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Development of dimensionless P-I diagram for curved SCS sandwich shell subjected to uniformly distributed blast pressure

Yonghui WANG, Ximei ZHAI

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1432-1445 doi: 10.1007/s11709-019-0566-y

摘要： The curved steel-concrete-steel (SCS) sandwich shell was recently proposed to resist blast loading and it showed better blast resistant performance as compared to flat SCS sandwich shell via developing compressive force along the shell. In this paper, a dimensionless Pressure-Impulse (P-I) diagram was constructed as a convenient tool to predict the damage level of curved SCS sandwich shell subjected to uniformly distributed blast loading. The curved SCS sandwich shell was equivalent to a single-degree-of-freedom (SDOF) system and the equation of motion was established by employing the Lagrange’s equation. To construct the dimensionless P-I diagram, the energy balance method was utilized to yield the pressure and impulse asymptotes and the responses in the dynamic response regime were obtained via employing the SDOF method. Then, the finite element method was employed to validate the developed dimensionless P-I diagram. Finally, the procedures of using the constructed dimensionless P-I diagram to quickly conduct the blast resistant design of curved SCS sandwich shell were presented.

关键词： blast loading     curved steel-concrete-steel sandwich shell     Pressure-Impulse diagram     single-degree-of-freedom method     finite element analysis    

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Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

《机械工程前沿（英文）》 2014年 第9卷 第2期   页码 120-129 doi: 10.1007/s11465-014-0300-3

摘要：

In this paper, error modeling and analysis of a typical 3-degree of freedom translational Parallel Kinematic Machine is presented. This mechanism provides translational motion along the Cartesian X-, Y- and Z- axes. It consists of three limbs each having an arm and forearm with prismatic-revolute-revolute-revolute joints. The moving or tool platform maintains same orientation in the entire workspace due to its joint arrangement. From inverse kinematics, the joint angles for a given position of tool platform necessary for the error modeling and analysis are obtained. Error modeling is done based on the differentiation of the inverse kinematic equations. Variation of pose errors along X, Y and Z directions for a set of dimensions of the parallel kinematic machine is presented. A non-dimensional performance index, namely, global error transformation index is used to study the influence of dimensions and its corresponding global maximum pose error is reported. An attempt is made to find the optimal dimensions of the Parallel Kinematic Machine using Genetic Algorithms in MATLAB. The methodology presented and the results obtained are useful for predicting the performance capability of the Parallel Kinematic Machine under study.

关键词： translational Parallel Kinematic Machine     error modeling     global error transformation index    

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On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 34-40 doi: 10.1007/s11465-014-0290-1

摘要：

As the instant centers in planar mechanisms, the instantaneous poles (or instant poles, in brief) can be used for kinematic analysis in spherical mechanisms. One of the mandatory steps in this analysis is the determination of the location of these poles. This paper presents a theorem showing analytically that the locus of an unknown secondary instant pole in two-degree-of-freedom (2-DOF) spherical mechanisms is a great circle (GC). The exact location of the pole on its GC is obtained based on the configuration of the mechanism and velocity ratio of the two inputs. Moreover, using the results of the theorem, a geometrical technique is presented to determine the GC of the pole.

关键词： spherical mechanisms     instantaneous poles     great circle     angular velocity    

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Stiffness of a 3-degree of freedom translational parallel kinematic machine

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 233-241 doi: 10.1007/s11465-014-0312-z

摘要：

In this paper, a typical 3-degree of freedom (3-DOF) translational parallel kinematic machine (PKM) is studied and analyzed whose tool platform has only translations along X-, Y- and Z-axes. It consists of three limbs, each of which have arm and forearm with prismatic-revolute-revolute-revolute (PRRR) joints. Inverse kinematics analysis is carried out to find the slider coordinates and joint angles for a given position of tool platform. Stiffness modeling is done based on the compliance matrices of arm and forearm of each limb. Using the stiffness modeling the variations of minimum and maximum translational stiffness in the workspace are analyzed. For various architectural parameters of the 3-DOF PKM the tendency of variations on the minimum and maximum stiffness over the entire workspace is studied; and also the deflections of the tool platform along X, Y, and Z directions with respect to various forces are presented.

关键词： 3-DOF translational PKM     inverse kinematics     stiffness modeling     translational stiffness    

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Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

《机械工程前沿（英文）》 2009年 第4卷 第4期   页码 379-385 doi: 10.1007/s11465-009-0075-0

摘要： Singularity analysis plays an important role in the design of robots, especially for parallel robots. In this paper, the direct and inverse kinematics of an orthogonal spherical two-degree-of-freedom parallel mechanism is proposed based on the modified Euler angles. All the singular poses of the mechanism are achieved through the direct kinematic analysis. Self-motions, which are different from the general spherical 5 parallel mechanisms, are also discussed. Singularity loci in the joint space and Cartesian space are plotted according to the Jacobin of the mechanism. Result shows that the singularity loci at the joint space are two circles and one line, whereas at the Cartesian space are a circle.

关键词： 2-DOF orthogonal spherical parallel mechanism     singularity loci     self-motions    

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A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 344-353 doi: 10.1007/s11465-014-0320-z

摘要：

This paper is a detailed exploration of instantaneous poles for a class of two-degree-of-freedom (two-DOF) spherical mechanisms (SMs) with seven links or bars. For two-DOF SMs, the secondary instantaneous poles (the ones which cannot be found by direct inspection) must lie on the specified great circles. For many of these mechanisms, however, some of these great circles cannot be obtained by a direct application of Aronhold-Kennedy theorem. This paper presents geometrical and analytical techniques to locate these unknown great circles for three topologies of seven-bar two-DOF SMs.

关键词： spherical mechanisms     instantaneous poles     Aronhold-Kennedy theorem     great circles     pencil of meridian    

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Design and locomotion analysis of two kinds of rolling expandable mobile linkages with a single degreeof freedom

Yanlin HAO, Yaobin TIAN, Jianxu WU, Yezhuo LI, Yan-An YAO

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 365-373 doi: 10.1007/s11465-020-0585-3

摘要： This study presents two kinds of rolling robots that are able to roll by deforming their outer shapes with a single degree of freedom. Each robot is an essential multi-loop planar expandable linkage constructed by a concave outer loop and several inner parallelogram loops. In this study, the mechanical design of the robots is introduced. Dynamic rolling process is further analyzed on the basis of zero moment point method, and a morphing strategy is proposed to guarantee a stable dynamic rolling process. A novel passive rolling locomotion is also developed, which enables the robots to roll and stand on a slope. To verify the design, two prototypes are manufactured, wherein the dynamic and passive rolling locomotion are carried out.

关键词： rolling locomotion     expandable mechanism     mechanism design     zero moment point (ZMP) analysis    

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An optimized solar-air degree-day method to evaluate energy demand for poultry buildings in different

Yang WANG, Baoming LI

《农业科学与工程前沿（英文）》 2020年 第7卷 第4期   页码 478-489 doi: 10.15302/J-FASE-2019289

摘要：

The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy. This study was designed to optimize the degree-day calculation and proposes a solar-air degree-day method, which can be used to calculate the cooling and heating degree-days and the annual cooling and heating loads under different climate conditions for poultry buildings. In this paper, the solar-air degree-day method was proposed, which considers the effects of solar radiation with different wall orientations and surface colors. Five Chinese cities, Harbin, Beijing, Chongqing, Kunming and Guangzhou, were selected to represent different climate zones to determine the solar-air degree-days. The heating and cooling energy requirements for different climates were compared by DeST (Designer’s Simulation Toolkit) simulation and the solar-air degree-day method. Approaches to decrease energy consumption were developed. The results showed that the maximum relative error was less than 10%, and the new method was not significantly different from the DeST simulation ( >0.05). The accuracy of calculating energy requirements was improved by the solar-air degree-day method in the different climate zones. Orientation and surface color effects on energy consumption need to be considered, and external walls of different orientations should have different surface colors.

关键词： base temperature     energy consumption     solar radiation     orientation     surface color    

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Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Xinzheng LU, Qingle CHENG, Zhen XU, Chen XIONG

《工程管理前沿（英文）》 2021年 第8卷 第1期   页码 122-134 doi: 10.1007/s42524-019-0072-x

摘要： Strong aftershocks generally occur following a significant earthquake. Aftershocks further damage buildings weakened by mainshocks. Thus, the accurate and efficient prediction of aftershock-induced damage to buildings on a regional scale is crucial for decision making for post-earthquake rescue and emergency response. A framework to predict regional seismic damage of buildings under a mainshock–aftershock (MS–AS) sequence is proposed in this study based on city-scale nonlinear time-history analysis (THA). Specifically, an MS–AS sequence-generation method is proposed to generate a potential MS–AS sequence that can account for the amplification, spectrum, duration, magnitude, and site condition of a target area. Moreover, city-scale nonlinear THA is adopted to predict building seismic damage subjected to MS–AS sequences. The accuracy and reliability of city-scale nonlinear THA for an MS–AS sequence are validated by as-recorded seismic responses of buildings and simulation results in published literature. The town of Longtoushan, which was damaged during the Ludian earthquake, is used as a case study to illustrate the detailed procedure and advantages of the proposed framework. The primary conclusions are as follows. (1) Regional seismic damage of buildings under an MS–AS sequence can be predicted reasonably and accurately by city-scale nonlinear THA. (2) An MS–AS sequence can be generated reasonably by the proposed MS–AS sequence-generation method. (3) Regional seismic damage of buildings under different MS–AS scenarios can be provided efficiently by the proposed framework, which in turn can provide a useful reference for earthquake emergency response and scientific decision making for earthquake disaster relief.

关键词： regional seismic damage prediction     city-scale nonlinear time-history analysis     mainshock–aftershock sequence     multiple degree-of-freedom (MDOF) model     2014 Ludian earthquake    

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An efficient method for the dynamic interaction of open structure-foundation systems

LIU Jingbo, GU Yin, LI Bin, WANG Yan

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 340-345 doi: 10.1007/s11709-007-0045-8

摘要： The structure-foundation system is transformed from an original open system into an approximately hermetic system through a viscous-spring artificial boundary. In addition, the seismic wave scattering problem is changed to a wave source problem by employing an equivalent seismic wave input method. Subsequently, the modal superposition method is adopted to solve the approximated hermetic system. This procedure is highly efficient in analyzing dynamic structure-foundation interaction problems in the time domain. Two numerical examples are presented to illustrate the characteristics of the proposed method: one is a wave source problem in 2-dimensions (2-D) elastic semi-infinite space, and the other is a dynamic structure-foundation interaction problem under seismic excitations. Compared with the traditional direct step-by-step integration method, the proposed method, with a sufficient number of modes included, can significantly reduce the computational time with almost the same precision. The results also indicate that the proposed method is more advantageous for solving large structure-foundation systems of many degrees of freedom.

关键词： structure-foundation interaction     superposition     interaction problem     freedom     efficient    

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LCF behavior and life prediction method of a single crystal nickel-based superalloy at high temperature

Zhihua ZHANG,Huichen YU,Chengli DONG

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 418-423 doi: 10.1007/s11465-015-0362-x

摘要：

Low cycle fatigue tests were conducted on the single crystal nickel-based superalloy, DD6, with different crystallographic orientations (i.e., [001], [011], and [111]) and strain dwell types (i.e., tensile, compressive, and balanced types) at a certain high temperature. Given the material anisotropy and mean stress, both orientation factor and stress range were introduced to the Smith, Watson, and Topper (SWT) stress model to predict the fatigue life. Experimental results indicated that the fatigue properties of DD6 depend on both crystallographic orientation and loading types. The fatigue life of the tensile, compressive, and balanced strain dwell tests are shorter than those of continuous cycling tests without strain dwell because of the important creep effect. The predicted results of the proposed modified SWT stress method agree well with the experimental data.

关键词： life prediction     single crystal superalloy     low cycle fatigue (LCF)     crystallographic orientation     strain dwell    

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Evaluation method of multiaxial low cycle fatigue life for cubic single crystal material

CHEN Jiping, DING Zhiping

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 278-282 doi: 10.1007/s11465-007-0048-0

摘要： The coupling effect of normal stress and shear stress on orthotropic materials happens when applied loading deflects from the directions of the principal axes of the material coordinate system. By taking account of the coupling effects, formulas of equivalent stress and strain for cubic single crystal materials are cited. Using the equivalent strain and equivalent stress for such material and a variable k, which is introduced to express the effect of asymmetrical cyclic loading on fatigue life, a low cycle fatigue (LCF) life prediction model for such material in multiaxial stress starts is proposed. On the basis of the yield criterion and constitutive model of cubic single crystal materials, a subroutine to calculate the thermo elastic-plastic stress-strain of the material on an ANSYS platform was developed. The cyclic stress-strain of DD3 notched specimens under asymmetrical loading at 680vH was analyzed. Low cycle fatigue test data of the single crystal nickel-based superalloy are used to fit the different parameters of the power law with multiple linear regression analysis. The equivalent stress and strain for a cubic single crystal material as failure parameters have the largest correlation coefficient. A power law exists between k and the failure cycle. The model was validated with LCF test data of CMSX-2 and DD3 single crystal nickel-based superalloys. All the test data fall into the factor of 2.5 for CMSX-2 hollow cylinder specimens and 2.0 scatter band for DD3 notched specimens, respectively.

关键词： orthotropic     regression analysis     crystal material     multiaxial     prediction    

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Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 224-237 doi: 10.1007/s11709-022-0914-1

摘要： The horizontal bearing behavior of a single batter pile (SBP) is vital to its application in practical engineering; however, the horizontal responses of SBPs change with the directions of horizontal loads, and this phenomenon is rarely investigated. Therefore, the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study. Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs. Subsequently, the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element (FE) analysis. The effects of the skew angle on SBP-soil interaction are discussed. Moreover, an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle, batter angle, and pile diameter. The method is confirmed to be effective, as confirmed by the close agreement between the predicting results with the model test (reported in this study) and centrifuge model test results (reported in the literature).

关键词： single batter pile     skew horizontal load     model test     finite-element analysis     empirical design method    

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二自由度精确解耦离散复矢量永磁同步电机电流控制器 None

Meng WANG, Jia-qiang YANG, Xiang ZHANG, Chang-sheng ZHU

《信息与电子工程前沿（英文）》 2018年 第19卷 第4期   页码 569-581 doi: 10.1631/FITEE.1601390

摘要： 电流控制器性能对永磁同步电机驱动的影响至关重要，然而，在数字处理器中采用传统的连续域电流控制器不能使系统达到完全解耦，这使得电流控制器性能会随电机转速而变化。为提高电流控制器性能，提出一种利用精确离散复矢量模型在离散域直接设计电流控制器的方法。首先，针对变流器输出电压和电机反电势的不同特性推导出永磁同步电机的精确离散模型。然后，根据该模型设计出三阶形式精确解耦二自由度电流控制器，该控制器在配置系统闭环极点时自由度更高。针对两种不同的对消零极点位置选取方案，借助复矢量根轨迹和灵敏度函数对其抗干扰性和参数敏感度进行考察，结果表明两种方案各有优势。最后，在2.5 kW永磁同步电机实验台上验证了所提电流控制器设计方法的有效性。

关键词： 永磁同步电机；离散电流控制器；复矢量    

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六自由度光栅干涉仪中的无偏溯源角表达法 Research Article

常笛1,2,胡鹏程1,2,谭久彬1,2

《信息与电子工程前沿（英文）》 2021年 第22卷 第12期   页码 1551-1684 doi: 10.1631/FITEE.2000432

摘要： 光栅姿态角表达方法是六自由度光栅干涉测量的重要课题，但仅有少量相关研究。目前，广泛用于航空航天、导航和机器人领域的导航角（roll-pitch-yaw）被引入六自由度光栅干涉测量领域。然而，因导航角存在固有旋转顺序，在描述绕多个测量轴的复杂旋转时会引起溯源偏差，且该偏差随光栅偏摆角度增加而增大，并不符合干涉系统中的精确定义。基于机器人领域的融合角（fused angles）表达法，本文提出“无偏溯源角（fused-like angles）”表达法，因无偏溯源角不会引起溯源偏差，更加符合光栅干涉仪中的定义，从而更适合六自由度测量。提出的无偏溯源角已应用于六自由度光栅干涉的运动模型和解耦算法研究。

关键词： 无偏溯源角；光栅干涉仪；六自由度测量；角度表达方法    

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标题 作者 时间 类型 操作

Development of dimensionless P-I diagram for curved SCS sandwich shell subjected to uniformly distributed blast pressure

Yonghui WANG, Ximei ZHAI

期刊论文

Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

期刊论文

On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

Stiffness of a 3-degree of freedom translational parallel kinematic machine

null

期刊论文

Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

期刊论文

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

Design and locomotion analysis of two kinds of rolling expandable mobile linkages with a single degreeof freedom

Yanlin HAO, Yaobin TIAN, Jianxu WU, Yezhuo LI, Yan-An YAO

期刊论文

An optimized solar-air degree-day method to evaluate energy demand for poultry buildings in different

Yang WANG, Baoming LI

期刊论文

Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Xinzheng LU, Qingle CHENG, Zhen XU, Chen XIONG

期刊论文

An efficient method for the dynamic interaction of open structure-foundation systems

LIU Jingbo, GU Yin, LI Bin, WANG Yan

期刊论文

LCF behavior and life prediction method of a single crystal nickel-based superalloy at high temperature

Zhihua ZHANG,Huichen YU,Chengli DONG

期刊论文

Evaluation method of multiaxial low cycle fatigue life for cubic single crystal material

CHEN Jiping, DING Zhiping

期刊论文

Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

期刊论文

二自由度精确解耦离散复矢量永磁同步电机电流控制器

Meng WANG, Jia-qiang YANG, Xiang ZHANG, Chang-sheng ZHU

期刊论文

六自由度光栅干涉仪中的无偏溯源角表达法

常笛1,2,胡鹏程1,2,谭久彬1,2

期刊论文