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声学综合无损检测技术

陈积懋

《中国工程科学》 2000年 第2卷 第4期   页码 64-69

摘要:

论述了检测复合材料和胶接结构不连续(缺陷)的新型多模综合无损检测技术。该技术以声与超声检测技术为基础,包含五种不同检测模式,用以检测复合材料与胶接结构的失粘、脱粘、分层、疏松、夹芯压皱及其他缺陷。它适用于复合材料与构件的制造、维修和使用现场。它的适用对象范围广泛,几乎覆盖了现有常用的复合材料和胶接结构。它的检测可靠性高,重复精度好。文章还讨论了组成多膜声学综合胶接检测仪的五种不同检测模式的原理,并从我们和国内外同行的大量实践经验出发,说明了综合无损检测技术的巨大发展前景。

关键词: 声学综合检测     综合无损检测     复合材料无损检测     机械阻抗分析     振动分析     共振检测    

超轻折叠夹层圆柱壳的制备及力学性能测试 Article

李万欣, 郑青, 范华林, 冀宾

《工程(英文)》 2020年 第6卷 第2期   页码 196-204 doi: 10.1016/j.eng.2019.11.008

摘要:

在本研究中,我们设计、制备和测试了两种新型折叠夹层圆柱壳。格栅夹芯具有周期性的“之”字形波纹,其脊线与谷线沿着轴向或环向延伸。通过自由振动和轴向压缩试验,我们研究了圆柱壳的固有频率、自由振动模态、承载能力和失效模式。通过减小局部蒙皮周期单元的尺寸,折叠格栅夹芯能有效地抑制折叠夹层圆柱壳的局部屈曲;通过提高夹层的剪切刚度,折叠格栅夹芯能有效地提高折叠夹层圆柱壳整体的抗屈曲性能。圆柱壳在材料失效模式下失效,其具有良好的承载能力。轴向折叠夹层圆柱壳具有更高的承载能力,而环向折叠夹层圆柱壳具有更高的固有频率。这两种折叠格栅内芯为工程师设计有强度或振动要求的夹层圆柱壳提供了一种选择。本研究也为大尺寸折叠结构的制作和工程应用提供了一种可行的方法。

关键词: 折叠夹层圆柱壳     制备     力学试验    

机电装备的失效分析、安全评定和无损检测

钟群鹏,武淮生,张峥,田永江

《中国工程科学》 1999年 第1卷 第1期   页码 43-48

摘要:

从认识论的高度阐明失效、失效分析和预防在人类科学技术发展中的属性、地位和作用。失效分析和预防具有多学科交叉综合的属性,它的发展依赖于应用学科、应用基础学科、甚至于基础学科的发展,但又对它们的发展起重要反转作用和影响。因此,它是科学技术第一生产力中最积极、最活跃的因素之一。从方法论的角度进一步叙述了失效分析与失效预防之间的辩证关系。失效分析是一种事后的逆向思维过程,它是从异常现象(结果)到因素(模式、原因和机理)的反向科技探索,而失效预防(安全评定)则是从因素到结果的一种事先的正向思维过程。逆向思维与正向思维协同并用,事后分析转化为事先分析,构成科学技术研究活动和科技发展的全过程,两者不可偏废。综述了失效分析和失效预防(安全评定)的主要内容、技术、方法和它们的发展趋势,并提出它们与无损检测技术之间的关系。

关键词: 机电装备     失效分析     安全评定     无损检测    

Effect of wood dust type on mechanical properties, wear behavior, biodegradability, and resistance to

Sawan KUMAR, Ajitanshu VEDRTNAM, S. J. PAWAR

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1446-1462 doi: 10.1007/s11709-019-0568-9

摘要: The present work reports the inclusion of different proportions of Mango/Sheesham/Mahogany/Babool dust to polypropylene for improving mechanical, wear behavior and biodegradability of wood-plastic composite (WPC). The wood dust (10%, 15%, 20% by weight) was mixed with polypropylene granules and WPCs were prepared using an injection molding technique. The mechanical, wear, and morphological characterizations of fabricated WPCs were carried out using standard ASTM methods, pin on disk apparatus, and scanning electron microscopy (SEM), respectively. Further, the biodegradability and resistance to natural weathering of WPCs were evaluated following ASTM D5338-11 and ASTM D1435-99, respectively. The WPCs consisting of Babool and Sheesham dust were having superior mechanical properties whereas the WPCs consisting of Mango and Mahogany were more wear resistant. It was found that increasing wood powder proportion results in higher Young’s modulus, lesser wear rate, and decreased stress at break. The WPCs made of Sheesham dust were least biodegradable. It was noticed that the biodegradability corresponds with resistance to natural weathering; more biodegradable WPCs were having the lesser resistance to natural weathering.

关键词: wood-plastic composites     mechanical testing     wear     biodegradability     injection molding     weathering    

Progress in terahertz nondestructive testing: A review

Shuncong ZHONG

《机械工程前沿(英文)》 2019年 第14卷 第3期   页码 273-281 doi: 10.1007/s11465-018-0495-9

摘要: Terahertz (THz) waves, whose frequencies range between microwave and infrared, are part of the electromagnetic spectrum. A gap exists in THz literature because investigating THz waves is difficult due to the weak characteristics of the waves and the lack of suitable THz sources and detectors. Recently, THz nondestructive testing (NDT) technology has become an interesting topic. This review outlines several typical THz devices and systems and engineering applications of THz NDT techniques in composite materials, thermal barrier coatings, car paint films, marine protective coatings, and pharmaceutical tablet coatings. THz imaging has higher resolution but lower penetration than ultrasound imaging. This review presents the significance and advantages provided by the emerging THz NDT technique.

关键词: terahertz pulsed imaging (TPI)     nondestructive testing (NDT)     composite material     thermal barrier coating    

Novel sensing techniques for full-scale testing of civil structures

Kaoshan DAI, Zhenhua HUANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 240-256 doi: 10.1007/s11709-012-0172-8

摘要: Performing full-scale structural testing is an important methodology for researchers and engineers in the civil engineering industry. Full scale testing helps the researchers understand civil infrastructures’ loading scenarios, behaviors, and health conditions. It helps the engineers verify, polish, and simplify the structural design and analysis theories. To conduct a full-scale structural testing, sensors are used for data acquisitions. To help structural researchers and engineers get familiar with sensing technologies and select the most effective sensors, this study reviewed and categorized new sensing techniques for full-scale structural testing applications. The researchers of this study categorized sensors used for civil-infrastructure testing into traditional contact sensors and remote sensors based upon their application methodologies, and into cabled sensors and wireless sensors based upon their data communication strategies. The detailed descriptions of wireless sensors and remote sensing techniques and their on-site full-scale applications are presented.

关键词: sensing technique     full-scale testing     wireless sensor     remote sensing     LiDAR     laser vibrometer    

Permeability testing of drilling core sample from pavement

WANG Suda, TANG Zhengguang, NING Xiaojun, WU Peiguan, XING Pingyi

《结构与土木工程前沿(英文)》 2008年 第2卷 第4期   页码 391-394 doi: 10.1007/s11709-008-0045-3

摘要: The permeability coefficient of pavement material is a very important parameter in designing the drainage of pavement structures and is also used to evaluate the quality of road construction. New equipment is used to measure the permeability coefficient of the pavement drilling core sample and relevant testing methods are introduced. Testing drilling core samples from a certain highway of Yunnan province has been proven to be feasible. The test results are also analyzed.

关键词: province     material     feasible     permeability coefficient     equipment    

Shaking table testing of hard layered soil-pile-structure interaction system

LI Peizhen, REN Hongmei, LU Xilin, SONG Heping, CHEN Yueqing

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 346-352 doi: 10.1007/s11709-007-0046-7

摘要: Shaking table tests on a dynamic interaction system of hard layered soil, pile foundation and frame structure were carried out. The earthquake damage of the superstructure and foundation was reproduced. Based on these tests, several key issues about the seismic response of the dynamic soil-structure interaction (SSI) system were studied. The natural frequency of the system was less than that of the structure on rigid foundation if the SSI is not taken into account, while its damping ratio was larger than that of the structure. The mode shape of the system was different from that of the structure on the fixed base in that there were rocking and swinging at the foundation. Magnification or reduction of vibration transferred by soil was related to soil characteristic, excitation magnitude, and so on. Generally, sand magnifies vibration, while viscous powder soil dampens vibration. The components of the acceleration response at the top of the superstructure were based on the relative magnitude of the rocking stiffness, the swing stiffness of the foundation and the stiffness of the super-structure. The multi-direction excitations have little effect on the key issues of the horizontal SSI.

关键词: super-structure     Generally     Magnification     frequency     different    

Experimental monitoring of the strengthening construction of a segmental box girder bridge and field testing

Ali Fadhil NASER, Zonglin WANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 308-320 doi: 10.1007/s11709-012-0140-3

摘要: Prestressed concrete segmental box girder bridges are composed of short concrete segments that are either precast or cast in situ and then joined together by longitudinally post-tensioning internal, external, or mixed tendons. The objectives of this study are to monitor the construction process of the external prestressing tendons to strengthen the bridge structure and perform a field load test to measure the strain and the deflection of the anchorage devices of the external prestressing tendons to determine the state of these devices after tension forces are applied. The monitoring process of the external prestressing tendons construction includes inspecting the cracks in the diaphragm anchorage and the deviation block devices before the tension forces are applied to the external tendons; measuring the deformation of the steel deviation cross beam during the tension process; measuring the deformation of the box girder after different levels of tension forces are applied; measuring the elongation of the external tendons in each level of the tension; and measuring the natural frequency of the external tendons after the tension process is complete. The results of the monitoring process show that the measured values of the deformation, the elongation, and the natural frequency meet the requirements. Therefore, there is no damage during the construction and the tensioning of the external prestressing tendons. A field load test is performed to the anchorage beam, the steel deviation block devices, and the steel deviation cross beam. The field load test results of the anchorage devices show that the values of the strains, the stresses, and the deflection are less than the respective allowable limit values in the requirements. Therefore, the anchorage devices have sufficient strength, and the working state is good after the tension forces are applied to the external prestressing tendons.

关键词: prestressed concrete     box girder     monitoring     external tendons     strain     deflection    

Sulfidation/regeneration multicycle testing of nickel-modified ZnFe

Wei LI, Jinju GUO, Jiejie HUANG, Jiaotao ZHAO

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 435-440 doi: 10.1007/s11705-010-0506-9

摘要: A commercial metal oxide sorbent for the desulphurization of coal-derived gas requires high desulphurization reactivity, mechanical strength, ability to regenerate, and stability to endure many sulfidation-regeneration cycles. In this paper, the sulfur capacity and multiple cycles of a nickel-modified ZnFe O sorbent prepared by the sol-gel auto-combustion method were measured in a fixed-bed reactor at middle temperature of 300°C (sulfidation temperature) and 500°C (regeneration temperature). Also, the BET surface area, pore volume, average pore diameter and X-ray diffraction (XRD) patterns of the sorbent through multicycles were studied. Multicycle runs indicate that the sulfidation reactivity decreases slightly during the second cycle and keeps steady in the following cycles. The results indicate that the nickel-modified ZnFe O keeps high reactivity and structural stability in the multicycle testing of sulfidation/regeneration.

关键词: hot gas desulphurization     nickel-modified ZnFe2O4     sulfidation/regeneration    

Steam turbine governor modeling and parameters testing for power system simulation

Ying LI, Chufeng PENG, Zenghui YANG

《能源前沿(英文)》 2009年 第3卷 第2期   页码 198-203 doi: 10.1007/s11708-009-0004-2

摘要: The theoretical modeling, parameters test and model correction for a steam turbine (ST) governor are discussed. A set of ST Governor system model for power system simulation is created based on this research. A power system simulation for an actual power grid accident is conducted using this new model and the comparison between the simulation and actual data show that the results are satisfactory.

关键词: power system simulation     ST governor system     modeling     parameters testing    

Vibration testing of a steel girder bridge using cabled and wireless sensors

Dapeng ZHU, Yang WANG, James BROWNJOHN

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 249-258 doi: 10.1007/s11709-011-0113-y

摘要: Being able to significantly reduce system installation time and cost, wireless sensing technology has attracted much interest in the structural health monitoring (SHM) community. This paper reports the field application of a wireless sensing system on a 4-span highway bridge located in Wayne, New Jersey in the US. Bridge vibration due to traffic and ambient excitation is measured. To enhance the signal-to-noise ratio, a low-noise high-gain signal conditioning module is developed for the wireless sensing system. Nineteen wireless and nineteen cabled accelerometers are first installed along the sidewalk of two neighboring bridge spans. The performance of the wireless sensing system is compared with the high-precision cabled sensing system. In the next series of testing, 16 wireless accelerometers are installed under the deck of another bridge span, forming a 4 × 4 array. Operating deflection analysis is successfully conducted using the wireless measurement of traffic and ambient vibrations.

关键词: wireless sensing     structural health monitoring (SHM)     signal conditioning     operating deflection analysis     ambient vibration    

SOFC单电池测试方法

屠恒勇

《中国工程科学》 2013年 第15卷 第2期   页码 33-38

摘要:

固体氧化物燃料电池(SOFC)性能的测试结果能揭示材料和制备方法及其性能之间的复杂关系,确定燃料电池内部损耗的各种来源,并指导有关材料和制备技术的研发。在SOFC进入商业化发展的前期,测试方法的标准化有助于建立基础研究和开发研究间的有效和可靠联系,实现各研究机构所得测试结果的可比性,从而推动基础研究成果转化为现实的生产力。本文综述了国际上有关单电池标准测试系统的建立和步骤的制定以及测试结果报告的标准化,指出了在我国建立完善的SOFC发电技术标准体系的重要性和迫切性。

关键词: 固体氧化物燃料电池     性能测试     测试步骤     标准化    

A bionic approach for the mechanical and electrical decoupling of an MEMS capacitive sensor in ultralow

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-023-0747-1

摘要: Capacitive sensors are efficient tools for biophysical force measurement, which is essential for the exploration of cellular behavior. However, attention has been rarely given on the influences of external mechanical and internal electrical interferences on capacitive sensors. In this work, a bionic swallow structure design norm was developed for mechanical decoupling, and the influences of structural parameters on mechanical behavior were fully analyzed and optimized. A bionic feather comb distribution strategy and a portable readout circuit were proposed for eliminating electrostatic interferences. Electrostatic instability was evaluated, and electrostatic decoupling performance was verified on the basis of a novel measurement method utilizing four complementary comb arrays and application-specific integrated circuit readouts. An electrostatic pulling experiment showed that the bionic swallow structure hardly moved by 0.770 nm, and the measurement error was less than 0.009% for the area-variant sensor and 1.118% for the gap-variant sensor, which can be easily compensated in readouts. The proposed sensor also exhibited high resistance against electrostatic rotation, and the resulting measurement error dropped below 0.751%. The rotation interferences were less than 0.330 nm and (1.829 × 10−7)°, which were 35 times smaller than those of the traditional differential one. Based on the proposed bionic decoupling method, the fabricated sensor exhibited overwhelming capacitive sensitivity values of 7.078 and 1.473 pF/µm for gap-variant and area-variant devices, respectively, which were the highest among the current devices. High immunity to mechanical disturbances was maintained simultaneously, i.e., less than 0.369% and 0.058% of the sensor outputs for the gap-variant and area-variant devices, respectively, indicating its great performance improvements over existing devices and feasibility in ultralow biomedical force measurement.

关键词: micro-electro-mechanical system capacitive sensor     bionics     operation instability     mechanical and electrical decoupling     biomedical force measurement    

Field testing of geosynthetic-reinforced and column-supported earth platforms constructed on soft soil

Qiangong CHENG,Jiujiang WU,Dongxue ZHANG,Fengping MA

《结构与土木工程前沿(英文)》 2014年 第8卷 第2期   页码 124-139 doi: 10.1007/s11709-014-0255-9

摘要: This paper is focused on the behavior of geosynthetic-reinforced and column-supported (GRCS) earth platforms in soft soil. By analyzing the data of a 15-month long field monitoring project, the bearing behavior and effectiveness of GRCS earth platforms are discussed in detail. It can be found that the soil arching is generated when the filling reaches a certain height. The measured pressure acting on the soil in the center of four piles was smaller than that acting on the soil between two piles. The elongation and the tension of the geogrid located in the soil between piles are both larger than the corresponding values on the pile top. The skin friction of piles is relatively small in the soil layer with low strength and the load transfer of the axial force in those layers is significant; meanwhile, the opposite situation occurs in the soil layer with high strength. The pore water pressure at shallow locations increases slightly with the filling height and is greatly affected by the increasing filling load. The layered settlement is directly proportional to the filling height, and the corresponding amount is relevant to the locations and the properties of specific soil layers. Additionally, the lateral displacement of the embankment increases with greater loading and decreases with increased depth. These suggest that the use of GRCS system can reduce lateral displacements and enhance the stability of an embankment significantly.

关键词: geosynthetic-reinforced and column-supported (GRCS) earth platforms     soft soil     bearing behavior     settlement and deformation     field testing    

标题 作者 时间 类型 操作

声学综合无损检测技术

陈积懋

期刊论文

超轻折叠夹层圆柱壳的制备及力学性能测试

李万欣, 郑青, 范华林, 冀宾

期刊论文

机电装备的失效分析、安全评定和无损检测

钟群鹏,武淮生,张峥,田永江

期刊论文

Effect of wood dust type on mechanical properties, wear behavior, biodegradability, and resistance to

Sawan KUMAR, Ajitanshu VEDRTNAM, S. J. PAWAR

期刊论文

Progress in terahertz nondestructive testing: A review

Shuncong ZHONG

期刊论文

Novel sensing techniques for full-scale testing of civil structures

Kaoshan DAI, Zhenhua HUANG

期刊论文

Permeability testing of drilling core sample from pavement

WANG Suda, TANG Zhengguang, NING Xiaojun, WU Peiguan, XING Pingyi

期刊论文

Shaking table testing of hard layered soil-pile-structure interaction system

LI Peizhen, REN Hongmei, LU Xilin, SONG Heping, CHEN Yueqing

期刊论文

Experimental monitoring of the strengthening construction of a segmental box girder bridge and field testing

Ali Fadhil NASER, Zonglin WANG

期刊论文

Sulfidation/regeneration multicycle testing of nickel-modified ZnFe

Wei LI, Jinju GUO, Jiejie HUANG, Jiaotao ZHAO

期刊论文

Steam turbine governor modeling and parameters testing for power system simulation

Ying LI, Chufeng PENG, Zenghui YANG

期刊论文

Vibration testing of a steel girder bridge using cabled and wireless sensors

Dapeng ZHU, Yang WANG, James BROWNJOHN

期刊论文

SOFC单电池测试方法

屠恒勇

期刊论文

A bionic approach for the mechanical and electrical decoupling of an MEMS capacitive sensor in ultralow

期刊论文

Field testing of geosynthetic-reinforced and column-supported earth platforms constructed on soft soil

Qiangong CHENG,Jiujiang WU,Dongxue ZHANG,Fengping MA

期刊论文