期刊文献+
共找到607篇文章
< 1 2 31 >
每页显示 20 50 100
MULTIAXIAL CREEP-FATIGUE LIFE EVALUATION UNDER PROPORTIONAL LOADING 被引量:3
1
作者 Y.Noguchi M.Miyahara 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2004年第4期355-360,共6页
A new method was proposed for the multiaxial creep-fatigue life evaluation under proportional loadings. Because this method was derived from the strain range partitioning method with a multiaxiality factor, it was pos... A new method was proposed for the multiaxial creep-fatigue life evaluation under proportional loadings. Because this method was derived from the strain range partitioning method with a multiaxiality factor, it was possible to consider the influence of both creep-fatigue interaction and multiaxial stress state on fatigue life. In order to predict the combined axial-torsional fatigue life the damage under combined loading was defined as linear summation of the damages under axial loading and torsional loading. Axial-torsional creep-fatigue tests were carried out using tubular specimens of 316LC austenitic stainless steel and the ferritic rotor steel. This rotor steel was developed for the permanent magnet type eddy current retarder in heavy trucks. Experimentally obtained lives of both steels were well corresponded with the lives predicted by the proposed method. It was found that the proposed method was effective in multiaxial fatigue life evaluation under proportional creep-fatigue loadings. 展开更多
关键词 multiaxial fatigue creep-FATIGUE proportional loading life evaluation
下载PDF
Creep Model of High-Strength High-Performance Concrete Under Cyclic Loading 被引量:1
2
作者 李倩 LIU Muyu +1 位作者 LU Zhifang 邓晓光 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第3期622-629,共8页
Concrete creep under both static and cyclic loading conditions was investigated. Four groups of high-strength high-performance concrete (HSHPC) prism specimens were fabricated, and three of these specimens were loaded... Concrete creep under both static and cyclic loading conditions was investigated. Four groups of high-strength high-performance concrete (HSHPC) prism specimens were fabricated, and three of these specimens were loaded periodically by the MTS Landmark Fatigue Testing Machine System. Creep characteristics and creep coefficients of HSHPC under static loading and cyclic loading, respectively, were obtained and compared. The experimental results show that the creep strains under cyclic loading with a mean stress of 0.4fcp and an amplitude of 0.2fcp increase significantly compared with the creep strains under static loading, and the maximum value was 1.2-2.3 times at early stages. In addition, the creep coefficient increases nonlinearly with the number of cyclic loading repetitions. The influence coefficient for cyclic loading 1.088x(N/N0)0.078was introduced based on the previous HSHPC creep model, and then the modified creep model under cyclic loading was established. Finally, the residual method, the CEB coefficient of variation method and the B3 coefficient of variation method were applied to evaluate the modified creep model. The statistical results demonstrate that the modified creep model agrees well with the experimental measurements. Hence, it has important theoretical and practical values for accurately predicting the deflection of concrete bridges under cyclic traffic loading. 展开更多
关键词 HSHPC creep model MODIFIED CYCLIC loadING
下载PDF
Design and Performance Evaluation of a Sustained Load Dual Grip Creep Testing Machine
3
作者 Kenneth Kanayo Alaneme Bethel Jeremiah Bamike Godwin Omlenyi 《Journal of Minerals and Materials Characterization and Engineering》 2014年第6期531-538,共8页
The design and performance evaluation of a sustained load creep testing machine was undertaken in this research. The design was motivated by the need to make locally available, a cost effective, technically efficient,... The design and performance evaluation of a sustained load creep testing machine was undertaken in this research. The design was motivated by the need to make locally available, a cost effective, technically efficient, and easily operated creep testing facility;for creep behaviour studies of materials. Design drawings and purchase of materials and components for the design were undertaken after thorough evaluation of the following design and materials selection criteria: design principle and theory, local availability of raw materials and components required for the design, material properties, cost of materials and design, ease of utilization and maintenance, and basis of testing and data capture. The machine casing and frame, heating chamber (consisting of the furnace and a dual specimen mounting stage), load lever and hanger system, and the electro-technical components;were fabricated and coupled following the produced design specifications. The machine was tested and its performance was assessed using its heating efficiency, repeatability and reproducibity of experimental test results, maintainability and cost-effectiveness as criteria. It was observed from repeat tests that the machine has the capacity of generating reliable data for computing creep strain-time results. The efficiency and temperature regulating capacity of the heating unit of the machine were also observed to be very satisfactory. The cost of the design was about 112,000 Naira ($700.00) which is cheaper in comparison to similar commercial creep testing machines from abroad. The machine was also found not to pose maintenance or repairs challenges. 展开更多
关键词 creep FAILURE Analysis Machine DESIGN Strain Rate SUSTAINED load FRACTURE
下载PDF
初始加载龄期对陶粒混凝土梁徐变性能的影响
4
作者 朱红兵 金伟良 +1 位作者 李家鹏 肖宇 《混凝土》 CAS 北大核心 2024年第5期104-107,116,共5页
徐变性能对混凝土结构的承载性能有较大影响,初始加载龄期(养护龄期)对徐变有较大影响,基于4种不同初始加载龄期的陶粒混凝土梁,进行了为期200 d的徐变试验,研究初始加载龄期对陶粒混凝土梁徐变性能的影响规律试验研究,并建立基于ACI-20... 徐变性能对混凝土结构的承载性能有较大影响,初始加载龄期(养护龄期)对徐变有较大影响,基于4种不同初始加载龄期的陶粒混凝土梁,进行了为期200 d的徐变试验,研究初始加载龄期对陶粒混凝土梁徐变性能的影响规律试验研究,并建立基于ACI-209徐变计算模型和ACI-435长期挠度计算方法建立陶粒混凝土结构的徐变值计算式。结果显示:随着初始加载龄期的增加,陶粒混凝土梁的初始挠度、徐变挠度速度和最终挠度值均呈现减小的趋势,减小的幅度也随着加载龄期的延长而逐渐减弱;徐变值计算式的计算值与试验观测值较接近,所建立的计算式具有较好的准确性和适用性;综合考虑工期和经济指标,建议将90 d作为预制陶粒混凝土梁的加载龄期。研究结论可为陶粒混凝土结构徐变计算提供参考。 展开更多
关键词 陶粒混凝土梁 徐变 初始加载龄期 试验 计算模型
下载PDF
持续荷载作用下疲劳损伤混凝土梁的变形性能分析
5
作者 吴俊 张军 +3 位作者 毛江鸿 金伟良 钟小平 樊玮洁 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2024年第5期843-851,共9页
为明确往复荷载和持载作用下混凝土梁变形的发展规律,本文通过弯曲疲劳加载引入疲劳损伤后采用堆载法对4根梁进行堆载徐变试验,研究疲劳损伤对梁受压区混凝土的徐变发展规律和持续荷载作用下梁变形性能的影响。研究结果表明:相较于无损... 为明确往复荷载和持载作用下混凝土梁变形的发展规律,本文通过弯曲疲劳加载引入疲劳损伤后采用堆载法对4根梁进行堆载徐变试验,研究疲劳损伤对梁受压区混凝土的徐变发展规律和持续荷载作用下梁变形性能的影响。研究结果表明:相较于无损梁,疲劳损伤梁受拉区混凝土最大裂缝宽度、受压区混凝土总应变和总挠度更大,且在堆载作用下的发展速率更快,随着疲劳损伤程度的增大,各指标也有增大的趋势;疲劳作用促进了混凝土微裂缝的产生和发展,提前并加速了梁徐变变形的发展,导致前期疲劳加载就已产生了部分徐变应变和徐变挠度;基于试验结果建立了疲劳损伤梁受压区混凝土总徐变应变和梁徐变挠度计算模型,发现疲劳循环寿命比为0.025、0.15和0.60时的疲劳残余挠度分别相当于无损梁128、800和1180 d的徐变挠度。 展开更多
关键词 钢筋混凝土梁 持续荷载 循环荷载 疲劳损伤 徐变 徐变挠度 变形性能 混凝土裂缝
下载PDF
水稻穴盘秧苗钵体力学特性试验研究
6
作者 陈林涛 刘兆祥 +1 位作者 于新业 牟向伟 《农业工程》 2024年第2期39-47,共9页
以培杂泰丰杂交稻种为试验对象,在立体育秧温室培育穴盘秧苗。试验时苗龄28 d,钵体含水率35.76%~54.08%,仪器为TA-XT2i型质地分析仪。对穴盘苗钵体进行平板压缩、加卸载循环和蠕变试验研究,发现平板压缩变形约3.15 mm,抗压力随变形的变... 以培杂泰丰杂交稻种为试验对象,在立体育秧温室培育穴盘秧苗。试验时苗龄28 d,钵体含水率35.76%~54.08%,仪器为TA-XT2i型质地分析仪。对穴盘苗钵体进行平板压缩、加卸载循环和蠕变试验研究,发现平板压缩变形约3.15 mm,抗压力随变形的变化趋势差异明显,压缩约4 mm,抗压力出现峰值上升变化陡点。当加载力为1、2、3、4和5 N,秧苗钵体平均蠕变量0.0055、0.0055、0.0056、0.0057和0.0059 mm。试验结果表明,钵体抗压力与变形呈非线性变动;平板压缩过程,钵体无明显屈服破坏点;苗钵体面对外界加卸载时表现较强塑变能力。选用Burgers模型能有效表征穴盘苗钵体压缩蠕变特性。分析多种稻种穴盘苗力学特性,结果发现不同穴盘苗钵体抗压力与变形关系遵循非线性曲线。该研究可为水稻移栽机设计优化提供理论参考。 展开更多
关键词 水稻 钵苗 力学特性 压缩 加卸载循环 蠕变
下载PDF
注浆黏结锚杆荷载试验判稳方法的综合研究
7
作者 付文光 杨立 冯栋栋 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第4期694-704,共11页
对注浆黏结锚杆各种荷载试验的位移稳定判定方法研究表明:(1)锚固体与地层界面蠕变遵循蠕变机理,判断锚头位移稳定本质上就是判定界面蠕变是否稳定;(2)荷载较小时界面发生稳定蠕变,超过临界荷载后发生蠕变破坏,完整破坏过程可分为初始... 对注浆黏结锚杆各种荷载试验的位移稳定判定方法研究表明:(1)锚固体与地层界面蠕变遵循蠕变机理,判断锚头位移稳定本质上就是判定界面蠕变是否稳定;(2)荷载较小时界面发生稳定蠕变,超过临界荷载后发生蠕变破坏,完整破坏过程可分为初始、持续及加速3个阶段,判稳不能采用初始阶段数据、应主要依据持续阶段的蠕变特性;(3)蠕变破坏形式约2/3锚杆为突变型,1/3为缓变型,对应着3类蠕变曲线形态;(4)用于判稳的位移阈值不应小于0.1 mm,单元时长不应短于10min,位移增量不能直接用于判稳;(5)判稳应定性判断蠕变速率总体上在减速,应确定定量指标使速率维持在较低水平从而使位移收敛;(6)主要应依据具有位移与时间双重属性的参数判稳,单元时长位移增量的判稳准确度较高,而蠕变率2.0 mm任何情况下都适用;(7)以蠕变率2.0 mm为内在原则的推荐判稳方法,适用于各种应用场合及各种类型的注浆黏结锚杆,适用于各种荷载试验及快速法等试验加卸载方法。 展开更多
关键词 判稳 蠕变率 位移增量 位移阈值 稳定蠕变 蠕变破坏 蠕变机理 快速法
下载PDF
含水排土场蠕变特性及长期强度研究
8
作者 常剑 郭霁 +2 位作者 苏强 王浩然 孙鸿昌 《科技和产业》 2024年第5期280-285,共6页
为揭示排土场岩土体蠕变特性及长期强度,采用ZLB-1型三联蠕变直剪蠕变仪,以分级加载形式开展一系列试验,研究不同含水率和固结压力下,岩土体蠕变特性及长期强度变化规律。试验结果表明:15%~39.2%(饱和)含水率范围内,排土场岩土体显示为... 为揭示排土场岩土体蠕变特性及长期强度,采用ZLB-1型三联蠕变直剪蠕变仪,以分级加载形式开展一系列试验,研究不同含水率和固结压力下,岩土体蠕变特性及长期强度变化规律。试验结果表明:15%~39.2%(饱和)含水率范围内,排土场岩土体显示为非线性蠕变,且随着剪应力增加,蠕变曲线分别呈现衰减蠕变、非稳定蠕变及加速蠕变,直至试样发生破坏;施加剪应力瞬间发生较大瞬时应变,并随剪应力增加而变大;长期强度指标与含水率呈现指数递减趋势;对比15%含水率试样,饱和含水率下排土场岩土体长期强度指标中黏聚力降低66%,内摩擦角降低69%,其变化规律满足指数拟合公式。研究成果可为同类型含水排土场稳定性计算提供基础数据。 展开更多
关键词 富水排土场 分级加载 含水率 蠕变 长期强度
下载PDF
不同加卸载路径下灵敏性粉土的变形特性
9
作者 卢瑞娜 余蓉 +2 位作者 高原 石雪英 巩天真 《地下空间与工程学报》 CSCD 北大核心 2024年第2期426-436,共11页
山西汾河中游一级阶地的施工中发现,饱和粉土地基受扰动后会产生很大的附加沉降,且迟迟不能稳定,表现出灵敏性。基于一维固结蠕变试验研究不同的加卸载路径对灵敏性粉土变形特性的影响,结果表明:加卸载路径和加卸荷比是影响压缩曲线的... 山西汾河中游一级阶地的施工中发现,饱和粉土地基受扰动后会产生很大的附加沉降,且迟迟不能稳定,表现出灵敏性。基于一维固结蠕变试验研究不同的加卸载路径对灵敏性粉土变形特性的影响,结果表明:加卸载路径和加卸荷比是影响压缩曲线的重要因素;压缩曲线在出现转折时对应的应力为结构屈服应力;加荷比越大,同级荷载下沉降值、固结系数、次固结系数和主固结比都会增大,同时其压缩曲线越趋近于线性,特征转折点消失,但加荷比越大,可大大减少工期;预压荷载的大小和卸荷比都会影响灵敏性粉土的回弹量,预压荷载大于结构屈服应力时,卸荷比越大,回弹量越大,因此需要采取分级卸载方法减小回弹量,保证预压效果;目标荷载小于结构屈服应力时,超载预压法降低工后沉降效果显著。 展开更多
关键词 加卸载路径 灵敏性粉土 一维固结蠕变试验 结构屈服应力
下载PDF
煤蠕变过程电磁辐射频谱特征实验研究
10
作者 范鹏宏 聂百胜 《中国煤炭》 北大核心 2024年第7期105-114,共10页
为了研究煤在单轴蠕变加载条件下,电磁辐射频谱变化的响应规律,分别测试了不同煤种在单轴载荷下,垂直层理方向上短时蠕变过程中全阶段的电磁辐射频谱的变化特征,并讨论了其变化规律。研究结果表明,在单轴蠕变分级加载的过程中,煤体的电... 为了研究煤在单轴蠕变加载条件下,电磁辐射频谱变化的响应规律,分别测试了不同煤种在单轴载荷下,垂直层理方向上短时蠕变过程中全阶段的电磁辐射频谱的变化特征,并讨论了其变化规律。研究结果表明,在单轴蠕变分级加载的过程中,煤体的电磁辐射频率及其振幅总体趋势出现了相似的变化规律,并且各个阶段的频率及其振幅也有各自相似的变化规律。在整个蠕变过程中煤体的电磁辐射信号频率整体处在低频阶段,主要集中于0~0.5 MHz,且加速蠕变变形阶段的电磁辐射频带范围大于减速和等速蠕变变形阶段。在减速和等速蠕变变形期,煤体的电磁辐射频率的振幅变化均处在低振幅阶段;在加速蠕变变形期,可能由于煤体损伤的加剧,使得电磁辐射频率的振幅变化出现较大幅度的波动;在加速蠕变变形末期直到样品临近断裂前,煤体的电磁辐射频率的振幅值会出现增大减小增大的趋势。研究结果可为煤岩流变突变过程中损伤破坏信息的准确感知及煤岩动力灾害的智能监测与预警提供一定的实验和理论依据。 展开更多
关键词 煤岩动力灾害 单轴分级加载 短时蠕变 电磁辐射 频谱特征
下载PDF
采用“恒载零弯矩法”对大跨PC梁主梁配束的结果比较及方法优化
11
作者 张彦 赵玉川 《上海公路》 2024年第2期45-49,87,I0010,I0011,共8页
“恒载零弯矩法”是以恒载状态下的主梁弯矩为零作为目标的配束方法,在大跨PC梁桥的设计中有一定范围的应用。“恒载零弯矩”是一种目标状态,但没有具体的方法。现通过“恒载零弯矩法”与常规配束方法的对比,比较了两者的预应力钢束指... “恒载零弯矩法”是以恒载状态下的主梁弯矩为零作为目标的配束方法,在大跨PC梁桥的设计中有一定范围的应用。“恒载零弯矩”是一种目标状态,但没有具体的方法。现通过“恒载零弯矩法”与常规配束方法的对比,比较了两者的预应力钢束指标与应力、挠度等效应的区别,并在此基础上,通过分析腹板束、顶板束的力学特征,提出了优化“恒载零弯矩法”的配束方法。 展开更多
关键词 恒载零弯矩法 徐变变形 腹板束 顶板束
下载PDF
Rock bending creep and disturbance effects 被引量:1
12
作者 付志亮 郑颖人 刘元雪 《Journal of Central South University》 SCIE EI CAS 2008年第S1期438-442,共5页
The bending creep and its disturbance effects of red sandstone rock beam and oil shale rock beam were studied by adopting the self-developed gravitation level style rock creep test machine and bending creep test syste... The bending creep and its disturbance effects of red sandstone rock beam and oil shale rock beam were studied by adopting the self-developed gravitation level style rock creep test machine and bending creep test system,and the constitutive equations were established.It is found that fracture morphology of rock beams under no disturbance load is regular,cracking position of fractures is on part of loading concentration,the crack starts from a neutral plane.However,fracture morphology of rock beams under disturbance load is irregular,cracking position of fractures deviates from a neutral plane.Delayed instability of rock beam occurs for some time under constant disturbance load.When disturbance load is beyond a certain range,suddenly instability of occurs rock beam in a certain time.The results show that there is a guiding significance for creep stability in the geotechnical engineering fields. 展开更多
关键词 ROCK beam bending creep DISTURBANCE load GRAVITY DELAYED INSTABILITY
下载PDF
含钢率对长期荷载下钢管混凝土轴压性能的影响分析
13
作者 刘文华 《福建建筑》 2024年第1期129-133,共5页
为研究含钢率对长期荷载下钢管混凝土性能的影响,采用ABAQUS软件,对长期荷载作用下不同含钢率的钢管混凝土柱的变形(ε)-时间(t)、承载力(N)-时间(t)关系曲线进行计算,并在此基础上,对长期荷载作用下典型含钢率的钢管混凝土进行机理分... 为研究含钢率对长期荷载下钢管混凝土性能的影响,采用ABAQUS软件,对长期荷载作用下不同含钢率的钢管混凝土柱的变形(ε)-时间(t)、承载力(N)-时间(t)关系曲线进行计算,并在此基础上,对长期荷载作用下典型含钢率的钢管混凝土进行机理分析。分析结果表明:在长期荷载作用下,钢管混凝土构件的受力初期增长很快,随着时间的推移,大约在200 d时变形稳定,徐变趋于平稳;含钢率大则徐变小,随着含钢率的增加,钢管混凝土的徐变量减小。 展开更多
关键词 长期荷载 钢管混凝土 含钢率 徐变 机理
下载PDF
Analysis of permanent deformations of railway embankments under repeated vehicle loadings in permafrost regions 被引量:2
14
作者 Wei Ma Tuo Chen 《Research in Cold and Arid Regions》 CSCD 2015年第6期645-653,共9页
By large-scale dynamic tests carried out on a traditional sand-gravel embankment at the Beilu River section along the Qinghai-Tibet Railroad, we collected the acceleration waveforms close to the railway tracks when tr... By large-scale dynamic tests carried out on a traditional sand-gravel embankment at the Beilu River section along the Qinghai-Tibet Railroad, we collected the acceleration waveforms close to the railway tracks when trains passed. The dynamic train loading was converted into an equivalent creep stress, using an equivalent static force method. Also, the creep equation of frozen soil was introduced according to the results of frozen soil rheological triaxial tests. A coupled creep model based on a time-hardening power function rule and the Druker-Prager yield and failure criterion was estab- lished to analyze the creep effects of a plain fill embankment under repeated train loads. The temperature field of the embankment in the permafrost area was set at the current geothermal conditions. As a result, the permanent deformation of the embankment under train loading was obtained, and the permanent deformation under the train loads to the total embankment deformation was also analyzed. 展开更多
关键词 vehicle load permanent deformation creep effect permafrost regions
下载PDF
某高层结构施工阶段模拟分析
15
作者 陈明 程瀛 《广州建筑》 2024年第1期64-66,共3页
为了研究某高层结构各个施工阶段变形情况,共建立8个不同阶段的有限元模型,对其结构进行施工模拟分析。传统模拟荷载加载方式通过一次加载法得到结构变形的响应,分析计算过程较少,计算简单,得到的结果并不能反映结构实际变形特征。本文... 为了研究某高层结构各个施工阶段变形情况,共建立8个不同阶段的有限元模型,对其结构进行施工模拟分析。传统模拟荷载加载方式通过一次加载法得到结构变形的响应,分析计算过程较少,计算简单,得到的结果并不能反映结构实际变形特征。本文采取一次加载法和近似施工过程法,分别对某高层结构各个施工阶段进行施工模拟分析,结果表明:近似施工过程加载法考虑了结构找平措施,结构变形整体呈现鱼腹型规律,结构弹性收缩变形占总变形最小,收缩变形占总变形最大,相对于一次加载法更能反映结构每个施工阶段结构的变形情况,对类似工程施工模拟分析提供借鉴。 展开更多
关键词 高层结构 一次加载法 近似施工过程法 收缩徐变 施工模拟
下载PDF
大掺量粉煤灰混凝土早龄期拉伸徐变特性研究 被引量:2
16
作者 马成畅 徐斐熙 +4 位作者 杨杨 姚冀恺 倪彤元 陈春心 姚水丰 《浙江工业大学学报》 CAS 北大核心 2023年第2期131-138,共8页
为探究粉煤灰掺量和加载龄期对早龄期混凝土拉伸徐变的影响规律,在应力强度比为0.4的条件下,实验研究了不同粉煤灰掺量(0%,30%,60%)和不同加载龄期(3,7,14,28 d)下的拉伸徐变特性。研究结果表明:混凝土拉伸徐变随着加载龄期的推迟而递减... 为探究粉煤灰掺量和加载龄期对早龄期混凝土拉伸徐变的影响规律,在应力强度比为0.4的条件下,实验研究了不同粉煤灰掺量(0%,30%,60%)和不同加载龄期(3,7,14,28 d)下的拉伸徐变特性。研究结果表明:混凝土拉伸徐变随着加载龄期的推迟而递减;混凝土拉伸徐变速度在持荷初期(0~3 d)随着加载龄期的推迟呈指数规律下降,在持荷中后期(3 d后)加载龄期影响逐渐减小;在同一加载龄期,混凝土拉伸徐变随粉煤灰占比的提高而增大。拉伸徐变随强度增长呈指数规律递减,该规律在60%粉煤灰掺量的混凝土中更为显著。 展开更多
关键词 粉煤灰 混凝土 拉伸徐变 早龄期 加载龄期
下载PDF
Experimental study on creep mechanics characteristics of gassy under disturbance conditions
17
作者 付志亮 彭苏萍 +1 位作者 胡千庭 邹银辉 《Journal of Coal Science & Engineering(China)》 2008年第3期390-393,共4页
Creep mechanics characteristics of large scale tectonic coal was studied under gas draingae and disturbance conditions by using the new self-developed coal gas cou- pling three axial creep equipment.The results show t... Creep mechanics characteristics of large scale tectonic coal was studied under gas draingae and disturbance conditions by using the new self-developed coal gas cou- pling three axial creep equipment.The results show that when σ_1 is smaller,σ_3 is larger, gas pressure and disturbance load are smaller,gassy coal has no disturbance to creep. When σ_3 is smaller,gas pressure and σ_1 are larger,disturbance load is constant,gassy coal has remarkable effects of disturbance to creep.The concepts of disturbance load sensitive domain and disturbance creep sensitive domain were put forward.Under same amplitude disturbance stress condition,blasting disturbance has a stronger influence on gassy coal deformation is related to frequency of disturbance load;gas drainage,blasting excavation and mining play an important role in coal-gas outbursting.The relationship of gassy coal creep and gas pressure gradient,the creep constitutive equation built with gas pressure gradient and disturbance load as independent variables within the framework of fluid-solid two phases coupling were established. 展开更多
关键词 爆破分布 煤炭开采 含气煤层 爆破工程
下载PDF
Hot Load Deformation of Light-weight Insulating Fireclay Bricks
18
作者 HAN Bo, LI Yushan 《China's Refractories》 CAS 2012年第4期13-16,共4页
The hot load deformation tests of four kinds of insulating fireclay bricks were carried out using a high temperature creep furnace from Sinosteel Luoyang hlstitute of Refractories Reseorch Co. , Ltd. The testing load ... The hot load deformation tests of four kinds of insulating fireclay bricks were carried out using a high temperature creep furnace from Sinosteel Luoyang hlstitute of Refractories Reseorch Co. , Ltd. The testing load was fixed at 0. 069 MPa and the total testing time was with- in 6 h including the holding time of 1.5 h. The hot load defi〉rmation process of insulating fireclay bricks can be divided into three steps : ( 1 ) expansion step from room temperature to RUL Tmax;( 2 ) quick shrinkage step be- tween. RUL T and Ttest; 3 ) relatively slow shrinkage step during holding process. The deformation rate at the beginning of holding process (D0h) should be controlled withi, +0. 1%. The hot load deformation testing tem- perature of insulating fireclay bricks was optimized as the value of RUL T plus 220℃. 展开更多
关键词 insulating fireclay bricks hot load deformation refiactoriness under load creep
下载PDF
未来花园有机玻璃面板缩尺模型承载性能试验研究 被引量:2
19
作者 黄明 王综轶 +2 位作者 王元清 谢军 孙晓阳 《建筑结构》 北大核心 2023年第8期23-28,共6页
为研究江苏园博园未来花园有机玻璃面板承载性能,设计了一个有机玻璃缩尺模型,并对该模型进行了长期试验和短期试验,以考察该缩尺模型在长期荷载和短期荷载作用下的受力性能及破坏模式。结果表明,在长期荷载作用下,缩尺模型的蠕变现象... 为研究江苏园博园未来花园有机玻璃面板承载性能,设计了一个有机玻璃缩尺模型,并对该模型进行了长期试验和短期试验,以考察该缩尺模型在长期荷载和短期荷载作用下的受力性能及破坏模式。结果表明,在长期荷载作用下,缩尺模型的蠕变现象并不明显;在短期荷载作用下,该模型的极限承载力达17kN,并表现为脆性破坏;模型破坏时,试验测点处最大应力约6.9MPa,测点最大位移为104mm,说明该缩尺模型承载力较高,结构安全可靠。 展开更多
关键词 江苏园博园未来花园 有机玻璃 缩尺模型 长期加载 短期加载 蠕变 极限承载力
下载PDF
抗浮锚杆受力特性试验研究进展 被引量:2
20
作者 白晓宇 苏悦 +6 位作者 闫楠 杲晓东 于风波 李伟奇 赵文强 宋波 苑振 《科学技术与工程》 北大核心 2023年第15期6290-6302,共13页
随着基础埋深不断加大,建(构)筑物的抗浮问题愈加严重,抗浮锚杆在城市建设中得到了广泛应用。充分掌握抗浮锚杆的受力特性并厘清抗浮锚杆在长期荷载作用下力学性能的动态演化规律是保证抗浮结构安全、可靠的前提。为此,围绕抗浮锚杆的... 随着基础埋深不断加大,建(构)筑物的抗浮问题愈加严重,抗浮锚杆在城市建设中得到了广泛应用。充分掌握抗浮锚杆的受力特性并厘清抗浮锚杆在长期荷载作用下力学性能的动态演化规律是保证抗浮结构安全、可靠的前提。为此,围绕抗浮锚杆的工作原理、应力传递机制、承载特性以及蠕变性能等方面分析和评述国内外的相关研究现状。首先从抗浮锚杆的工作原理、破坏形式出发,分别对纤维增强复合材料(fiber reinforced polymer, FRP)抗浮锚杆和钢筋抗浮锚杆应力传递机制进行讨论和对比分析;从理论计算、试验研究与数值模拟三个方面对抗浮锚杆的承载特性进行阐述;进而对抗浮锚杆处于长期荷载、循环荷载作用下的蠕变性能进行归纳总结。最后梳理了抗浮锚杆在工程应用中存在的不足,同时为非金属抗浮锚杆在侵蚀环境中的服役性能提出了研究与发展方向。 展开更多
关键词 抗浮锚杆 钢筋锚杆 FRP锚杆 承载特性 蠕变
下载PDF
上一页 1 2 31 下一页 到第
使用帮助 返回顶部