基于nCode Design-Life的某车架疲劳可靠性分析

针对某型半挂牵引车车架局部出现裂纹或者断裂现象,通过有限元理论和疲劳分析理论相结合进行了车架的有限元分析和疲劳可靠性分析。首先对该车架进行了建模和有限元静态特性分析,然后定义了特定的时间载荷序列数据和材料参数,选用了S-N疲劳设计和静态疲劳分析方法,利用疲劳分析软件nCode Design-Life对该车架进行疲劳可靠性分析,得出该车架的疲劳结果云图和各节点的疲劳寿命,并从相关云图中确定出车架容易破坏的位置和其寿命之后再进行样车实验验证。

基于nCode Design-Life的电动客车车架疲劳寿命分析

针对某型电动客车车架疲劳及寿命问题,本文以有限元理论和疲劳分析理论相结合的方法,对电动客车车架进行静强度分析和疲劳寿命校核,建立有限元模型并进行受力分析,定义特定的载荷谱和材料疲劳数据;同时利用S-N静态疲劳设计方法,选用疲劳分析软件nCode Design-Life对该车架进行疲劳可靠性分析。分析结果表明,该车架的疲劳寿命为1.558×106次,许用行驶里程为650 000km,与公交客运车行驶里程参考值约为400 000km相比,结果满足要求。该研究实现了电动车减重节能,增加了续驶里程,为车架优化设计及寿命模型的建立提供了理论依据。

基于nCode Design-Life的某液压缸疲劳可靠性分析

针对某型径向柱塞马达液压缸工作过程中出现的裂纹现象,在Workbench和n Code Design-Life软件中对液压缸进行有限元分析和疲劳可靠性分析。得出该液压缸的疲劳寿命和疲劳损伤云图,确定液压缸的易破坏位置为轴根部,试验验证结果与软件分析相一致。

基于nCode Design-Life的重型起重设备疲劳寿命预测研究

为研究重型起重设备的疲劳损伤和寿命,以门式起重机为算例建立有限元模型,通过有限元静力学分析,最大等效应力位于跨中受拉区,得出门式起重机强度和刚度满足要求。采用nCode Design-Life疲劳仿真软件利用S-N疲劳设计方法对有限元静力学特性和疲劳损伤进行分析,得到门式起重机疲劳寿命分布云图和疲劳损伤云图,其最小寿命满足工程要求。为了研究载荷变化对起重机寿命的影响,通过改变载荷缩放因子来改变时间载荷序列的大小,对比分析载荷变化后的寿命情况,得出随机载荷减小门式起重机寿命大大增加,过载对门式起重机的疲劳寿命有显著的影响。

基于nCode design-life的某钢结构吊车梁疲劳可靠性

近年来对吊车梁的调查显示,由于吊车梁的受力复杂,钢吊车梁在往复载荷作用下会提前出现不同程度的疲劳裂缝,危害生产安全与降低经济效益,疲劳寿命的研究可以有效的预防和减小破坏等问题的概率并可对于寿命进行延长.本文采用S-N方法,运用ANSYS有限元软件与nCode Design-life疲劳软件相结合的方式,通过对目标吊车梁的实际受力状态进行模拟并对其进行疲劳可靠性分析,找出最易破坏的节点及最不利位置.取吊车梁一端为基准,设置电葫芦在吊车三个不同位置的工况进行分析,得出三组此破坏点的循环数据,其最小循环值则为吊车梁往复载荷后的最易损坏处.

PRODUCT DATA PREDICTION WITH UNCERTAINTY IN PRODUCT LIFE CYCLE DESIGN

Various kinds of data are used in new product design and more accurate datamake the design results more reliable. Even though part of product data can be available directlyfrom the existing similar products, there still leaves a great deal of data unavailable. This makesdata prediction a valuable work. A method that can predict data of product under development basedon the existing similar products is proposed. Fuzzy theory is used to deal with the uncertainties indata prediction process. The proposed method can be used in life cycle design, life cycleassessment (LCA) etc. Case study on current refrigerator is used as a demonstration example.

Design of Accelerated Life Test Plans——Overview and Prospect

Accelerated life test(ALT) is currently the main method of assessing product reliability rapidly, and the design of efficient test plans is a critical step to ensure that ALTs can assess the product reliability accurately, quickly, and economically. With the promotion of the national strategy of civil-military integration, ALT will be widely used in the research and development(R&D) of various types of products, and the ALT plan design theory will face further challenges. To aid engineers in selecting appropriate theories and to stimulate researchers to develop the theories required in engineering, with focus on the demands for theory research that arise from the implementation of ALT, this paper reviews and summarizes the development of ALT plan design theory. The development of the theory and method for planning optimal ALT for location-scale distribution, which is the most applied and mature theory of designing the optimal ALT plan, are described in detail. Taking this as the center of radiation, some problems that ALT now faces, such as the verification of the statistical model, limitation of sample size, solutions of resource limits, optimization of the test arrangement, and management of product complexity, are discussed, and the general ideas and methods of solving these problems are analyzed. Suggestions for selecting appropriate ALT plan design theories are proposed, and the urgent solved theory problems and opinions of their solutions are proposed. Based on the principle of convenience for engineers to select appropriate methods according to the problems found in practice, this paper reviews the development of optimal ALT plan design theory by taking the engineering problems arising from the ALT implementation as the main thread, provides guidelines on selecting appropriate theories for engineers, and proposes opinions about the urgent solved theory problems for researchers.

Empirical Approach for Planning and Designing Constant Stress Accelerated Life Tests

Accelerated life testing(ALT)has been widely used to obtain information about the product's life characteristics at normal conditions in a relatively short period of time.Two key issues with ALT are test design and data analysis.The test design of constant stress ALT was studied in this paper.The test design usually combines engineering experiences with optimization models.Such approaches are hard to be implemented by practitioners.A"pure"empirical approach was presented to address this issue.With the proposed approach,some of the decision variables are determined based on the results from the literature,some of the other variables are determined based on engineering analysis and /or judgment,and the remaining variables are determined based on the empirical relations developed in this paper.A real-world example is included to illustrate the appropriateness of the proposed approach.

Reliability-Based Full-Life Cycle Optimum Design of Offshore Jacket Platform

Based on the consideration of operation environment and structural property, an optimum design model of offshore jacket platform is developed in this paper, namely, the reliability-based full-life cycle optimum design model. In this model, the time-dependent reliability assessment method for structural members is established by combination of the decrease of sectional size and performance deterioration of material. The initial investment, maintenance cost and failure loss cost are assembled into the model. The total cost of the platform structure system in its full service period is chosen as the objective function, and the initial reliabilities of the layer elements partitioned in advance are taken as the design variables. Different models are obtained, depending on whether the system reliability constraint is considered or not. This optimum design model can result in the lowest full-life cost and the optimal initial layer reliability of an offshore jacket platform in the design of marine structures. The feasibility of this model is illustrated with an actual jacket platform in the Liaodong Gulf as an example.

Landscape Design Mode Based on the Integration of Ecology, Production and Life

Taking landscape design of Suburban Park in Yulin City for example, this paper applied the design thoughts of integrating multiple planning, defining concepts and objectives, specified the design strategies of restoring ecology, improving life and promoting production, and disclosed the landscape design mode based on the integration of ecology, production and life in which ecological landscapes, productive landscapes and living landscapes promote and coexist harmoniously with each other.

Optimal Design of Multiple Stress Constant Accelerated Life Test Plan on Non-rectangle Test Region

For optimal design of constant stress accelerated life test（CSALT） with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT design on non-rectangle test region, the present method is only focused on non-rectangle test region with simple boundary, and the optimization algorithm is based on experience which can not ensure to obtain the optimal plan. In this paper, considering the linear-extreme value model and the optimization goal to minimize the variance of lifetime estimate under normal stress, the optimal design method of two-stress type-I censored CSALT plan on general non-rectangular test region is proposed. First, two properties of optimal test plans are proved and the relationship of all the optimal test plans is determined analytically. Then, on the basis of the two properties, the optimal problem is simplified and the optimal design method of two-stress CSALT plan on general non-rectangular test region is proposed. Finally, a numerical example is used to illustrate the feasibility and effectiveness of the method, The result shows that the proposed method could obtain the optimal test plan on non-rectangular test regions with arbitrary boundaries. This research provides the theory and method for two-stress optimal CSALT planning on non-rectangular test regions.

Reflection on Full Life Cycle Green Architectural Design of Passive Priority——Taking the Award Design of China Merchants Property 2013 Green Architectural Design Competition as an Example

In the China merchants property 2013 green architectural design competition,feature of this awardwinning program is the design method based on the principles of passive priority and comprehensive utilization of full life cycle. The passive priority can be achieved by building form derived from the simulation and analysis of wind environment,improvement of the building envelope insulation and the dehumidification of fresh air,the use of solar energy. The full life cycle utilization can be accomplished by the combination of exhibition and residents' leisure activities, and the integration with local cultural tradition, thereby improving energy efficiency and the utilization of the building.

从街道场所到城市区域:美国城市宜居性的研究与实践

“宜居性”是20世纪60年代以来美国人本主义城市设计中的重要议题。区别于现代主义带有浓重乌托邦色彩的宏大城市构想,宜居性理论重点关注微小叙事和日常生活。文章通过详细梳理20世纪60年代以来美国宜居性理论研究和实践的发展历程发现:1996年以前的宜居性研究聚焦于街道—场所尺度,包含两条研究脉络,即从安全的街道到复合型林荫大道和从交往的场所到公共领域的重塑;1996年以后,新城市主义理论的发展推动了“街道—社区—城市—区域”多尺度融合的宜居性研究和实践。在此基础上,对我国的宜居城市建设提出3点启示:以人为本,优化步行和公交系统;关注日常生活,鼓励公共参与;注重多尺度空间要素的一致性和完整性。

小样本加速寿命试验设计与评估方法

针对工程上加速寿命试验仍然存在时间长、试样多的问题,提出一种小样本加速寿命试验设计与评估方法。该方法只需在两个加速应力水平下进行加速寿命试验,即可对产品在正常使用应力水平下高置信度、高可靠度的可靠寿命进行评估。文中首先利用工程上常用的线性加速模型(如阿伦尼斯模型、逆幂律模型和指数模型等)建立了正常使用应力水平下可靠寿命的单侧置信下限与两个加速应力水平下的可靠寿命置信限之间的数学关系式,给出了正常使用应力水平下高置信度、高可靠度的可靠寿命单侧置信下限评估方法。然后分别对指数分布、两参数Weibull分布和对数正态分布的定数截尾加速寿命试验情况进行了详细讨论,给出了相应的正常使用应力水平下高置信度、高可靠度的可靠寿命单侧置信下限计算公式。该方法计算简单,而且对完全数据、不完全数据以及各种分布均适用。大量工程算例和Monte Carlo模拟验证表明,与需要在多个加速应力水平下进行寿命试验的传统方法相比,本文方法不但可以节省大量试样和试验时间,而且理论上更加严谨,精度更高。

医学生“生命关怀与死亡教育”课程的设计与实施

目的:基于医学生的需求设计并开展了“生命关怀与死亡教育”课程,初步评价其效果,以期为国内其他医学院校开展生死教育课程提供参考。方法:以“围死亡期”为时间框架,课程主线贯穿理论内容及实践主题活动,通过“行走的课堂”体验式实践教学方式带领医学生直面生死真实场景,提高照护理念和产生照护行动。结果:课程内容包括“生命与关怀”和“死亡与告别”两大理论授课主题及“生命之旅”“照护力量”“自我关怀”“死亡之思”“告别之日”五大实践授课主题。课程初步实践效果好,多方相关利益人群给予课程高度评价。结论:该课程设计合理,实施方案明确、清晰,在一定程度上满足了医学生对生死教育的学习需求,能够促进医学生对生死问题在思想上的自知和照护行动上的自觉,可推广性强,能够为各医学院校开展生死教育课程提供参考。

2023设计:技术洪流中的文化追寻

2023年,中国经济提质增效持续推进,人工智能设计相关的工具技术广泛应用,设计在产业领域的作用机制、思维方法、价值影响等进一步向系统化、数据化的方向拓展和深化。关于“人机关系”的忧虑反思,也促使设计中“人”之主体的不可替代性成为人们思辨和探寻的焦点。事实上,在技术工具迭代更新的同时,中国设计在文化向度上也在不断深化,呈现出对传统文化设计更新等“场域”式地综合观照与实践。同时,在社会民生领域,设计作为日常生活善与美的优化路径,表现出精微、质实且深刻的意义。整体上,2023年中国设计在技术工具迭代演进的大趋势中实现了从产业运筹到文化精神追寻与建构的新发展。

蛋白质结构稳定性检测的实验课程设计

随着生物技术的突破和发展,多肽蛋白类药物的出现使得人类疾病的诊断和治疗发生了翻天覆地的变化。为了顺应多肽蛋白类药物的飞速发展,加强生命科学等专业本科生对此类药物制剂相关知识的普及已势在必行。此实验课程设计利用稳定性热检测法分析蛋白质结构的稳定性,为生命科学等专业本科生设计一堂深入了解蛋白质结构与功能关系的课程,以促进本科生拓宽学术视野,提升完成相关科学研究和适应医药产业发展新形势的能力。

恒应力加速试验优化设计的工程实现

对加速寿命试验进行优化设计,以提高试验结果的准确性,同时节省试验成本。对加速寿命试验统计分析进行了深入研究,以恒应力加速寿命试验设计优化为例,通过分析方案要素和约束条件等建立了其优化目标函数,为采用智能算法优化恒应力加速寿命试验设计提供了理论基础。首先,确定研究对象为Weibull寿命分布产品恒应力加速试验的优化设计,根据试验目的选取优化目标函数,对优化目标函数进行推导;然后,针对基于解析优化的加速寿命试验设计方法存在的不足,从工程应用角度出发寻求新的优化方法,提出基于模拟退火算法的试验优化设计方法,并给出相应的应用验证实例;最后,通过实例验证,证明了所提出的方法能够在保证优化结果准确的基础上,解决加速寿命试验优化设计的工程应用问题。

多应力小样本加速寿命试验设计与评估方法

针对目前多应力加速寿命试验需要的组合应力水平多、时间长、费用高的问题,提出一种多应力小样本加速寿命试验设计与评估方法。该方法建立了正常使用应力水平下可靠寿命的单侧置信下限与加速应力水平下的可靠寿命置信限之间的数学关系式,给出了正常使用应力水平下高置信度、高可靠度的可靠寿命单侧置信下限计算公式。文中首先针对工程上最常用的双应力情况,分别建立了无耦合和有耦合的双应力小样本加速寿命试验设计与评估方法,它只需在三个(无耦合)或四个(有耦合)组合应力水平下进行加速寿命试验,即可对产品在正常使用应力水平下高置信度、高可靠度的可靠寿命进行评估。然后针对一般的m种应力情况,建立了基于多应力线性加速模型的小样本加速寿命试验设计与评估方法,它只需在m+1个组合应力水平下进行加速寿命试验,即可求得产品在正常使用应力水平下高置信度、高可靠度的可靠寿命单侧置信下限。该方法计算简单,而且对完全数据、不完全数据以及各种分布均适用。大量工程算例和Monte Carlo模拟验证表明,与传统多应力加速寿命试验方法相比,本文方法不但可以节省大量试样和试验时间,而且理论上更加严谨,精度更高。

八十年代家居装饰设计与民众生活方式变迁--以《家具与生活》杂志为对象的考察

通过考察八十年代《家具与生活》杂志,可发现在民众生活方式变迁下家居装饰设计呈现几点时代特征:首先,板式组合家具成为实用、经济的理想产品;其次,小面积居室促成空间优化设计的趋向;再次,“自己设计”和“自己做”投射出个性化的生活态度。更重要的是,家居装饰设计被赋予前所未有的精神价值,成为精神文明建设的重要途径之一,引导人们实践朴素、务实、积极、健康的生活方式。八十年代家居装饰设计与民众生活方式变迁联系紧密,透过这些联系审视设计行为的社会属性,将更深刻地理解“设计作为文化现象”的研究意义。