Tianjin Automotive Test Center & National Passenger Car Quality Supervision and Inspection Center——A State Testing and Universality Techniques Research Base in China

Tianiin Automotive Test Center has a test capability as well as a capability of conducting universality techniques research. With fixed assets of around RMB 76.44 million yuan and an architectural area of 11,200 sqm, test labs mainly include: auto emission test lab, full-scale vehicle crash test lab, auto safety test lab, auto lighting and view field test lab, engine test lab,

Real-time embedded software testing method based on extended finite state machine

The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliability. Based on the analysis of the characteristics of real-time embedded software, the formal method is introduced into the real-time embedded software testing field and the real-time extended finite state machine （RT-EFSM） model is studied firstly. Then, the time zone division method of real-time embedded system is presented and the definition and description methods of time-constrained transition equivalence class （timeCTEC） are presented. Furthermore, the approaches of the testing sequence and test case generation are put forward. Finally, the proposed method is applied to a typical avionics real- time embedded software testing practice and the examples of the timeCTEC, testing sequences and test cases are given. With the analysis of the testing result, the application verification shows that the proposed method can effectively describe the real-time embedded software state transition characteristics and real-time requirements and play the advantages of the formal methods in accuracy, effectiveness and the automation supporting. Combined with the testing platform, the real-time, closed loop and automated simulation testing for real-time embedded software can be realized effectively.

A PREDICTION OF THE VORTEX-RING STATE BOUNDARY BASED ON MODEL TESTS

To understand the vortex-ring state and to develop an approach for predicting its boundary, a series of model rotor tests of vertical descent and oblique descent have been conducted on a newly-built test apparatus - the Whirling Beam. The test results showed some unsteady aerodynamic behavior of the model rotor operating in the vortex-ring state. A very irregular variation of the rotortorque at low rate-of-descent was observed here for the first time. We considered it to be the start of the 'power settling' and determined the critical descent velocity according to this observation. A previous criterion for the vortex-ring state was modified to give a semi-empirical method for predicting the entire vortex-ring state boundary. The computed boundary shows a good correlation with the model test results and the flight experiences.

Impact of Typical Steady-state Conditions and Transient Conditions on Flow Ripple and Its Test Accuracy for Axial Piston Pump

The current research about the flow ripple of axial piston pump mainly focuses on the effect of the structure of parts on the flow ripple. Therein, the structure of parts are usually designed and optimized at rated working conditions. However, the pump usually has to work in large-scale and time-variant working conditions. Therefore, the flow ripple characteristics of pump and analysis for its test accuracy with respect to variant steady-state conditions and transient conditions in a wide range of operating parameters are focused in this paper. First, a simulation model has been constructed, which takes the kinematics of oil film within friction pairs into account for higher accuracy. Afterwards, a test bed which adopts Secondary Source Method is built to verify the model. The simulation and tests results show that the angular position of the piston, corresponding to the position where the peak flow ripple is produced, varies with the different pressure. The pulsating amplitude and pulsation rate of flow ripple increase with the rise of pressure and the variation rate of pressure. For the pump working at a constant speed, the flow pulsation rate decreases dramatically with the increasing speed when the speed is less than 27.78% of the maximum speed, subsequently presents a small decrease tendency with the speed further increasing. With the rise of the variation rate of speed, the pulsating amplitude and pulsation rate of flow ripple increase. As the swash plate angle augments, the pulsating amplitude of flow ripple increases, nevertheless the flow pulsation rate decreases. In contrast with the effect of the variation of pressure, the test accuracy of flow ripple is more sensitive to the variation of speed. It makes the test accuracy above 96.20% available for the pulsating amplitude of pressure deviating within a range of ~6% from the mean pressure. However, with a variation of speed deviating within a range of ±2% from the mean speed, the attainable test accuracy of flow ripple is above 93.07%. The model constructed in this research proposes a method to determine the flow ripple characteristics of pump and its attainable test accuracy under the large-scale and time-variant working conditions. Meanwhile, a discussion about the variation of flow ripple and its obtainable test accuracy with the conditions of the pump working in wide operating ranges is given as well.

Ultrasonic Nondestructive Testing of Superplastic Solid-State Welding Joint for Different Steels

Based on quantitative microscopic examinations of welds and welding rate for different steels(40Cr and T10A) joint,which possess the ultra-fine microstructure after high frequency hardening(HFH) and salt-bath cyclic quenching(SCQ),the suitable defect grey scale threshold value was determined,and the welding rate of superplastic solid-state welding of different steels(40Cr and T10 A steel) was systematically inspected and analyzed by means of self-made ultrasonic imaging inspection system.The experimental results showed that the superplastic solid-state weld of different steels can be inspected more accurately,reliably and quickly by this system,and the results were in good accordance with that of metallographic observation.The welding rate of superplastic welding is in linear relation with tensile strength of joint.

Adding Transitions of Undefined States to State Transition Tables for Testability Enhancement

In this paper we propose procedures to enhance testability by adding transitions of undefined states to state transition tables. In these procedures, transitions about undefined states, which are not described in state transition tables but exist in a synthesized gate level circuit, are added to a state transition table. Experimental results for MCNC benchmarks are shown.

A Test Method for the Static/Moving State of Targets Applied to Airport Surface Surveillance MLAT System

Due to the particularity of its location algorithm,there are some unique difficulties and features regarding the test of target motion states of multilateration(MLAT)system for airport surface surveillance.This paper proposed a test method applicable for the airport surface surveillance MLAT system,which can effectively determine whether the target is static or moving at a certain speed.Via a normalized test statistic designed in the sliding data window,the proposed method not only eliminates the impact of geometry Dilution of precision(GDOP)effectively,but also transforms the test of different motion states into the test of different probability density functions.Meanwhile,by adjusting the size of the sliding window,it can fulfill different test performance requirements.The method was developed through strict theoretical extrapolation and performance analysis,and simulations results verified its correctness and effectiveness.

Test Selection on Extended Finite State Machines with Provable Guarantees

Building high confidence regression test suites to validate new system versions is a challenging problem. A modelbased approach to build a regression test suite from a given test suite is described. The generated test suite includes every test that will traverse a change performed to produce the new version, and consists of only such tests to reduce the testing costs. Finite state machines extended with typed variables (EFSMs) are used to model systems and system changes are mapped to EFSM transition changes adding/deleting/replacing EFSM transitions and states. Tests are a sequence of input and expected output messages with concrete parameter values over the supported data types. An invariant is formulated to characterize tests whose runtime behavior can be accurately predicted by analyzing their descriptions along with the model. Incremental procedures to efficiently evaluate the invariant and to select tests for regression are developed. Overlaps among the test descriptions are exploited to extend the approach to simultaneously select multiple tests to reduce the test selection costs. Effectiveness of the approach is demonstrated by applying it to several protocols, Web services, and model programs extracted from a popular testing benchmark. Our experimental results show that the proposed approach is economical for regression test selection in all these examples. For all these examples, the proposed approach is able to identify all tests exercising changes more efficiently than brute-force symbolic evaluation.

考虑相态的垮落体材料细观参数标定方法研究——以平行黏结模型为例

基于散体力学和散体的实验室常规试验,在考虑垮落体开挖过程中煤岩颗粒呈现的多相态特征的基础上,提出结合剪切试验和颗粒柱坍塌试验的宏细观参数关系标定试验和标定方法,以颗粒流程序(particleflowcode,简称PFC)线性接触模型为例对标定试验中的各类宏细观参数关系进行了分析,并结合垮落体中救援通道开挖的相似模拟和数值模拟试验对标定方法进行了验证。结果表明:(1)剪切试验和颗粒柱坍塌试验能分别有效地反映垮落体结构在准静态流状态下的剪切破坏和垮落体在快速流状态下碰撞时的能量演变;(2)物理参数和力学参数中,摩擦系数和局部阻尼分别对处于准静态流的剪切试验和处于快速流的颗粒柱坍塌试验起主要影响作用,颗粒形态对两者的影响作用则相近且不能忽略;(3)在结合各细观参数对标定试验宏观参数的影响上,提出结合相态分析和权重分析,在确定各相态主导细观参数的基础上快速实现且满足各相态的细观参数标定;(4)采用剪切试验和颗粒柱坍塌试验标定的垮落体中救援通道开挖的数值模拟结果与相似模拟试验结果具有较高的一致性,验证了考虑相态的标定方法在垮落体研究上的可行性。

基于改进Kruskal-Wallis检验的低压开关电器状态表征参数选择

由于状态数据的多属性、高维度和大数据量,以及特征参数难以满足正态性和方差齐性检验的事实,低压开关电器的状态表征参数难于选择。针对该问题,基于非参数单体多状态样本的分组状态间秩差异性,以及特征参数Kruskal-Wallis(KW)检验统计量的计算规则和变化趋势,研究论证了单体样本特征参数表征显著性鉴别机理。同时,基于状态序列斜率变化增量和子序列变异增量,提出样本状态时序分类算法,并将该算法与参数鉴别机理相结合,形成单体多状态样本改进KW检验理论。最后,基于改进理论提出低压开关电器状态表征参数选择新方法。以交流接触器为例进行验证,结果表明该文方法适用于具有非线性、非平稳、动态随机分布等特点的低压开关电器状态表征参数选择。实例证明,基于该方法获得状态表征曲线的拟合优度可达0.91,状态划分显著性P值可达8.42848×10–266,表征与分类精度较参数选择前及同类方法提升明显,为下一步研究低压开关电器状态的精确划分与识别奠定了理论基础。

恒压下GIS固体绝缘界面气隙缺陷放电严重程度评估

为了研究GIS绝缘子界面气隙缺陷的放电发展过程,文中设计了空洞气隙缺陷模型,搭建了一套GIS气隙缺陷放电长期测试平台。基于缺陷模型的击穿电压对带有缺陷的试品施加90%Ub、60%Ub、30%Ub的交流恒压,使用UHF检测系统采集放电数据直至试品击穿。提取放电次数、放电幅值、放电时间间隔分析放电状态特征,发现GIS气隙缺陷放电发展过程存在两个阶段,前期放电幅值缓慢增大,放电脉冲逐渐稀疏,放电发展较为平稳;后期放电幅值急剧减小,放电脉冲密集,放电发展剧烈,采用k⁃means聚类算法及BP神经网络建立了气隙缺陷局放发展阶段的划分规则。研究表明,放电次数、放电幅值、放电时间间隔3种统计参量呈现阶段式单调性的趋势,可以用3种统计参量前向差分绝对值作为特征参量来评估GIS气隙放电严重程度;对GIS恒压试验进行聚类分析将放电过程划分为平稳劣化阶段和加速劣化阶段,随着外施电压水平的降低,平稳劣化阶段被压缩,加速劣化阶段占比升高。

利用原位测试试验确定黄河口潮滩粉质土固结状态研究

黄河口泥沙快速堆积在河口一带,在波浪和潮波作用下,表层沉积物处于超固结状态,但试验中发现采用Casagrande作图法求取的黄河口粉质土先期固结压力往往偏大。为了了解黄河口粉质土固结状态、合理估算先期固结压力,在黄河口刁口流路三角洲叶瓣潮坪上,现场取土在试坑内配置了模拟黄河口快速沉积形成的流体状堆积物,利用原位测试手段(静力触探、十字板剪切试验和孔隙水压力测试),并在长期观测基础上,对比研究了1.0 m深度范围内试坑和潮滩原状土体固结过程及固结状态。研究发现:黄河口快速沉积粉质土在自重作用下固结很快,固结完成后,土体强度随时间发展呈现不均匀增长,沿深度方向从上到下出现高-低-次高不均匀固结特征;历经16个月后,试坑和潮滩原状土体先期固结压力进一步提高,固结不均匀性和结构性不断增强。从试坑土体自重固结完成后的实际固结状态及原状土体物理性质指标来看,Casagrande作图法结果偏大,采用静力触探比贯入阻力法、十字板剪切试验不排水抗剪强度经验公式法估算的试坑和潮滩原状土体先期固结压力数值更为可靠;同时该方法为土体固结状态研究提供了新途径。

复杂应力条件下粗粒料的剪胀性研究进展

粗粒料的剪胀性是其强度和变形研究的重要问题之一,它取决于颗粒排列、粒间压力等细微观作用;在宏观层面,受相对密度与应力状态的影响。围绕复杂应力条件下粗粒料的剪胀问题,从粗粒料力学特性的试验研究、粗粒料的剪胀性强度准则以及临界状态与剪胀性方面,对国内外的研究进展进行了系统论述。在此基础上,提出该领域呈现如下发展态势:①通过大型真三轴试验开展粗粒料剪胀率的试验研究与理论分析,能够促进粗粒料本构理论的发展进步;②结合应力路径试验中的应力变形规律研究,可实现从常规三轴条件下向复杂应力条件下的剪胀方程的进一步发展,从而体现强度与变形问题的统一;③采用状态参量去评价土体的松密状态与剪胀性,能够耦合应力状态与孔隙比,尽量避免“一种材料,多组参数”。研究结果表明状态参量和应力路径相结合的方法,使得粗粒料的力学特性研究更加具有科学性和系统性。

基于OPT的标准化流程干预在慢性鼻窦炎伴鼻息肉手术患者中的应用

目的 探讨基于结局现状对照(outcome-present state test, OPT)模型的标准化流程干预在慢性鼻窦炎伴鼻息肉手术患者中的应用效果。方法 选取2022年9月-2023年9月于本院接受鼻内镜鼻窦手术治疗的慢性鼻窦炎伴鼻息肉患者86例为研究对象,按照入院顺序进行分组,将2022年9月-2023年2月入院的41例患者设为对照组,2023年3月-9月入院的45例患者设为观察组。对照组行常规护理干预,观察组行基于OPT模型的标准化流程干预。比较2组Lund-Kennedy鼻内镜评分、鼻腔鼻窦结局测试22条(sino-nasal outcome test-22,SNOT-22)、术后并发症发生情况。结果 术后4周,观察组Lund-Kennedy、SNOT-22评分、术后并发症发生率均低于对照组(t=2.102,P=0.039;t=2.431,P=0.017;χ2=4.174,P=0.041)。结论 基于OPT模型的标准化流程干预可提高手术效果,促进患者康复,改善患者生活质量。

美国阿拉斯加长期陆域天然气水合物试采进展及对我国的启示

随着天然气水合物勘查试采工作的不断深入,世界主要国家以实现水合物产业化开发为目标的科学理论研究和技术装备研发面临发展瓶颈,目前仅中国、日本、美国等几个国家仍在积极推进旨在突破上述发展瓶颈的长期水合物试采工作.日美两国自2014年就阿拉斯加长期陆域试采项目达成合作意向以来,基本完成了产气试验前的准备工作.本文在梳理总结已开展的中短期水合物试采项目及长期试采必要性的基础上,重点介绍了项目团队对试采场地的选择、地层测试井的钻探以及基于数据采集的目标储层表征,认为我国在缺少可供长期陆域试采的合适区域的情况下,可加强与俄罗斯在水合物勘查开发相关领域(尤其是长期陆域试采)的深入交流与合作.尽管我国的水合物试采工作在产气时长、日最高产气量和累计产气量等方面处于领先,但应针对钻井、完井、人工举升、地质力学、出砂、防砂等领域加强科学理论研究和关键技术攻关.

连云港海相软土固结状态及地质成因

软土的固结状态是分析其沉降变形的一个重要指标。为了研究连云港海相软土的固结状态,进行了多组原位十字板剪切(FVT)试验、标准固结试验和金属基索状光缆的沉降监测。结果表明:由于表层作用,导致浅部和深部软土显示出不同的固结状态,固结状态存在一个临界深度(5~6 m)。原位土抗剪强度与埋深的拟合曲线表明视超固结比(OCR_(1))大于1,但这包含了土体结构强度,不能反映土体在地质历史上曾经受过的最大有效应力,临界深度(5m)以上OCR_(1)平均值为1.74,临界深度以下OCR_1平均值为1.01,整体均为轻微超固结土。基于标准固结试验,采用塑状样试验数据计算临界深度以下软土超固结比(OCR_(2)),OCR_(2)小于1,表明其为欠固结土,在地质历史上所遭受的最大有效应力小于现在土体上覆有效应力。FVT试验得出的OCR_(1)值大于标准固结试验得出的OCR_(1),这与室内试验样的扰动和土体应力状态的改变有关,基于室内压缩试验的数据会低估OCR_(1)。基于金属基索状光缆的软土沉降监测数据在深度上的分布规律与软土OCR_(1)分布规律基本一致,OCR_(1)虽不是真正的超固结比,但这一指标直接与工程建设有关。

基于数据挖掘技术的现代电子设备运行状态辨识研究

针对当前现代电子设备运行状态辨识错误率大、耗时过程长等局限性,为了改善现代电子设备运行状态辨识正确率,设计基于数据挖掘技术的现代电子设备运行状态辨识方法。首先采集电子设备运行状态数据,采用小波变换对数据进行预处理,并提取电子设备运行状态特征,然后采用数据挖掘技术分析电子设备运行状态变化规律,建立辨识模型,最后与其它方法进行电子设备运行状态辨识对比实验。实验结果表明,所提方法的电子设备运行状态辨识正确率高,将辨识误差控制在10%以内,不仅完全可以满足现代电子设备的实际应用要求,而且辨识整体效果要优于对比方法,具有十分明显的优越性。

基于CT扫描研究颗粒形状对砂土力学性质的影响

为了探究颗粒形状对砂土力学性质的影响,选取玻璃珠、石英砂、玻璃渣3种颗粒形状差异较大的砂土作为研究对象。首先通过计算机断层(computed tomography,CT)扫描重构了3种砂土的三维结构,选取了伸长率(EI)、扁度(FI)、球度(S)3个表征颗粒形状参数的均值作为砂土颗粒整体形状参数(overall regularity,OR),并对整体形状参数OR进行统计分析。然后配制7种不同形状参数的砂土进行了常规三轴压缩试验得到了其力学强度参数,研究砂土颗粒形状对其力学强度的影响规律。结果表明:7种砂土的应力-应变曲线均为应变软化型,都呈现出先剪缩后剪胀的特性;整体形状参数OR能较好反映砂土的力学特征,即随着整体形状参数OR的减小,应变软化现象变得不明显,但其峰值偏应力呈增大的趋势;砂土的内摩擦角随整体形状参数OR的减小呈线性增长,表观黏聚力急剧增大,但最大剪胀角随OR的减小而减小。此外,将临界内摩擦角与整体形状参数OR进行线性拟合,得到了两者较好的线性关系。

济阳坳陷页岩油储层渗流特征非稳态实验

为形成一种适用于济阳坳陷页岩油储层渗流特征参数的高效而且精确的测试方法,基于一维非稳态渗流模型,建立了非稳态页岩油流动实验方法,分析不同裂缝发育情况下页岩的液测渗透率和启动压力梯度。结果表明:非稳态压力恢复法可准确测试页岩渗透率,测试时间可缩短约90%;由于气液两相间基础物性的巨大差异,液测渗透率约为气测渗透率的0.47%~2.83%;结合数值仿真和压力衰竭测试,可获得页岩液测启动压力梯度(101~102 MPa/m),其随着渗透率的增加呈幂指数递减;层理贯穿缝发育可显著降低页岩的启动压力梯度;相较于稳态法测试,非稳态压力衰竭法测试启动压力梯度数值略小。研究成果可为页岩油储层渗流参数的高效实验测试及开发方案的制定提供技术支撑。