非线性隐式极限状态方程失效概率计算的组合响应面法

提出组合响应面的新方法,用以计算设计点附近非线性程度较大的隐式极限状态方程的失效概率。该方法用主响应面和多个次响应面近似对失效概率贡献较大的区域,其响应面函数形式为不含交叉的二次多项式。主响应面依据传统响应面法通过选择适当的插值点和迭代运算获得,其设计点为主设计点。延坐标轴正负方向偏移主设计点得到拟均值点。以拟均值点为基础得到一组次响应面和次设计点。通过主次响应面在各自设计点处的切平面建立组合响应面近似原隐式极限状态方程,并计算其失效概率。算例结果说明所提方法具有较高精度。     

基于变分迭代法的悬挂式弹簧系统的跌落破损评价

以悬挂式弹簧系统为研究对象,应用变分迭代法求解系统跌落冲击无量纲动力学方程,得到了系统无量纲位移、加速度响应一阶近似解析解,无量刚位移响应峰值,无量纲加速度响应峰值和无量刚跌落冲击持续时间表达式,与龙格-库塔数值分析结果进行了比较。 结果表明,无量纲加速度响应曲线吻合程度较好,无量纲加速度响应峰值和无量刚跌落冲击持续时间相对误差小于 4% 和 2% 。 建立了包含系统参数、产品脆值、无量纲跌落冲击速度、系统悬挂角等多变量的跌落冲击破损评价方程。 以无量纲跌落冲击速度和系统参数为基本评价量,获得了系统跌落破损边界曲线;以无量纲跌落冲击速度、系统参数和初始悬挂角为基本评价量,获得了系统跌落破损边界曲面。 结果表明,随着系统初始悬挂角减小,系统安全性能提高,悬挂系统几何非线性特性对产品保护性能优于线性系统。 为悬挂式系统缓冲设计提供了理论依据。     

管道修复用涤纶-苎麻非织造物/环氧树脂复合材料厚度设计

管状涤纶-苎麻非织造物/环氧树脂复合材料的厚度大小对管道修复后的介质过流能力、内衬材料强度会产生一定的影响,本文根据曼宁方程和复合材料管道设计原则建立了厚度、过流能力及强度的计算公式。采用响应曲面法优化涤纶-苎麻非织造物的制备工艺,在单因素试验的基础上,根据Box-Behnken试验设计原理,选取混杂比、纤网定量、针刺密度3个因素,依据回归分析方程来确定各制备工艺的主要影响因素,以涤纶-苎麻混杂非织造物的厚度和强度为响应值作响应面和等高线图,得出涤纶-苎麻非织造物制备的最优工艺条件（混杂比为0.8,纤网定量为600 g/m2,针刺密度为300 needle/cm2）。在该工艺下,涤纶-苎麻非织造物的厚度为4.14 mm,纵向拉伸强度为2.81 MPa,横向拉伸强度为1.72 MPa,接近理论值,表明响应曲面法具有实际应用价值;结合涤纶-苎麻非织造物/环氧树脂复合材料厚度、强度来验证厚度、过流能力及强度等计算公式的合理性,发现满足管道修复后过流能力的前提下,较薄的涤纶-苎麻非织造物/环氧树脂复合材料的强度能达到翻衬修复排水或排污管道工作压力的需求。      

振动特性参数对单自由度系统振动响应的影响

目的 为研究弹簧刚度、阻尼比和振动偏心距离不同振动特性参数对单自由度线性系统振动响应幅值的影响。方法 首先采用单因素实验,研究弹簧刚度、阻尼比和振动偏心距离对单自由度线性系统振动响应幅值的影响;在此基础上,通过采用Design Expert 11.0软件的响应面法实验（三因素三水平实验）研究不同振动特性参数交互作用对振动响应幅值的影响,建立振动响应幅值的二次多项式回归数学模型,并对减振幅值进行优化。结果 通过实验分析得到,各因素对振动响应幅值的影响强弱顺序,阻尼比>弹簧刚度>振动偏心距离;建立了检测点的响应方程,检测点的回归方程决定系数为0.981;得到多目标参数优化结果,弹簧刚度为2.009 N/mm,阻尼比为0.1,振动偏心距离为12.38 mm。结论 实验结果与预测值接近,说明此响应面法得到的数学回归模型具有一定的可靠性,该研究可为缓冲包装参数设计提供参考。     

双链式悬索桥地震反应特征研究

双链式悬索桥采用钢加劲梁和钢筋混凝上索塔,使得阻尼在全桥中呈非经典阻尼耗能特性,导致主坐标系中的运动方程耦联。基于复阻尼理论求解等效粘滞阻尼比,以近似描述非经典阻尼体系的阻尼耗能特性。考虑几何非线性及非经典阻尼因素,对一座双链式悬索桥进行了地震反应谱和时程反应分析。引入主缆形状系数,将单链式悬索桥作为双链式悬索桥的特例,就同跨度同矢高的双链式悬索桥和单链式（普通式）悬索桥地震反应进行对比分析,揭示双链式悬索桥地震反应特征。双链式悬索桥地震反应特征的研究对该类桥设计选型、动力性能评估及抗震加固设计都有重要的工程意义     

某载重卡车悬架参数优化及试验研究

为了研究多轴载重卡车悬架总成刚度、阻尼之间的匹配和优化问题,提出了一套基于ADAMS软件的适用于重型载货汽车悬架系统的优化设计方法。利用机械系统动力学仿真软件ADAMS/View建立了某8×4载货卡车频域仿真模型,对其满载时以B级随机路面谱作为激励的加速度响应特性进行了仿真分析,并根据所提出的优化方法对该车悬架系统参数进行了优化计算。最后,通过实车道路试验验证了所建模型的正确性和优化方法的可行性,为重型卡车底盘系统集成优化匹配设计提供重要参考价值。     

曲线齿线圆柱齿轮啮合数学模型

参照圆弧齿线圆柱齿轮齿面方程的推导方法以及齿面组成特点,介绍了一类曲线齿线圆柱齿轮的齿面组成特点.采用齿轮啮合原理中的单参数曲面包络方法,运用坐标变换推导了曲线齿线圆柱齿轮的数学方程和共轭齿面方程的一般形式.以圆弧齿线圆柱齿轮的齿面方程推导为例,推导了圆弧齿线圆柱齿轮的空间啮合数学模型,并采用UG建模软件建立了圆弧齿线圆柱齿轮的3D模型,验证了该方法的正确性.研究结果为进一步开展新型齿线的设计、新型曲线齿线圆柱齿轮传动研究提供了理论基础.     

Optimization of coag-flocculation processes of a newly synthesized quaternized oil palm empty fruit bunch cellulose by response surface methodology toward drinking water treatment process application

An optimization of coagulation and flocculation of kaolin suspension by a newly synthesized quaternized oil palm empty fruit bunch cellulose denoted as a 9QC was investigated using the central composite design of the response surface methodology. The influences of coag-flocculant dosage, pH, and kaolin suspension on turbidity removal efficiency and sludge volume index responses were studied and assessed according to a 2³ full factorial design. The developed quadratic models revealed that the overall optimum values to obtain the highest performance of the responses were 62.5 mg/L of coag-flocculant dosage, pH 7, and 1400 mg/L of kaolin concentration. The predicted optimum responses were found to be in close proximity to the observed responses. The coag-flocculating of river water using 9QC carried out at the optimum values showed encouraging results as compared to alum which is commonly used in drinking water treatment process.     

Development of extended zero-order release gliclazide tablets by central composite design

The purpose of this study was to develop an extended release tablet formulation containing gliclazide as a model drug by optimization technique. A central composite design was employed with pH-dependent matrix forming polymers like keltone-HVCR (X1) and eudragit-EPO (X2) as independent variables. Five dependent variables were considered: hardness, percent drug release after 1 hr, percent drug release after 6 hr, diffusion exponent and time required for 50% of drug release. Response surface methodology and multiple response optimization utilizing a quadratic polynomial equation were used to obtain an optimal formulation. The results indicate that Factor X1 along its interaction with Factor X2 was found to be significantly affecting the studied response variables. An optimized formulation, containing 8 mg of keltone-HVCR and 14.10mg of eudragit-EPO, provides a sufficient hardness (> 4.5 kg/cm2) and optimal release properties. The desirability function was used to optimize the response variables, each having a different target and the observed responses were highly agreed with experimental values. The release kinetics of gliclazide from optimized formulation followed zero-order release pattern. The dissolution profiles of optimized formulation before and after stability studies were evaluated by using similarity factor (f2) and were found to be similar. The results demonstrate the feasibility of the model in the development of extended release dosage form.     

一种含螺旋飞轮运动转换器的悬架的振动控制性能分析

为了提升被动悬架的道路振动响应特性,提出一种并联螺旋飞轮运动转换器的新型悬架系统。对螺旋飞轮运动转换器的动力学特性进行了分析,在传统机电比拟理论的基础上,采用自由电容元件来比拟封装螺旋飞轮的运动、转换和质量特性。采用机械网络综合的方法,建立并联运动转换器的车辆悬架状态空间模型,进行参数优化设计以分析悬架对道路振动激励的最优控制性能。对实例性能分析表明,所提出的新型悬架可以有效提升综合性能,为悬架的设计提供了新的思路。     

悬挂式弹簧系统跌落冲击问题的变分迭代法

以悬挂式弹簧系统为研究对象,建立跌落工况无阻尼条件下系统的无量纲几何非线性动力学方程。应用变分迭代法求解动力学方程,得到系统无量纲位移、无量纲加速度1阶近似解析解。跌落工况下系统无量纲位移最大值、无量纲加速度最大值及无量纲跌落冲击时间与椭圆积分法的结果比较,误差在4 %以内。讨论跌落高度和系统悬挂角对无量纲位移最大值和无量纲加速度最大值的影响,研究表明,在相同跌落高度条件下,适当减小系统的悬挂角度,可降低系统无量纲加速度最大值,但无量纲位移最大值增加。研究结论可为悬挂式弹簧系统缓冲设计提供理论依据。     

Response Surface Methodology as an Approach to Optimization of an Oral Solution

Response surface methodology was used to optimize the cloud point and turbidity of a nonionic surfactant solution that had been used to solubilize a very slightly water soluble drug. A formulation suitable for oral administration with turbidity less than four parts per million and cloud point greater than 60°C was desired. A first-order experiment, specifically, a 2⁴ factorial with four center points, was designed to investigate the effect of four formulation components that had been identified as the most likely to affect turbidity and cloud point. When lack-of-fit tests for the first order linear model indicated that a second-order model would provide a better approximation to the response surface in the experimental region, a central composite design with six center points was run in order to fit second-order linear models. Within the experimental region of the second-order design, a simple first-order linear model with the concentration of one component was adequate to describe the cloud point response function; turbidity was fitted with a three component second-order response equation. Experimental runs were performed to confirm the optimum combination of components predicted by the fitted response functions. Response surface methodology provided an efficient approach to development of a nonionic surfactant solution with turbidity less than 4 ppm and cloud point greater than 60°C while maintaining the concentration of formulation ingredients within ranges suitable for oral administration     

扇贝超高压脱壳工艺参数优化研究

为了研究超高压技术在扇贝脱壳领域的应用,对预处理过的扇贝施 加 200~400 MPa 的高压并保持 0~300 s,利用均匀试验法,选择 2 因素 11 水平的均匀试验表对试验条件进行设计。通过检测扇贝的得肉率、持水率、 TVB-N 值和菌落总数等指标,建立试验因素与各指标之间的回归方程,并 利用响应面曲线对扇贝超高压处理时的工艺参数进行优化,求出了各指标 取极值时所对应的试验压力和保压时间,以得到扇贝超高压处理的最佳工 艺参数。根据计算结果,在超高压处理扇贝的过程中,试验压力设置为 300 MPa,保压时间为 180 s 时,扇贝可以得到较高的脱壳率和得肉率,又可以 保持较高的营养价值和储存品质。     

Optimization of propranolol hydrochloride sustained-release pellets using box-behnken design and desirability function

The objective of the present study was to evaluate three process parameters for the application of ethylcellulose films from organic solutions to obtain multi-particulate controlled drug delivery of propranolol hydrochloride. The coating process was developed in a classical coating pan. A Box-Behnken central composite design was used to evaluate the effect of the film thickness (expressed as the amount of lacquer applied on pellets' surface unit), concentration of lacquer in the coating dispersion, and the plasticizer concentration on the independent variables. Those were t85, the degree of sticking in the coating pan, and the duration of the coating process. Contour and response surface plots were depicted based on the equation given by the model. Because the results were competitive, i.e., improving one response had an opposite effect on another one, an overall desirability function was described to ameliorate the interpretation of the results. The optimization procedure generated the maximum overall desirability value. A formulation was prepared under the optimized conditions yielding response values which were close to the predicted values. To understand the mechanism of drug release from the optimized pellets various models were used to fit the dissolution data. The Higuchi model appears to provide the best correlation.     

基于改进响应面法的公路简支梁桥地震易损性分析

针对典型公路简支梁桥提出了一种基于改进响应面方法的易损性模型建构流程。在充分考虑结构和材料等桥梁参数不确定性基础上,基于Plackett-Burman设计方法生成一系列试验样本。采用OpenSees软件进行非线性动力时程分析,比较输入参数对地震响应的贡献,筛选出影响桥梁地震响应的显著性参数;进一步针对显著性参数进行中心复合设计并设计出一系列桥梁样本,基于非线性时程分析结果,建立桥梁各构件在不同的地震动强度下的响应面模型,并采用蒙特卡罗抽样方法计算得到桥梁构件的易损性曲线。假定简支梁桥系统为串联系统,计算生成全桥的易损性曲线。针对相同的桥梁样本,以非线性增量动力分析法生成的易损性曲线为基准,对传统响应面法与改进响应面法计算得到的易损性结果进行比较。结果表明:改进的响应面方程可以高效地替代复杂的非线性时程分析,提高了地震易损性分析的计算效率;构建的易损性曲线能够在较大的地震动强度范围内确定桥梁的损伤构件,帮助桥梁管理部门制定相应的震后加固优先级决策,具有一定的工程应用价值。     

Quality by design approach for development of suspension nasal spray products: a case study on budesonide nasal suspension

The objective of this study was to provide quality by design (QbD) approach for development of suspension type nasal spray products. Quality target product profile (QTPP) of test product budesonide nasal suspension (B-NS) was defined and critical quality attributes (CQAs) were identified. Critical formulation, process and delivery device variables were recognized. Risk assessment was performed by using failure mode and effect analysis (FMEA) methodology. Selected variables were further assessed using a Plackett Burman screening study. A response surface design consisting of the critical factors was used to study the interactions between the study variables. Formulation variable X₂: median particle size of budesonide (D₅₀) (µ) has strikingly influenced dissolution (%) (Y₁), while D₅₀ droplet size distribution (µm) (Y₂) was significantly impacted by formulation variable X₁: Avicel RC 591 (%) and process variable X₄: homogenization speed (rpm). A design space plot within which the CQAs remained unchanged was established at lab scale. A comprehensive approach for development of B-NS product based on the QbD methodology has been demonstrated. The accuracy and robustness of the model were confirmed by comparability of the predicted value generated by model with the observed value.     

鲜食葡萄电商悬固包装薄膜的力学性能分析与优化设计研究

目的 针对电商物流包装存在操作繁琐、透气透湿不足、寄递中暴力分拣的问题以及葡萄易落粒损伤的特点,设计一种针对鲜食葡萄的透气透湿性适宜的简便化包装。方法 采用激光打孔调整TPU薄膜透气透湿性,通过力学性能测试选出适宜厚度与孔隙排列方式,根据跌落试验确认TPU薄膜包裹葡萄的最佳凹陷程度,并验证悬固包装的有效性。结果 厚度为0.08 mm、孔隙排列方式为Z形的TPU薄膜有优良的力学性能与透气透湿性,打孔后薄膜水蒸气透过率极显著提高(P<0.01),并且0.08 mm的Z形TPU薄膜凹陷3 cm的悬固包装在610 mm的高度跌落不触底,对葡萄的保护效果良好。纸浆模塑盒可承受400 N以上的力,循环压缩20次后仍有很好的支撑性,通过跌落测试可得悬固包装葡萄的表面损伤指数比袋中袋更小。结论 综合来看,该悬固包装操作方便,打孔后透气透湿性显著提高,与包装箱匹配使用能满足堆码与运输要求,是一种符合包装运输要求的鲜食葡萄电商包装方式,本研究为果蔬类产品的电商包装结构设计提供了新思路。     

地震作用下千米级高速铁路悬索桥行车安全性研究

为研究地震作用下超大跨铁路悬索桥桥上列车的行车安全问题,以某主跨为1 120 m的公铁两用悬索桥方案为研究对象,采用虚拟横梁法建立了全桥梁格模型,并通过板梁组合模型验证了梁格模型的正确性。在此基础上,通过输入7条地震波,采用自主编制的列车-轨道-桥梁-地震分析程序TTBSAS进行仿真计算,研究了一致激励、行波激励下悬索桥-列车系统的动力响应特征,分析了列车过桥时的行车安全性。结果表明:对于悬索桥-列车系统,地震对桥梁和轨道动力响应的影响大于车辆;横向地震除了使钢桁梁主梁及桥上轨道发生大幅横向振动外,还会诱发主梁的附加扭转振动;不考虑地震行波效应会严重低估列车的行车安全性指标。对于这些计算条件,桥上列车行车安全性研究的最不利行波波速为500 m/s,在0.15g设计地震作用下列车通过主跨1 120 m悬索桥时的安全车速阈值为300 km/h。     

Packaging Parameters Analysis for the Fatigue Reliability of Stacked Chip Ball Grid Array by Using the Optimal Equivalent Solder Balls

A global/local method with the modified sub‐modeling approach of the two‐parametric optimal equivalent volume solder balls is introduced to predict the deformation and reliability of the package. The equivalent solder balls as exhibit in this method can obviously reduce the required elements/nodes quantities to enhance computing efficiency. A package model of wire‐bonded stacked chip ball grid array under cyclic thermal loading is used as a test vehicle to verify the influences of design factors by fatigue life indicator. Comparing the proposed method with the global fine mesh model, it is found that the difference in the accumulated strain energy density is merely 5.77%, but the optimal equivalent model has highly saved 90% finite element analysis required elements, which means the adopted method can effectively replace the global fine mesh model because both results are in accordance with each other. Using design of experiments to efficiently verify each factor influence with their cross‐coupling effects, this paper adopts two kinds of response surface methods that confirm the fatigue life of the proposed approach can be improved by as much as 123.7% for the dual response surface method and 126.3% for the mixed response surface method when comparing with the baseline model. In addition, the optimization of generic algorithm for both response surface methods is demonstrated in this study. From the reviews of factor coupling effects, it is concluded that the response surface method is eligible to achieve the optimum design for package reliability improving. Copyright © 2013 John Wiley & Sons, Ltd.     

梧桐树粉尘爆炸特性研究

以梧桐树粉尘为例,研究了可作为工业粉状炸药添加剂的木粉粉尘的爆炸特性。运用哈特曼管测试了粉尘云的最小点火能,得出样品1#、样品2#和样品3#的最小点火能分别为70、90 m J和150 m J。将响应面法中的Box-Behnken试验设计应用于粉尘爆炸压力的测试,用20 L爆炸球进行试验,并从试验结果中拟合回归方程,由此判断出粉尘浓度对爆炸压力的影响最大,其次是点火能量,再次是粉尘粒径。对爆炸压力的试验条件进行优化,试验测得压力值为0.795 9 MPa,试验值与预测值之间的误差仅为1.28%,证明了该模型非常有效。