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基于落锤装置的力监测压力绝对校准方法研究 被引量:7
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作者 顾廷炜 孔德仁 +1 位作者 商飞 陈静 《仪器仪表学报》 EI CAS CSCD 北大核心 2017年第3期750-756,共7页
在详细探讨了利用落锤装置进行压力校准的多种途径的基础上,针对力监测压力方法中存在的传感器力值测量精度易受预紧力和惯性力影响的问题,提出了一种改进方法,即在落锤装置原有锤头结构的基础上自行研制了高精度的应变式力传感器,推导... 在详细探讨了利用落锤装置进行压力校准的多种途径的基础上,针对力监测压力方法中存在的传感器力值测量精度易受预紧力和惯性力影响的问题,提出了一种改进方法,即在落锤装置原有锤头结构的基础上自行研制了高精度的应变式力传感器,推导了通过自研力传感器监测造压油缸内压力的惯性力修正模型,并总结了模型进一步简化所需满足的前提条件。在此基础上分别对传统和自研力传感器开展了多组校准试验,试验结果表明,采用过渡件和螺栓固定等传统安装方式会对力传感器产生附加预紧力和惯性力两方面的不良影响,造成传感器在测量锤头和活塞杆之间的撞击力时产生很大的测试误差;自研力传感器在满足重锤质量远大于活塞杆质量并保证撞击对中精度的前提下,能够直接根据传感器测得的力值和活塞杆横截面积计算出缸内的压力,和现有的比对式准静态校准方法相比,其高压段压力监测精度优于1%,可作为一种有效的压力校准方法。 展开更多
关键词 压力计量 落锤装置 力监测压力 绝对校准
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基于绝对式的压力电测系统准静态校准方法分析 被引量:1
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作者 陈静 孔德仁 +3 位作者 郭彬 陈金刚 褚俊英 项璟 《仪表技术与传感器》 CSCD 北大核心 2020年第1期104-107,共4页
压力电测法能反映压力随时间变化的全过程,数据实时性强,含有的信息量大,应用于武器系统的设计、研制及理论弹道学的分析中。国内外广泛采用的压电式压力电测系统虽然具有动态特性良好等优点,但由于其低频或零频特性比较差,因此需对电... 压力电测法能反映压力随时间变化的全过程,数据实时性强,含有的信息量大,应用于武器系统的设计、研制及理论弹道学的分析中。国内外广泛采用的压电式压力电测系统虽然具有动态特性良好等优点,但由于其低频或零频特性比较差,因此需对电测系统进行准静态校准以获取测试系统的工作特性参数等指标。文中简要介绍了准静态校准装置,即落锤液压动标装置的工作原理,阐述了绝对式准静态校准的原理,通过建立力-压力动力学理论模型,从理论上推导出力与压力之间的关系式,从而证明了力监测压力的可行性。 展开更多
关键词 压力电测系统 绝对式准静态校准 学理论模型 力监测压力
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In-situ stress measurements and stress change monitoring to monitor overburden caving behaviour and hydraulic fracture pre-conditioning 被引量:6
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作者 Puller Jesse W. Mills Ken W. +1 位作者 Jeffrey Rob G. Walker Rick J. 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第1期103-110,共8页
A coal mine in New South Wales is longwall mining 300 m wide panels at a depth of 160–180 m directly below a 16–20 m thick conglomerate strata. As part of a strategy to use hydraulic fracturing to manage potential w... A coal mine in New South Wales is longwall mining 300 m wide panels at a depth of 160–180 m directly below a 16–20 m thick conglomerate strata. As part of a strategy to use hydraulic fracturing to manage potential windblast and periodic caving hazards associated with these conglomerate strata,the in-situ stresses in the conglomerate were measured using ANZI strain cells and the overcoring method of stress relief. Changes in stress associated with abutment loading and placement of hydraulic fractures were also measured using ANZI strain cells installed from the surface and from underground. Overcore stress measurements have indicated that the vertical stress is the lowest principal stress so that hydraulic fractures placed ahead of mining form horizontally and so provide effective pre-conditioning to promote caving of the conglomerate strata. Monitoring of stress changes in the overburden strata during longwall retreat was undertaken at two different locations at the mine. The monitoring indicated stress changes were evident 150 m ahead of the longwall face and abutment loading reached a maximum increase of about7.5 MPa. The stresses ahead of mining change gradually with distance to the approaching longwall and in a direction consistent with the horizontal in-situ stresses. There was no evidence in the stress change monitoring results to indicate significant cyclical forward abutment loading ahead of the face. The forward abutment load determined from the stress change monitoring is consistent with the weight of overburden strata overhanging the goaf indicated by subsidence monitoring. 展开更多
关键词 Stress measurementOverburdenHydraulic fracturing Longwall
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Strain Monitoring and Stress Analysis of a Post-Prestressed Tunnel Liner 被引量:2
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作者 亢景付 王金辉 《Transactions of Tianjin University》 EI CAS 2006年第3期215-221,共7页
The strain monitoring and stress analysis of a new type of post-prestressed tunnel liner were carried out. The instrumentation block of the tunnel liner, with the dimensions of 12.06 m in length, 6 500 mm in diameter,... The strain monitoring and stress analysis of a new type of post-prestressed tunnel liner were carried out. The instrumentation block of the tunnel liner, with the dimensions of 12.06 m in length, 6 500 mm in diameter, and 650 mm in thickness, was post-prestressed with the unbonded tendons, each of which consists of 8 pieces of double-looped strands and the axial spacing of the tendons is 500 mm. Concrete strain meters, rebar meters, load cell and zero-stress meters were installed for the strain monitoring. The tensioning loads were applied incrementally in three cycles (50%, 77% and 100%) at the concrete age of 28 d and the tensioning work lasted for 187.1 h. Strain readings were taken before and after each cycle during tensioning period and at the specified time interval after tensioning period. It is found that concrete creep developed over tensioning period is 30% of total strain and 41.5% of elastic strain respectively. Prestress force in the unbonded tendon and concrete stress in the liner were evaluated according to the observed strain variations. Both of them are time-dependent, and about 5.3%, 8.3% and 9.0% of the prestress losses are observed at the age of 1 d, 30 d and 60 d respectively after stressing. The distribution of prestress in the liner is relatively uniform and meets the design requirement. 展开更多
关键词 hydraulic structure concrete creep tensioning period instrumentation elastic stress
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PLASTIC LIMIT ANALYSIS OF DISCONTINUOUS LINING UNDERGROUND PRESSURE
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作者 尤春安 《Journal of Coal Science & Engineering(China)》 1999年第1期50-55,共6页
Discontinuous lining is a special form of support in underground excavation. Based on the method of plastic limit analysis, it is found the upper and the lower bound solution of the pressure of circular discontinuous ... Discontinuous lining is a special form of support in underground excavation. Based on the method of plastic limit analysis, it is found the upper and the lower bound solution of the pressure of circular discontinuous lining and discussed support parameter of discontinuous lining and its applicable conditions , which provides theoretical basis for the design and calculation of discontinuous lining. 展开更多
关键词 discontinuous lining plastic limit analysis the upper and the lower bound theorem
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Online Monitoring the Products Quality by Measuring Cavity Pressure during Injection Molding
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作者 Chung-Ching Huang Chung-Da Lin +4 位作者 Yi-Jen Yang His-Jung Chang Jui-Wen Chang Chih-Husiung Chung Shen-Houng Chen 《Journal of Mechanics Engineering and Automation》 2012年第11期682-687,共6页
Injection molding is a complicated production technique for the manufacturing of polymer products. During injection molding, it's hard to predict molding quality; the injection molding parameters, such as mold temper... Injection molding is a complicated production technique for the manufacturing of polymer products. During injection molding, it's hard to predict molding quality; the injection molding parameters, such as mold temperature, melt temperature, packing pressure and packing time, affect the final properties of product. The cavity pressure is a significant key factor. Residual stress and injection molding weight are significantly affected by the cavity pressure. This study created an approach to predict weight of injection-molded by real-time online cavity pressure monitoring. This study uses a 6-inch with thickness lmm light guide panel and the largest area beneath the pressure curve of time as well as the maximum pressure as its characteristic. The upper and lower limits of the control are set to +2 standard deviations, and GUI (Graphical User Interface)-based LabVIEW software is used to perform calculation and analysis of the pressure curve. The results of the experiment show that the online internal cavity pressure monitoring system can effectively monitor the quality of the molded products. In 500 injection molding cycle tests, its error rate was less than 8%, whereas the deviation in mass of the molded products selected through the system's filtering process was successfully controlled to be within ±4%. 展开更多
关键词 Injection molding internal cavity pressure online monitoring quality determination
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