共查询到20条相似文献，搜索用时 93 毫秒
1.
梁的弹塑性平面弯曲分析包括了塑性力学解题的全部过程。本文以矩形截面简支梁受集中载荷和均布载荷作用发生平面弯曲为例,利用MATLAB强大的做图功能绘制出了梁的弹塑性区的分界线,直观地给出了梁的弹塑性变化的全过程,使学生能更好地理解塑性力学的概念。对塑性力学教学方法和手段进行了探讨。 相似文献
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梁的弹塑性平面弯曲分析包括了塑性力学解题的全部过程.本文以矩形截面简支梁受集中载荷和均布载荷作用发生平面弯曲为例,利用MATLAB强大的做图功能绘制出了梁的弹塑性区的分界线,直观地给出了梁的弹塑性变化的全过程,使学生能更好地理解塑性力学的概念.对塑性力学教学方法和手段进行了探讨. 相似文献
3.
李鹏辉 《湖北广播电视大学学报》1999,(1):78-80
为了分析滚动轴承的弹塑性接触应力．我们对其模型进行了简化．将轴承滚子与套圈的接触简化为压头与半平面的接触。在利用聚碳酸脂材料进行了二维的光弹塑性实验研究后获得了一些有益的结果,掌握了接触表面的应力分布状态,弄清了塑性区随载荷变化的规律。 相似文献
4.
本文着重研究了薄壁零件数控加工工艺的关键技术。根据材料力学原理,求解薄壁零件弹塑性变形临界条件。在保证薄壁零件加工切削力小于极限载荷的条件下,采用最大切削量对其加工,从而实现薄壁零件的高效加工。 相似文献
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基于ANSYS的素土坯墙体抗震性能影响因素分析 总被引：1，自引：0，他引：1
针对素土土坯墙体的抗侧承载力和变形能力影响因素,采用数理统计理论中的正交试验因素分析方法,对素土坯墙体的静力弹塑性有限元非线性数值模拟计算结果进行了对比分析.研究了素土坯墙体厚度、洞口尺寸和竖向载荷对墙体抗侧承载力和变形能力影响程度.结果表明:未开孔的素土坯墙体,墙体厚度和竖向压应力对墙体的极限位移和极限载荷的提高具有同等重要的程度;开孔的素土坯墙体,墙体厚度、竖向压应力和开孔大小,对墙体的变形能力和抗侧承载力的提高程度相比较,竖向压应力的影响较大. 相似文献
6.
采用有限元方法模拟了热载荷下梯度结构硬质合金的弹塑性响应．样品几何模型为二维梯度结构的轴对称圆柱体．通过引入约束因子构建了梯度材料的弹塑性本构方程．数值模拟表明：当材料温度从初始无应力的800℃下降到0℃时,在样品表面出现了压应力而在富钴区出现了拉应力;表面压应力的最大值为254MPa,富钴区拉应力的最大值为252MPa;在钴相浓度差等于或大于0．3时,钴相梯度区出现了明显的塑性流动;当温度从0℃上升到800℃时,总的塑性应变达到0．0014．塑性流动有利于降低材料内部的热应力集中． 相似文献
7.
《实验室研究与探索》2013,(12)
对低碳钢材料带孔薄壁圆管试样采用逐级加载试验方法,得出其在室温下的单轴循环应力-应变本构关系。利用有限单元法对圆管试样进行弹塑性分析,采用Von Mises屈服准则、多线性随动强化模型,并结合试验获得的本构关系来定义材料的弹塑性特性。拉扭应变载荷加载在柱坐标下进行,采用一端固定,另一端加轴向位移与周向位移的方式。分别在纯拉、纯扭以及拉-扭比例加载下计算出应力应变场,获得不同受力情况下不同孔径尺寸试样在缺口处的应力应变分布。计算结果为多轴加载疲劳试验和复杂应力状态下工程零部件的疲劳寿命预测与分析提供基本数据。 相似文献
8.
针对弹塑性接触问题所构造的等价变分不等式,解除了弹塑性本构状态约束方程和接触状态约束方程的约束.首先证明了所构造泛函的强制性,从而证明了所构造的等价变分不等式解的惟一性,并根据椭圆型变分不等式解存在的充分条件论证了弹塑性接触问题解的存在性,为该问题的变分极值原理的建立奠定了数学理论基础.所构造的变分极值形式为运用数学规划法求解弹塑性接触问题提供了理论保证. 相似文献
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10.
巷道掘进工作破坏了周围原岩应力分布产生了松动圈,对松动圈弹塑性应力分布和范围进行理论分析,得到松动圈弹塑性应力分布半径并进行了讨论。 相似文献
11.
应用广义图乘法分析荷载与连续梁三弯矩方程关系.若杆内有对称荷载,则三弯矩方程简单;简支梁弯矩图的面积能表示荷载对连续三个支座弯矩的作用.任意荷载的作用含反对称荷载分量的图乘剪力的作用.若杆内荷载是同方向,则反对称荷载比弯矩图面积的影响小. 相似文献
12.
Alexander Skulmowski 《Mind, Brain, and Education》2023,17(3):165-169
Cognitive load measurement is an important aspect of educational research. Current cognitive load surveys differentiate between intrinsic cognitive load (resulting from the complexity of learning materials) and their extraneous cognitive load (which is increased by a demanding design). In two studies, order effects of cognitive load subscales are demonstrated. Asking learners regarding their intrinsic load first increases their responses concerning this type of load, with little effect on extraneous load ratings. This effect can be replicated even when extraneous load is intentionally induced. This finding has important implications for cognitive load research, as the order of surveys appears to bias cognitive load ratings. As most cognitive load research is conducted to find ways of reducing extraneous load, it may be reasonable to carefully consider whether and when intrinsic load items are included in studies. Generally, the results show that study participants seem to emphasize certain demands, similar to a dialogue. 相似文献
13.
Robert R. Whelan 《Educational Research Review》2007,2(1):1-12
This paper reviews research literature on cognitive load measurement in learning and neuroimaging, and describes a mapping between the main elements of cognitive load theory and findings in functional neuroanatomy. It is argued that these findings may lead to the improved measurement of cognitive load using neuroimaging. The paper describes how current measures of cognitive load cannot accurately show the distinction between different types of cognitive load in different learning conditions, and existing approaches to cognitive load assessment are limited in terms of their precision and methodology. A literature review discusses the conceptual framework of Sweller's [Sweller, J. (1994). Cognitive load theory, learning difficulty, and instructional design. Learning and Instruction 4, 295-312; Sweller, J. (1999). Instructional design in technical areas. Camberwell, Australia: ACER Press] cognitive load theory, and describes various approaches to load measurement and their limitations. The paper then describes how the core components of cognitive load - intrinsic, extraneous, and germane load - may be observable using neuroimaging techniques, and argues for the exploration of new links between education research and neuroscience. 相似文献
14.
为了达到最佳的负载均衡效果，将负载分给多个服务器分担，负载控制器需要根据网络流量状态和服务器资源来分配负载，这就需要应用优化的负载分配策略，达到平均分配负载的目的，本文讨论了特定流量条件下网关数目的计算模型，分布式路由策略实现负载分配的策略的方法，并研究了基于网络地址转换在Free BSD unix环境下实现负载均衡网关的方法。 相似文献
15.
Sewage source heat pump unit operates under partial load most of the time, and study on the law of coefficient of performance (COP) of the unit varying with load ratio can provide basis for the heat pump units running in high efficiency. A mathematical model determining COP, evaporation temperature and condensation temperature of a single unit was proposed. Under the condition of uniform load distribution, the model was established according to different ways of bearing partial load with the same type multiple units but different parallel operation models, and the operation characteristics of units were analyzed as well. Results show that the single screw water-source heat pump can maintain high COP only at 60%—100% load ratio, COP decreases sharply with the decrease of load ratio, and the units with parallel operation are controlled by the load ratio of a single unit according to the reduction of total load which can keep the average COP at high level within a wide load range. 相似文献
16.
建立了T形配钢型钢混凝土偏压构件力学性能分析的有限元模型,计算结果得到以往实验结果的验证。在此基础上,分析了不同阶段材料应力状态和各参数对偏压构件力学性能的影响。结果表明:T形配钢型钢混凝土构件在不同加载角下的性能有所不同,加载角为180°时极限承载力大于其他角度情况;混凝土抗压强度、型钢含钢率、配筋率、荷载偏心率、长细比对构件荷载-变形曲线的影响较大,随着混凝土强度、型钢含钢率、配筋率的增加,极限承载力和刚度增加;随着荷载偏心率的增加,极限承载力和刚度下降;随着构件长细比的增加,构件承载力总体呈现线性下降趋势,刚度下降明显。 相似文献
17.
赖学江黄森炜廖洪毅曹智校陈清云 《福建工程学院学报》2021,(4):372-377
以深圳某办公楼为例,探讨冰蓄冷空调系统运行策略的优化。采用鸿业全年负荷计算及能耗分析软件(HY-EP)进行全年动态负荷模拟,对冷负荷的负荷率进行分析。在选定冰蓄冷系统后,基于模拟结果和地区的峰谷平电价的特点,采用了基于全年动态负荷结果分析预测和结合前一天的负荷作为当日的负荷预测,将全年逐日运行策略简化为4 种设备的运行方案,控制较为容易实现,且需要增加的初投资较少,是结合冰蓄冷系统与全年动态负荷模拟技术的创新应用。 相似文献
18.
Many online videos feature an instructor on the screen to improve learners' engagement; however, the influence of this design on learners' cognitive load is underexplored. This study investigates the effects of instructor presence on learners' processing of information using both subjective and psychophysiological measures of cognitive load. Sixty university students watched a statistics instructional video either with or without instructor presence, while the spontaneous electrical activity of their brain was recorded using electroencephalography (EEG). At the conclusion of the video, they also self‐reported overall load, intrinsic load, extraneous load, and germane load they experienced during the video. Learning from the video was assessed via tests of retention and transfer. Results suggested the instructor‐present video improved learners' ability to transfer information and was associated with a lower self‐reported intrinsic and extraneous load. Event‐related changes in theta band activity also indicated lower cognitive load with instructor‐present video. 相似文献
19.
为满足对直流电源试验要求,提出了一种采用滞环控制的恒流电子负载模拟功率负载系统的方法,用该方法研制了恒流电子负载装置.试验结果表明,该恒流电子负载能根据所设定的负载性质自动调节负载电流,满足直流电源的试验要求. 相似文献
20.
利用影响线计算力偶作用时梁的内力和反力 总被引：1，自引：0，他引：1
刘永丰 《扬州职业大学学报》2007,11(4):28-30
将力偶分解为等值、反向、平行的两个力,当荷载(集中荷载、分布荷载和力偶)位置已知时,利用影响线计算梁的内力和反力,并与截面法计算结果作一比较。 相似文献