刻型机和线激光传感器的运动学模型,确定激光测量坐标系与工件坐标系之间的变换关系,据此获得刻型线扫描点云。然后,基于模板匹配提取单帧刻型槽截面轮廓特征,并通过Levenberg-Marquardt算法求解刻型线槽宽、槽深以及位置信息。再通过点云分割、轮廓匹配和轮廓误差计算方法得到激光刻型的轮廓误差。最后,通过激光刻型在机精度检测试验验证所提出方法的有效性,试验结果表明,该方法能够有效评估刻型线的均匀性和轮廓精度,为加工误差溯源、工艺改进和提高刻型线的轮廓精度提供了重要参考依据。

空间目标远距离磁控方法及应用分析

星间电磁力/力矩作用相对于传统航天器操控方式,具有不消耗推进剂、无羽流污染、可控能力强等优势。因此,在交会对接、编队集群、失效卫星消旋等方面得到了广泛关注。然而,电磁力/力矩的数值与场源作用距离的3到4次方成反比,导致电磁力/力矩的有效作用空间有限。磁化同轴枪强流脉冲放电装置可产生高传输速度(~1000 km/s)、高电子密度(~10^(16)cm^(-3))、高能量密度(~1 MJ/m^(2))、具有球马克位形的等离子体环,且等离子体环的放电电流可产生强度可观的环向磁场和极向磁场(~1 T)。此外,等离子体环的生成和输运环境与空间真空环境高度契合。基于磁化同轴枪生成具有球马克位形的等离子体环并将等离子体环所携带磁场远距投送的新型磁控方式,本文研究可控等离子体环远距投送对空间目标的磁控能力以及对空间目标消旋/回收的应用潜力等,并通过初步仿真算例予以验证结论的正确性。

基于激光雕刻的个性化鼻贴设计及应用效果评价

目的探讨激光雕刻的个性化鼻贴应用于鼻导管留置患者的效果。方法选取2022年2月至2023年2月于兰州大学第一医院行食管癌手术需经鼻留置管道的124例患者为研究对象,按照随机数字表法将其分为试验组和对照组,每组各62例。对照组患者采用常规裁剪的鼻贴固定鼻导管,试验组患者采用激光雕刻的个性化鼻贴。观察两组固定装置下的导管移位或滑脱、鼻贴卷边及更换次数、鼻部医疗器械相关压力性损伤、医用粘胶相关皮肤损伤及患者舒适度。结果试验组患者的导管移位率、鼻贴卷边次数及更换次数均显著低于对照组(P<0.05);试验组患者的鼻腔黏膜压痕、鼻腔疼痛、鼻部压力性损伤及医用粘胶相关性皮损发生率均显著低于对照组(P<0.05);试验组患者的生理维度舒适度显著优于对照组(P<0.05)。结论激光雕刻的个性化鼻贴可降低临床鼻导管移位、鼻贴卷边及更换次数,减少鼻部医疗器械相关压力性损伤及医用粘胶相关皮肤损伤的发生,提高患者的舒适度。

某大口径火炮不同坡膛锥角弹丸挤进过程

为对某大口径火炮不同坡膛锥角时弹丸挤进过程进行对比分析,通过光滑粒子流体动力学法仿真某装药条件下弹带挤进过程。仿真得到挤进阻力和导转力矩,分析产生力矩波动的原因,并提出减轻力矩波动、缓解膛线受力的改进措施。结果表明,该研究能为坡膛锥角对弹带刻槽影响的研究提供参考。

尼龙-紫铜复合弹带结构设计及动态挤进特性分析

针对大口径火炮在弹带挤进阶段由于应力过大易对炮膛内壁造成损伤的问题,以大口径火炮发射过程的内弹道特性为背景,展开尼龙-紫铜复合弹带的结构设计及其动态挤进过程的数值仿真研究。基于现有紫铜材质弹带,通过注塑工艺制备一种尼龙-紫铜复合结构弹带,降低挤进过程中的弹带应力。利用经典内弹道方程组求解内弹道过程中弹丸弹底压力变化,并作为动力条件展开动力学分析,使用单一及复合材质弹带的弹丸挤进过程中的内弹道动力学参数,分析尼龙厚度对复合弹带性能的影响。研究发现,相比于紫铜弹带弹丸,相同条件下使用尼龙弹带的弹丸内弹道动力学参数更高,而挤进终点时刻弹带应力更低;对于使用复合结构弹带的弹丸而言,其内弹道性能和弹带尼龙含量相关。复合弹带尼龙厚度越厚,则挤进过程中弹丸内弹道动力学参数越高,而挤进终点时刻弹带应力越低。相关研究可为中大口径火炮弹带设计提供一定参考。

发射不同被甲材料弹头各向异性身管膛内应力状态

为研究某小口径步枪发射过程中身管膛内的应力场与温度场,建立弹头膛内运动时期弹头/身管相互作用的精细热力耦合有限元模型,其中考虑了温度对身管与被甲材料力学性能的影响以及枪管钢力学性能的各向异性。仿真获得覆铜钢被甲弹头和铜被甲弹头挤进运动规律与身管膛内应力状态变化。研究结果表明:被甲材料的不同对挤进过程有很大影响,钢被甲弹头挤进阻力大于铜被甲,相应地前者膛内应力也大于后者;身管不同轴向位置处应力分布规律不同,坡膛处内膛应力最大值在阳线导转侧,膛口处内膛应力最大值在阴线上。研究结果为优化弹头/枪管匹配提供了支持。

某小口径火炮弹丸挤进过程动力学特性分析

为研究某小口径火炮不同坡膛结构下弹丸挤进过程的动力学特性,建立了考虑挤进阻力变化的内弹道方程组并通过vuamp子程序引入到有限元求解中,实现了挤进过程中内弹道计算与弹丸挤进有限元仿真耦合求解。通过对弹丸全膛运动的仿真分析验证了模型的可行性,随后得到并分析不同坡膛锥度、膛线深度及阴线宽度下挤进过程中弹丸的速度、加速度、挤进阻力和膛压曲线及变化影响规律。结果表明,坡膛锥度对挤进过程中弹丸的动力学参数影响不是单调的,而膛线深度及阴线宽度的改变则单调地影响弹丸动力学参数,对优化坡膛结构及弹带设计具有一定的指导意义。

明代江南家族刻书、藏书对画学论著的保存与传播——以毛晋汲古阁为例

检索现存画论古籍资料,明代以前诸书均赖明刊本以保存,而此中贡献最大的即为江南地区文化大族的私人刻书。他们不仅刊刻古书,也刊刻了许多明代的画论著作,许多绘画思想得以借此传播。明代江南藏书家众多,其中毛晋汲古阁作为明代江南文人刻书与藏书的代表,对画学论著的收录、保存与传播起到积极推动作用。

基于改进YOLOv5s的木刻雕版元素检测方法研究

针对传统目标检测算法在处理具有复杂纹理木刻雕版图像时存在漏检、参数量大、检测和推理速度慢等问题,通过改进YOLOv5s模型,提出一种轻量化目标检测算法。首先,采用FasterNet作为特征提取模块,解决原始YOLOv5s参数量大、运行时间长以及算法要求高等问题;其次,在特征提取网络后添加坐标注意力机制以提高模型对木刻雕版元素特征的提取能力;最后,引入轻量化上采样CARAFE,减少上采样过程中特征信息的损失并提升模型的检测精度。为了验证方法的有效性,文中在自己收集的数据上进行测试,与初始YOLOv5s模型相比,改进后的模型平均精度提升了2.2%,检测速度提升了46.53%。实验结果表明,改进后的模型可以快速定位和识别木刻雕版元素,实现对初始模型的轻量化,可以有效部署于嵌入式设备和移动设备。