考虑桩顶水平反力的水平受荷单桩弹塑性解析解

基于线性地基反力法和土体的弹塑性本构关系,对桩顶水平反力系数不为零时的水平受荷桩进行了研究,给出了桩顶土屈服临界荷载（水平力、弯矩）的耦合关系式。研究结果表明,当荷载大于临界荷载时,桩顶土发生塑性屈服,其塑性屈服深度随荷载的增加而增加,但其塑性区扩展速率随桩顶荷载的增加而逐渐减小。给出了弹性区与塑性区桩内力耦合的矩阵方程及其迭代求解格式;利用曲面拟合软件给出了塑性区换算深的计算公式。通过工程算例验证,证明该方法可靠快捷,便于手算,值得推广。      

电动振动台试验能力的确认方法研究

研究电动振动台的特性,根据产品振动试验条件提出电动振动台能否满足试验条件的要求,找到电动振动台试验能力范围的确认方法。该文以DC-8000-80电动振动台为实例描述电动振动台能力范围的确认方法研究。     

Perception of Hand Force in Power Grip for Females

Borg's rating of perceived exertion (RPE) and category ratio (CR‐10) scales are commonly used to quantify perceived muscular exertion for body segments. Twenty females participated in an experiment to study the power grip force at four perceived exertion levels using either dominant or nondominant hand under two posture conditions. It was found that the subjects tended to apply a higher power grip force (100% of perceived maximum voluntary contraction) than the levels they were requested to apply. The power grip forces between dominant and nondominant hands at low hand exertion levels were negligible. The grip forces between the two hands were significantly different when the exertion level was nearly maximal. Linear regression models were established for the subjects to link the relationship between the perceived hand exertion and measured grip force, hand used, and hand/arm posture. All the models were statistically significant (p < 0.0001) with R² values 0.97 or higher. These models provided better estimates in perceived hand exertion for dominant hand than for nondominant hand. A follow‐up experiment was conducted to measure the subjective rating of both the CR‐10 and RPE when a 98 N grip force was applied. It was found that the subjects reported higher exertion levels when they were using the CR‐10 scale than when they were using the RPE scale. © 2011 Wiley Periodicals, Inc.     

掏挖基础在强风化砂岩地基中的应用探讨

文章对强风化砂岩抗剪强度指标进行了分析和探讨,提出了用岩体结构面抗剪强度指标折减来获得强风化砂岩的内摩擦角和粘聚力的方法,并结合掏挖基础应用条件,通过计算掏挖基础在强风化砂岩地基应用时扩底成型稳定性,得出在强风化泥质粉砂岩和粉砂岩地区掏挖基础在施工过程中能够掏挖成型并大量应用的结论.     

多层建筑中楼梯部分对整体结构的地震影响分析

楼梯做为建筑结构的重要组成部分,其在使用过程中发挥着极其重要的作用。采用SAP2000有限元软件模拟工程中常见的几种楼梯布置方案进行数学建模,来分析地震对结构影响情况。分析结果表明,楼梯的布置位置不同对结构的内力、位移等有着很大的影响,在设计中应该加以重视。     

Prosthetic Hand Finger Control Using Fuzzy Sliding Modes

In order to improve the life quality of amputees, providing approximate manipulation ability of a human hand to that of a prosthetic hand is considered by many researchers. In this study, a biomechanical model of the index finger of the human hand is developed based on the human anatomy. Since the activation of finger bones are carried out by tendons, a tendon configuration of the index finger is introduced and used in the model to imitate the human hand characteristics and functionality. Then, fuzzy sliding mode control where the slope of the sliding surface is tuned by a fuzzy logic unit is proposed and applied to have the finger model to follow a certain trajectory. The trajectory of the finger model, which mimics the motion characteristics of the human hand, is pre-determined from the camera images of a real hand during closing and opening motion. Also, in order to check the robust behaviour of the controller, an unexpected joint friction is induced on the prosthetic finger on its way. Finally, the resultant prosthetic finger motion and the tendon forces produced are given and results are discussed.     

用力传感器测量固液体的热膨胀系数

根据硅压阻式力传感器的工作原理,用传感器测量固液体热膨胀的微小长度变化量,进而测出了固液体的热膨胀系数,实验结果与公认值相比小于2%。这种方法实现了微小长度变化量的非电量电测,使实验操作简便,改进了传统的实验测量方法,拓展了传感器在普通物理实验中的应用。     

微扑翼飞行中的生物和仿生力传感器述评

随着昆虫飞行机理和仿生扑翼飞行研究的不断进展,理解昆虫的传感系统并研制适于微型扑翼飞行器的仿生传感器逐渐成为目前关注的焦点,而MEMS的快速发展使得研制新型的仿生微型传感器成为可能。简要介绍仿生扑翼飞行中传感系统研究现状,对昆虫飞行中采用的力传感器原理、分类进行了介绍;重点分析了几种典型的力传感器;归纳和总结了基于昆虫毛状传感器、钟状传感器和平衡棒仿生,采用各种MEMS技术研制的微型力传感器的生产工艺和应用特点;探索和展望了仿生力传感器的发展特点和今后的发展趋势。     

多分量力传感器的误差补偿与稳定性考核

为解决杯突试验机夹紧力的校准问题,采用单体式多分量结构设计新型测力传感器,同时采用电路补偿和软件对非线性误差修正来提高传感器的准确度,采用计算机测量系统对多分量力传感器的重复性和稳定性进行考核。测量结果表明:设计的多分量力传感器各分量的重复性不大于0.07%,而长期稳定性优于0.26%。     

电液伺服加载系统的鲁棒控制方法研究

针对舵机的主动运动对电液伺服加栽系统的强干扰所引起的多余力,设计一种鲁棒控制器并结合传统的PID控制方法来进行消除.建立数学模型并进行仿真,结果表明:动态鲁棒补偿器很好地起到了抑制外干扰的效果.