Missile guidance law design based on free-time convergent error dynamics

To solve the finite-time error-tracking problem in mis-sile guidance,this paper presents a unified design approach through error dynamics and free-time convergence theory.The proposed approach is initiated by establishing a desired model for free-time convergent error dynamics,characterized by its independence from initial conditions and guidance parameters,and adjustable convergence time.This foundation facilitates the derivation of specific guidance laws that integrate constraints such as leading angle,impact angle,and impact time.The theoretical framework of this study elucidates the nuances and synergies between the proposed guidance laws and existing methodologies.Empirical evaluations through simulation comparisons underscore the enhanced accuracy and adaptability of the proposed laws.

Dynamic-based model for calculating the boulder impact force in debris flow

The boulder impact force in debris flow is generally calculated by static methods such as the cantilever beam models.However,these methods cannot describe the dynamic scenario of boulder collision on structures,so the inertia and damping effects of the structures are not involved causing an overestimation on the boulder impact force.In order to address this issue,a dynamic-based model for calculating the boulder impact force of a debris flow was proposed in this study,and the dynamic characteristics of a cantilever beam with multiple degrees of freedom under boulder collision were investigated.By using the drop-weight method to simulate boulders within debris flow,seven experiments of drop-weight impacting the cantilever beam were used to calibrate the error of the dynamicbased model.Results indicate that the dynamic-based model is able to reconstruct the impact force history on the cantilever beam during impact time and the error of dynamic-based model is 15.3%in calculating boulder impact force,significantly outperforming the cantilever beam model’s error of 285%.Therefore,the dynamic-based model can overcome the drawbacks of the static-based models and provide a more reliable theoretical foundation for the engineering design of debris flow control structures.

Experimental study of solid-liquid origami composite structures with improved impact resistance

In this paper,a liquid-solid origami composite design is proposed for the improvement of impact resistance.Employing this design strategy,Kresling origami composite structures with different fillings were designed and fabricated,namely air,water,and shear thickening fluid(STF).Quasi-static compression and drop-weight impact experiments were carried out to compare and reveal the static and dynamic mechanical behavior of these structures.The results from drop-weight impact experiments demonstrated that the solid-liquid Kresling origami composite structures exhibited superior yield strength and reduced peak force when compared to their empty counterparts.Notably,the Kresling origami structures filled with STF exhibited significantly heightened yield strength and reduced peak force.For example,at an impact velocity of 3 m/s,the yield strength of single-layer STF-filled Kresling origami structures increased by 772.7%and the peak force decreased by 68.6%.This liquid-solid origami composite design holds the potential to advance the application of origami structures in critical areas such as aerospace,intelligent protection and other important fields.The demonstrated improvements in impact resistance underscore the practical viability of this approach in enhancing structural performance for a range of applications.

Grey-theory based algorithm for impact assessment of green design

Life cycle assessment (LCA) is an important content of green design;the major phase of LCA is impact assessment. After classifying the impact factors, with grey-system theory, the evaluating grey-groups and their whitening weighing functions are defined;the grey-cluster analysis of each classified impact is performed;based on analyzing results, the calculating method of classified impact index is given. By range of action, the impact classes are grouped to three groups - global impact, regional impact, and local impact;the calculating methods of grouped and overall impact index are presented. Finally, an application example of comparative choice of a category of products - three materials, steel, aluminum and engineering plastics is given.

Reliability Design for Impact Vibration of Hydraulic Pressure Pipeline Systems

The research of reliability design for impact vibration of hydraulic pressure pipeline systems is still in the primary stage,and the research of quantitative reliability of hydraulic components and system is still incomplete.On the condition of having obtained the numerical characteristics of basic random parameters,several techniques and methods including the probability statistical theory,hydraulic technique and stochastic perturbation method are employed to carry out the reliability design for impact vibration of the hydraulic pressure system.Considering the instantaneous pressure pulse of hydraulic impact in pipeline,the reliability analysis model of hydraulic pipeline system is established,and the reliability-based optimization design method is presented.The proposed method can reflect the inherent reliability of hydraulic pipe system exactly,and the desired result is obtained.The reliability design of hydraulic pipeline system is achieved by computer programs and the reliability design information of hydraulic pipeline system is obtained.This research proposes a reliability design method,which can solve the problem of the reliability-based optimization design for the hydraulic pressure system with impact vibration practically and effectively,and enhance the quantitative research on the reliability design of hydraulic pipeline system.The proposed method has generality for the reliability optimization design of hydraulic pipeline system.

Optimal design and dynamic impact tests of removable bollards

Anti-ram bollard systems, which are installed around buildings and infrastructure, can prevent unauthorized vehicles from entering, maintain distance from vehicle-borne improvised explosive devices （VBIED） and reduce the corresponding damage. Compared with a fixed bollard system, a removable bollard system provides more flexibility as it can be removed when needed. This paper first proposes a new type of K4-rated removable anti-ram bollard system. To simulate the collision of a vehicle hitting the bollard system, a finite element model was then built and verified through comparison of numerical simulation results and existing experimental results. Based on the orthogonal design method, the factors influencing the safety and economy of this proposed system were examined and sorted according to their importance. An optimal design scheme was then produced. Finally, to validate the effectiveness of the proposed design scheme, four dynamic impact tests, including two front impact tests and two side impact tests, have been conducted according to BSI Specifications. The residual rotation angles of the specimen are smaller than 30~ and satisfy the requirements of the BSI Specification.

Dynamic impact protective body armour:A comprehensive appraisal on panel engineering design and its prospective materials

Personal body armour is one of the most important pieces of equipment to protect human beings from various critical and fatal injuries.In today’s modern world,various organizations including law enforcement and security service have made it mandatory for their personnel to wear personal protection system while on field duty.However,the systems should comprise an improved ballistic performance,light-weighted,flexible as well as comfortable panel not only to be accepted with a wider range but also for effective performances of the consumer.Generally,the overall performances of the protective body armour could be affected by various parameters including armour design techniques,type of materials used and finishing of the panels.The current paper aims to critically review state-of-art for armour panel design techniques and the different perspective body armour materials.The paper starts by discussing the different body armour and its category.Later,the different states of technology for armour panel design(mostly for women),its problems and the possible solutions will be cited.Later,the commonly used different polymeric fibrous and the future possible advanced materials including carbon nanotube(CNT),Graphene CNT and shear thickening fluids(STFs)treated materials for developing the reinforced body armour panel will be discussed.The authors believe that this paper will enlighten useful guidelines and procedures about the different panel design techniques and current and promising future materials for researchers,designers,engineers and manufacturers working on the impact resistance body armour field.

Landscape Design of Colleges and Universities Based on Low Impact Concept: A Case Study of the Shared Training Base from Jiangsu Vocational Institute of Architectural Technology

In recent years, the acceleration of urbanization process results in frequent watedoggingj the decline of groundwater level and frequent urban infiasttucture construction pfoblem. In order to better safeguard complex ecological system and ecological civilization construction in tiie city, and solve the appropriate ratio of water and wetland area to total land area, for water ecological civilization construction in low impact development, the pursuit of water resources sustainability, the pursuit of safety concept, the pursuit of ecological engineeting technology and the pursuit of art are proposed. Based on these pursuits, the principles and design methods of campus landscape creation in colleges and univefsities under the concept of elow impact^ is analyzed. Taking the landscape design, of the shated training base from Jiangsu Vocational Institute of Architectural Technology as an example, how to use the concept of clow impacf？ development in actual cases is analyze4 to achieve rainwater collection, water purification, water storage and rainwater ecological utilization, and create a holistic, ecological and diverse sustainable landscape in colleges and universities.

Impact of Risk on Performance of Design and Build Projects in Lagos State, Nigeria

＂Design and Build＂ procurement method has been in use in Nigeria and this method has been latent with a lot of risks. This study intends to identify the risk inherent in ＂Design and Build＂ and also to evaluate the impact of the identified risks on project performance. A descriptive research survey is undertaken for this study. Snowballing sampling technique was used via the use of questionnaires. Population of the study includes contracting organizations, consultants and clients＇ organizations that are recently involved in ＂Design and Build＂ projects. A total of 39 questionnaires were distributed and 27 were returned and used for the analysis. Statistical Package for Social Sciences was used for analyzing the data collected. Descriptive statistical tool of mean item score was employed for the analysis. The results show that the most prominent risk is change in quantity/scope of work in terms of cost related risk while in terms of time related risks the most prominent risk is design changes. Errors and omissions during construction are the risks prominent in terms of quality. In conclusion, ＂Design and Build＂ procurement has a lot of inherent, unresolved and undefined cost, time and quality related factors that can trigger off risks that will affect performance of DB project. Implications of this study to practitioners in the construction is such that the findings of this study can create awareness for stakeholders and construction practitioners of the prominent risks that affect DB projects and this can help in better management of future DB projects in Nigeria and other developing countries. Design and Build procurement in spite of these plethora of risks is still strongly recommended for clients, stakeholders and other practitioners in the construction industry for use in their future projects. This procurement method delivers project faster, within cost and offers good quality of workmanship and product to users of this method.

A study on landscape design paradigm from the perspective of visual impact and experience

Space is one of the important landscape node types in landscape architecture, and it is the supporting framework of landscape architecture. The understanding of space and space art landscape design in the garden by the way of consulting and reference case, in order to better the performance of landscape art in the landscape garden for the purpose of systematic analysis of knowledge structure of landscape space, provide a comprehensive reference for the future design of the landscape garden. This paper from the background of our landscape design conception, combined with the trend of landscape design Chinese traditional garden design techniques and modem residential area of research and analysis, explore the new design of modem residential area, in order to create a Chinese characteristics, local characteristics of the residential landscape, to further explore the charm of traditional culture, highlighting the regional characteristics.

某燃料运输容器在不同冲击条件下的动态力学响应特征

目的识别国标规范要求的典型冲击场景下某燃料运输容器动态力学响应特性,为运输容器的安全设计及防护措施等提供参考。方法使用有限元方法对某燃料运输容器进行多种典型冲击场景的数值模拟分析,结合试验结果验证模拟方法的正确性和实用性。以典型工况为例,识别燃料运输容器的冲击响应特征,并判别最严酷冲击工况。进一步讨论反弹跌落多次碰撞、螺栓预紧力等多方面因素对响应特征的影响规律。结果通过与试验结果对比,验证了数值模拟方法的正确性。分析了典型冲击场景下燃料运输容器的响应特征,并推理了相应最严酷冲击姿态。有限元模拟结果显示缓冲结构起到了很好的防护作用。运输容器第一次撞击引起的冲击响应显著高于反弹后再次跌落撞击过程中的冲击响应;螺栓预紧力主要影响局部应力状态,对螺栓塑性变形和破坏的影响不明显。结论某燃料运输容器具有很好的缓冲性能,可以满足防护要求,不同冲击条件下的最严酷冲击工况互不相同。反弹跌落碰撞和螺栓预紧力对容器整体响应特征及最终变形或破坏形貌无显著影响。

某燃料运输容器在多过程序贯冲击条件下的动态力学响应特征

目的识别某燃料运输容器在国标规范要求的多过程序贯冲击条件下的冲击响应特性,为运输容器的安全设计及防护措施等提供参考。方法开展运输容器在1.2 m高度侧跌、钢棒1 m高度贯穿、500 kg重物9 m高度冲砸和1 m高度穿刺等4种事故场景顺序叠加作用条件下的多过程序贯冲击试验,同时开展相应的冲击损伤累积有限元模拟分析,研究运输容器结构在多种冲击载荷序贯叠加作用下的动态响应特征。结果模拟结果同试验结果符合较好,验证了冲击损伤累积有限元模拟方法的正确性和实用性。试验结果和数值模拟结果均显示在多过程序贯冲击条件下,容器缓冲结构起到很好的防护作用,可对燃料部件产生有效防护,且结构功能保持完好。结论燃料运输容器具有很好的缓冲性能,可以满足国标规定的多过程序贯冲击条件下的防护要求。冲击损伤累积有限元模拟方法可较准确地分析复杂结构在多过程序贯冲击条件下的动态响应特征,具有较好的实用性。

四足机器人单自由度腿部优化设计及仿真

基于仿生原理的四足机器人是当今国内外众多学者研究的热点。针对四足机器人运动平稳性的要求,提出了一种竖直方向改进型等速运动规律和前进方向仿生运动规律相结合的无冲击足端轨迹形式,推导出分段函数表达式;针对四足机器人存在的驱动多、腿部刚度弱的情况,构思了一种由两个曲柄摇杆机构、同步带传动和一对外啮合圆柱齿轮传动组成的单自由度的新型腿部机构,并建立该机构的运动学模型,推导了其足端的坐标;综合利用遗传算法和非线性优化一般方法,以无冲击的足端轨迹的逼近度为目标,优化计算了机构各构件的最佳运动尺寸和初始位置;使用三维建模软件搭建简化的虚拟样机模型,并导入到Adams软件中进行了Trot步态仿真试验,运动效果达到了预期设计。所提出的无冲击轨迹可以为其他足式机器人的足端轨迹规划提供参考,由两个曲柄摇杆机构组成的多连杆腿部机构优化设计方法为足式机器人腿部设计提供了基础和创新思路。

基于能量分配原理的煤矿机械冲击行为研究及装置设计

为研究煤矿机械服役过程中的冲击损伤行为,以球形冲击物水平冲击金属矩形板料为例,获取冲击过程能量分配关系,结合实际冲击环境,设计并搭建气动水平冲击实验系统,获取不同气压下板料的冲击行为。通过仿真和实验,对理论计算得出的变形量和加速度进行验证,并运用多项式拟合方式优化输出参数加速度。将计算、实验和仿真结果作对比,结果表明,冲击过程中冲击物动能主要被材料塑性变形、运动动能和碰撞损失耗散,当被冲击板料中心区域发生断裂时,板料塑性变形和碰撞损失的能量耗散会减小。优化后的冲击过程能量分配关系的理论、实验和仿真结果吻合较好,最大偏差不超过9.39%。

基于DDAM方法的天线罩冲击响应分析

结合某型号天线罩,采用ANSYS有限元分析软件,运用动力学设计分析方法(DDAM)对天线罩进行了纵向、横向和垂向的冲击响应分析,考察罩体结构在冲击载荷作用下的应力和位移响应。结果表明:天线罩在垂向冲击载荷作用下的位移和应力响应最大,其最大Mises应力为42.1 MPa,小于材料强度,其和位移最大值为40.356 mm,满足结构刚度要求,因此该天线罩在冲击载荷作用下结构安全可靠,能够满足正常工作需求。

涡轮起动机中斜撑离合器的瞬态冲击与楔合特性研究

将稳态楔合拓展至瞬态冲击是深入研究斜撑离合器正向设计的重要组成部分。本文从机械动力学理论出发,关联输入输出端载荷与响应特征,建立斜撑离合器冲击受载微分方程,揭示出离合器由瞬态楔合至稳态传动过程蕴含的动力学原理和一般规律。在此基础上,推导出斜撑离合器内外传动轴的综合应力分析模型,并提出运用接触应力、综合应力和楔角等指标整体考察离合器传动性能的校核方法。最后以某常见离合器部件为例,从理论计算和仿真分析两方面模拟了涡轮起动机环境下的短时受载工况,验证了本文原理和分析模型的有效性,因而对此类离合器的设计与校核分析具有重要意义。

艺术表演中的角色形象与服装设计审美研究

文章系统地探讨了服装设计在艺术表演中塑造角色形象的重要性,深入分析了文化与时代背景如何影响服装设计的创意过程,以及角色形象塑造中服装设计的基本原则。文章还着重考察了当代技术,如数字化设计、3D打印和智能制造在服装设计中的应用,以及个性化与定制化趋势如何改变传统的服装设计和生产方式。通过研究不同领域内成功的角色形象与服装设计案例,展示了服装设计在传达角色内在特质、文化背景和情感表达方面的独特能力,强调了创新与技术在推动服装设计发展中的关键作用。

定点零售药店纳入门诊统筹管理政策对利益相关者的影响分析

目的:为完善定点零售药店纳入门诊统筹管理政策提供依据。方法:基于利益相关者理论,结合文献综述、定性访谈分析定点零售药店纳入门诊统筹管理政策的实施对利益相关者的影响。结果:理想层面,定点零售药店纳入门诊统筹管理政策的顺利实施能够缓解职工医保个人账户改革所带来的冲击,缓解医疗机构就诊压力,提升参保人购药的便利性。然而,受制于政策设计不完善、配套措施跟进不及时等因素,短期内政策产生的实际效果与理想状态存在差异。讨论和建议:医保部门持续收集政策实施的相关反馈,不断优化政策设计;完善政策时以参保人为核心,兼顾多方主体利益;充分了解相关主体的特点和利益关系,强化医保基金监管。

安百拓液压凿岩机活塞受力面积分析与三段法述评

搜集了11个安百拓双控式凿岩机和4个后控式凿岩机冲击活塞的直径数据,计算得到在凿岩机冲击运动周期中,回程与冲程活塞受力面积的比值范围。根据比值数据的分析,指出基于三段法理论的设计变量作为凿岩机性能评价指标的普适性较差。据此,本文强调了数据分析在凿岩机研究中的重要作用。文中还介绍了改进的三段法理论及其计算实例,论述了改进的三段法的优点与缺点。

一种变速度条件下控制攻击角度和时间的制导律

对攻击角度和时间进行控制,可以使得多枚导弹按照特定的角度和时间对目标进行打击,在军事上有广泛的应用前景.目前已有控制攻击角度和时间的制导律极少考虑速度变化的情况,在实际运用中具有较大的局限性.本文基于贝塞尔曲线加直线的二段式轨迹,首先分析并证明了该轨迹长度和最大曲率的变化规律,在此基础上,通过二分法确定初始轨迹,针对飞行过程中的诱导阻力和其它扰动,设计了Bezier-PI控制算法,通过动态调整轨迹长度来实现攻击时间的高精度控制.该制导算法计算量小,鲁棒性强,适用于弹载计算机实时计算.通过仿真实验,验证了该算法可以高精度的控制攻击时间以及攻击角度.