Mechanical Performance and Stress-Strain Relationships for Grouted Splices Under Tensile and Cyclic Loadings

Lin, Feng,Wu, Xiaobao Korea Concrete Institute 2016 International Journal of Concrete Structures and M Vol.10 No.4

Experimental studies were conducted on 36 grouted splices to investigate their mechanical performance under four loading schemes: (1) incremental tensile loading, (2) repeated tensile loading, (3) cyclic loading at high stress, and (4) cyclic loading at large strain. Load-deformation responses of the grouted splices under cyclic loadings were featured with pinching effect and stiffness degradation compared to those responses under tensile loadings. The shape of the hysteresis loops of load-deformation curves was similar to that under incremental tensile loading. For the purpose of structural analysis, stress-strain relationships were presented for grouted splices under various loadings.

A New Segmentation-based Animation Storage Format On Mobile Platform

Lin Feng,Ziqiang Diao,Yu Cai,Yunzhe Sun 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-

Handheld computers such as mobile phone are becoming new platform for gaming. However, the limited memory is the main bottleneck that affects the game development. A new segmentation-based animation storage format is proposed to partly solve such problem. The key unit is extracted from segmented image and then can be reused in different key frames so that the size of the animation file can be greatly reduced. Furthermore, a convenient interface for data manipulation is also proposed, which can improve efficiency during development.

The Research of the PNG Image Encryption Algorithm on the Mobile Platform

Lin Feng,Lizhu Wang,Tao Sun,Yuzhe Sun 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-

This article has thoroughly researched how to store the images used in the game development on the mobile platform, and proposed a new algorithm for both encryption and compression. While encrypting, the algorithm performs double encryption method, the self-encryption of the encrypted key is also used and the encrypted key is got according to the decryption seed and the system seed. The method is very simple that only addition and subtraction etc. operations are needed and meanwhile it is has several advantages: diversities of encryption technologies are used, the decryption process is fast, there is no high demand of the hardware performance and all the images are integrated into a single file to compress them. In the applications, the algorithm is both secure and efficient because it is robust against being decompiled and it has a cheerful compression rate.

Effects of geometrical parameters of an oil-water separator on the oil-recovery rate

Linfeng Piao,김나영,박형민 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

As the economical and environmental damages due to the accidental oil-spills in marine environment increase gradually, more activecountermeasure needs to be developed. In this respect, in the present study, we propose a new design of oil-water separation system andinvestigate the effects of several geometrical features on the oil-recovery rate, based on a two-dimensional numerical simulation. Theworking mechanism of current separator is to utilize the density difference between the oil and water, which is strengthened by addingmomentum to the oil-water mixture flow through a “U-shaped” passage. Along the flow passage, we locate additional parts such as baffleplate, weir plate, and water outlet. While optimizing the conditions of these to maximize the oil recovery, it is found that the formationand stable retention of water layer between the water outlet and weir plate is critical to separate and store the above-layered oil. Finally,these findings are further confirmed with a basic experimental test with a three-dimensional oil-water separator model.

Cyclic response and design procedure of a weak-axis cover-plate moment connection

Linfeng Lu,Yinglu Xu,Huixiao Zheng,James B.P. Lim 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.3

This paper systematically investigated the mechanical performance of the weak-axis cover-plate connection, including a beam end monotonic loading test and a column top cyclic loading test, and a series of parametric studies for exterior and interior joints under cyclic loading using a nonlinear finite element analysis program ABAQUS, focusing on the influences of the shape of top cover-plate, the length and thickness of the cover-plate, the thickness of the skin plate, and the steel material grade. Results showed that the strains at both edges of the beam flange were greater than the middle's, thus it is necessary to take some technical methods to ensure the construction quality of the beam flange groove weld. The plastic rotation of the exterior joint can satisfy the requirement of FEMA-267 (1995) of 0.03 rad, while only one side connection of interior joint satisfied ANSI/AISC 341-10 under the column top cyclic loading. Changing the shape or the thickness or the length of the cover-plate did not significantly affect the mechanical behaviors of frame joints no matter in exterior joints or interior joints. The length and thickness of the cover-plate recommended by FEMA 267 (1995) is also suitable to the weak-axis cover-plate joint. The minimum skin plate thickness and a design procedure for the weak-axis cover-plate connections were proposed finally.

Decoupling Control of 2-link Manipulator with Model Following Control and Proposed Control Gains Design (ICCAS 2012)

Linfeng Lan,Kousuke Okabe,Ryuichi Oguro,Hideki Honda 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

In this paper, a new decoupling control scheme of 2-link industrial manipulator with application of the model following control has been proposed. Compensation torque used for removing interference force between two arms of the manipulator has been designed in feed-forward control loop. Compared with the conventional scheme, the proposed scheme is more simple and realistic to be taken in to practice for general purpose controllers. And, a new design consideration for control gains has also been shown. Moreover, disturbance observer is applied to cope with model error problem in feed-back control loop. Effectiveness of the proposed decoupling control scheme has been confirmed through simulation results.

Efficient and specific gene knockdown by small interfering RNAs for biomedical application

Linfeng Huang 한국실험동물학회 2019 한국실험동물학회 학술발표대회 논문집 Vol.2019 No.7

Study on three-dimensional elastic deformation characteristics of flexspline in harmonic drive based on Rayleigh-Ritz method with accelerated convergence strategy

Linfeng Qiu,Manyi Chen,Gang Song 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

The 3D deformation mechanism of flexspline (FS) is the foundation of harmonic drive. In this paper, a novel methodology based on Rayleigh-Ritz method (RRM) is proposed to solve the three-dimensional elastic deformation of FS. First, the analytical model of RRM for 3D elastic deformation is formulated. A three-dimensional displacement trial function is designed according to the structure and constraints of FS. The RRM improves the accuracy of the solution by increasing the number of terms of the trial function. According to the completeness of the trial function, the real elastic deformation state can be approached arbitrarily in theory. The convergence efficiency of the actual iteration process is greatly affected by the iteration strategy. Therefore , an accelerated convergence strategy is proposed to overcome the drawback of poor convergence rate in the general iterative process. The elastic deformation characteristics of FS are studied by the new method, and a sensitivity analysis of structural parameters is performed. The results demonstrate that the new method is highly accurate and efficient. The radial deflection is slightly arch-shaped along the axial direction, reaching the maximum value near the axial position of the displacement constraint. The tangential deflection is 0 on the symmetry plane, and the value is smaller when it is farther away from the symmetry plane, which reflects the tendency of the gear tooth deflecting towards the major shaft section of the wave generator. The descending order of sensitivity of structural parameters affecting taper deformation is cylinder length (Pl), radii difference (Pd), cylinder thickness (Pt), hole radius (Ph), fillet radius (Pf) and gear rim width (Pw). The descending order of sensitivity of structural parameters affecting tooth skewness is Pl, Pd, Ph, Pf, Pw and Pt.

Cyclic performance and design recommendations of a novel weak-axis reduced beam section connection

Linfeng Lu,Yinglu Xu,Jie Liu,James B.P. Lim 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.3

In previous weak-axis moment connection tests, brittle fracture always initiated near the edge of the beam flange groove weld due to force flow towards the stiffer column flanges, which is the opposite pattern as strong-axis moment connections. As part of the China NSFC (51278061) study, this paper tested two full-scale novel weak-axis reduced beam section moment connections, including one exterior frame connection specimen SJ-1 under beam end monotonic loading and one interior frame joint specimen SJ-2 under column top cyclic loading. Test results showed that these two specimens were able to satisfy the demands of FEMA-267 (1995) or ANSI/AISC 341-10 (2010) without experiencing brittle fracture. A parametric analysis using the finite element software ABAQUS was carried out to better understand the cyclic performance of the novel weak-axis reduced beam section moment connections, and the influence of the distance between skin plate and reduced beam section, <i>a</i>, the length of the reduced beam section, <i>b</i>, and the cutting depth of the reduced beam section, <i>c</i>, on the cyclic performance was analyzed. It was found that increasing three parametric values reasonably is beneficial to forming beam plastic hinges, and increasing the parameter <i>a</i> is conducive to reducing stress concentration of beam flange groove welds while increasing the parameters <i>b</i> and <i>c</i> can only reduce the peak stress of beam flange groove welds. The rules recommended by FEMA350 (2000) are suitable for designing the proposed weak-axis RBS moment connection, and a proven calculation formulation is given to determine the thickness of skin plate, the key components in the proposed weak-axis connections. Based on the experimental and numerical results, a design procedure for the proposed weak-axis RBS moment connections was developed.

Fault feature extraction of a rotor system based on local mean decomposition and Teager energy kurtosis

Linfeng Deng,Rongzhen Zhao 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4

Feature extraction is the most important step for machine fault diagnosis, but useful features are very difficult to extract from the vibrationsignals, especially for intelligent fault diagnosis based on data-driven technique. An integral method for fault feature extraction basedon local mean decomposition (LMD) and Teager energy kurtosis (TEK) is proposed in this paper. The raw vibration signals are firstprocessed via LMD to produce a group of product functions (PFs). Then, the Teager energies are computed using the derived PFs. Subsequently,each Teager energy data set is directly used to calculate the corresponding TEK. A vibration experiment was performed on arotor-bearing rig with rub-impact fault to validate the proposed method. The experimental results show that the proposed method canextract different TEKs from the mechanical vibration signals under two different operating conditions. These TEKs can be employed toidentify the normal and rub-impact fault conditions and construct a numerical-valued machine fault decision table, which proves that thismethod is suitable for fault feature extraction of the rotor-bearing system.