Oil Debris Signals Enhancement Based On Wavelet Analysis for Wind Turbine Condition Monitoring

Shenggang Yang,Xiaoli Li,Ming Liang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.10

Oil debris signals are applied to monitor lubricant oil conditions and fault diagnosis of a wind turbine. However, the signals will be influenced by the vibration of transmission mechanism and background noise, hence false alarms and undetected particles will limit sensors ability in examining fine particles in oil debris. This paper presents an approach to enhance the performance of oil debris signals. The de-noising of signals used a wavelet filtering to remove the vibration of a wind turbine, and then set a threshold to remove the background noise which caused by the system of measurement. The effectiveness of this enhanced measurement system is tested by using simulated and experimental signals.

Research on Local Buckling of Stainless Steel Lipped C-Section Beam Around Strong-Axis

Shenggang Fan,Hang Zhou,Zhixia Ding,Chenxu Li,Qinglin Jiang 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.5

To study the local buckling capacity of stainless steel beams with lipped C-sections under strong axis bending, tensile tests were performed on 12 stainless steel coupons based on S30408 austenitic stainless steel (AISI304) in fl at and corner areas, and mechanical properties and stress–strain curves were obtained. Then, local buckling capacity tests were performed on 6 specimens of stainless steel beams under strong axis bending to determine their mechanical properties and failure mechanism. The failure phenomenon, load–displacement curve, load–strain curve and local buckling capacity were determined. Results show that the failure modes of the specimens are local buckling failure of the fl ange and web at mid-span. Additionally, a refi ned fi nite element analysis model was developed using Python and ABAQUS to simulate and analyse the mechanical performance and local buckling capacity. Then, the analytical results were compared to the test results, and the accuracy of the refi ned model was verifi ed. Then, the refi ned model of the stainless steel C-section beam was simplifi ed including the constraint simplifi cation model, which considered diff erent fl ange constraints and initial imperfections, and the length simplifi cation model, which was based on diff erent length and support constraints. The comparative analysis results showed that the constraint simplifi cation model can simulate the local buckling failure mode more accurately than other models. Additionally, initial imperfections were shown to have little eff ect on the local buckling capacity; however, specimen length and the bearing constraint condition did aff ect the local buckling capacity.

A new foreign exchange model and potion pricing

Shenggang Yang,Juan Peng,Jinqiang Yang 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

A new foreign exchange model is set up in our paper to describe the performance of the exchange rate between two countries, and it catches hold of the characteristics such as mean-reversion, self-similarity and long-term dependence which are widely existent in the foreign exchange market. Fortunately, we obtain the explicit solution of the price of the European foreign exchange option, which makes it convenient to compute the price. Additionally, the quantity relations between the variables and some interesting evidences are explored by comparative static analysis and these provide the valuable empiricism for investing, hedging and evading risk.

Parametric Analysis on Elastic Buckling Performance of Low Yield Point Steel Plate Shear Wall with Two-Side Connections

Shenggang Fan,Runmin Ding,Shaoru Zeng,Chenxu Li,Chengliang Liu 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.6

The steel plate shear wall (SPSW) with two-side connections can be arranged fl exibly in the structure, and has no additional infl uence on the column, but its buckling capacity is diffi cult to be deduced directly by thin plate theory. The low yield point SPSW (LYP-SPSW) with two-side connections is proposed in this paper, including unstiff ened LYP-SPSW, cross-stiff ened LYP-SPSW and diagonally-stiff ened LYP-SPSW. The elastic buckling performance and buckling capacity of these three types of LYP-SPSWs are studied by numerical simulation. On the basis of the accurate model, a series of parametric analysis on the key factors were conducted, including the height-to-thickness ratio, the stiff ness ratio of the stiff ener, and the stiff ness ratio of the edge member, which have eff ects on the elastic buckling stress of the LYP-SPSW with two-side connections. The elastic buckling stress of the SPSW can be eff ectively increased by adding stiff eners and edge members, but it is unnecessary to use oversized stiff eners and edge members. Based on a large amount of parametric analysis, simplifi ed formulas for calculating the elastic buckling stresses of the three types of LYP-SPSWs mentioned above are proposed in this paper.

Nonlinear Finite Element Modeling of Two-stage Energy Dissipation Device with Low-yield-point Steel

Shenggang Fan,Zhixia Ding,Li Du,Chunfang Shang,Meijing Liu 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.4

Equipped with many advantages, such as low yield strength, low yield ratio, high elongation, severe plastic deformation and good energy dissipation ability, low-yield-point steel is very suitable for use in metal energy dissipation devices. Based on different materials (Q235 steel and low-yield-point steel) and different parabola openings, two types of energy dissipation steel plates underwent different yield displacements and then were assembled into a new open-hole energy dissipation device, which could achieve the goal of two-stage energy dissipation under small and large earthquakes. To obtain the failure modes and energy dissipation mechanism under the low reversed cyclic horizontal loads and observe relevant hysteretic curves and skeleton curves, the new energy dissipation device was studied and analyzed by means of theoretical analysis, experimental research, and numerical simulation analysis. Based on parametric analyses, the effects of the height, thickness and opening coefficient of the steel plate on the energy dissipation ability of the new energy dissipation device were emphasized. Thus, the key parameters affecting the energy dissipation behavior were obtained. Finally, a force-restoring model of the new energy dissipation device was put forward, and the calculation formulas were given for many parameters, including stiffness, yield displacement, yield load, ultimate displacement and ultimate load. The results show that the new open-hole energy dissipation device has the advantages of superior energy dissipation performance, obvious energy dissipation in two stages, and wide application prospects in structural seismic design.

Nonlinear model to predict the torsional response of U-shaped thin-walled RC members

Shenggang Chen,Yinghua Ye,Quanquan Guo,Shaohong Cheng,Bo Diao 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.6

Based on Vlasov‟s torsional theory of open thin-walled members and the nonlinear constitutive relations of materials, a nonlinear analysis model to predict response of open thin-walled RC members subjected to pure torsion is proposed in the current study. The variation of the circulatory torsional stiffness and warping torsional stiffness over the entire loading process and the impact of warping shear deformation on the torsion-induced rotation of the member are considered in the formulation. The torque equilibrium differential equation is then solved by Runge-Kutta method. The proposed nonlinear model is then applied to predict the behavior of five U-shaped thin-walled RC members under pure torsion. Four of them were tested in an earlier experimental study by the authors and the testing data of the fifth one were reported in an existing literature. Results show that the analytical predictions based on the proposed model agree well with the experimental data of all five specimens. This clearly shows the validity of the proposed nonlinear model analyzing behavior of U-shaped thin-walled RC members under pure torsion.

Research on the Judgement Method for Catenary Action of Restrained Steel Beams in Fire

Meijing Liu,Shenggang Fan,Yang Guo,Heyang Gui,Runmin Ding,Hang Zhou 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.2

Based on fire tests, a parametric numerical simulation on the catenary action of restrained steel beams in fire was performed by the finite element software ABAQUS. It can be known that axial constraint stiffness, rotational constraint stiffness and load ratio are key factors that affect the catenary action in fire. The formation mechanism of catenary action under ISO-834 standard fire was studied; and the judgement method for catenary action in fire was presented. The results show that: (1) when axial constraint stiffness reaches a certain value, the catenary action of restrained steel beams will occur almost at the same time; (2) with the increase of rotational constraint stiffness or load ratio, the catenary action of steel beams will occur earlier; (3) for restrained steel beams under a small load ratio, the catenary action usually occurs in fire when the mid-span deformation reaches 1/15 of the span; but for restrained steel beams under a large load ratio, the catenary action usually occurs when the mid-span deformation reaches 1/18 of the span; (4) for restrained steel beams with a large rotational constraint stiffness, the judgement method for catenary action in fire can still adopt the same method as above, which will be a little conservative.

Parametric Analysis on Hysteresis Performance and Restoring Force Model of LYP Steel Plate Shear Wall with Two-Side Connections

Yaqi Suo,Shenggang Fan,Chenxu Li,Shaoru Zeng,Chengliang Liu 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.6

Parametric analysis on the hysteresis performance of the low yield point steel plate sheer wall (LYP SPSW) with three different stiff ening confi gurations, including unstiff ened, cross stiff ened and diagonal stiff ened, was conducted using the fi nite element models which have been verifi ed by the test results. The parameters which have eff ects on the hysteretic behavior of LYP SPSW include ratio of height-to-thickness, stiff ness ratio of stiff ener, and the stiff ness ratio of the edge member. The hysteretic curves, skeleton curves and viscous damping coeffi cient-displacement curves of SPSW with diff erent stiff ening confi gurations were obtained. According to the numerical results, it can be seen that the shear resistance and hysteretic performance of LYP SPSW decrease with the increase of the ratio of height-to-thickness. The energy dissipation capacity and shear capacity of LYP SPSW can be improved eff ectively by setting cross and diagonal stiff eners, but when the stiff - ness ratio of stiff ener is greater than 10, the increase is no longer obvious. Furthermore, for steel plate shear walls without edge members, the diagonal cross-stiff ening steel shear wall can achieve better energy consumption. For steel plate shear walls with edge members, when the ratio of height-to-thickness is less than 100, a better energy dissipation can be achieved by using cross stiff ened steel plates; when the ratio of height-to-thickness is greater than or equal to 200, a better energy dissipation can be refl ected by adopting cross stiff ened steel plates. Finally, a restoring force model of the LYP SPSW with two-side connections is proposed.

Analytical Elasto-plastic Solution for Frost Force of Cold-Region Tunnels considering Anisotropic Frost Heave in the Surrounding Rock

Qiang Feng,Shenggang Fu,Chengxiang Wang,Weiwei Liu,Ying Wang,Weiguo Qiao 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.9

There is an increasing trend of tunnel infrastructure construction in cold regions due to the advance of a western development strategy. To reduce the frost damage sustained by a tunnel, it is important to consider the mechanical properties of frost heave in the surrounding rock by analyzing the anisotropic frost heave of a cold-region tunnel. This paper elaborates on the behavior of anisotropic frost heave in the rock surrounding a cold-region tunnel, and the coefficient of displacement relief is adopted to indirectly quantify the influence of the tunnel construction process. The analytical elasto-plastic solutions of the stress and deformation in the surrounding rock are derived with Drucker-Prager criteria (hereinafter referred to as the D-P criteria) by modifying the constitutive equation for the frozen surrounding rock. Finally, an example is given to obtain the influence law of the distribution of stress and deformation in the surrounding rock. The results indicate that the plastic radius and frost force calculated by considering isotropic frost heave are greater than those obtained by considering anisotropic frost heave. The influence of the related parameters also analyzed. Some useful insights are provided for future numerical simulations and the design and construction of cold-region tunnels.

Direct Strength Method for Stainless Steel Lipped Channel Columns Undergoing Local Buckling

Meihe Chen,Shenggang Fan,Chenxu Li,Shaoru Zeng 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.6

This paper reports the results of a numerical investigation on the influence of local buckling on the ultimate strength and design of locally fixed-end and globally pined-end stainless steel lipped channel columns in compression. The elastic buckling load is a key parameter in predicting the design strength of stainless steel lipped channel columns. Elastic buckling loads under simple–simple, clamped–clamped and experimental boundary conditions have been compared. To extend the data, a finite element model of stainless steel lipped channel columns has been developed and verified against the test data. Parametric studies on the stainless steel lipped channel columns were performed. The test results are compared with the strength predictions from direct strength method (DSM), indicating that DSM included in North American specification is unsafe, but the DSM proposed by Becque et al. is conservative. A modified DSM equation was proposed and has been proven to accurately predict the ultimate capacities of the stainless steel lipped channel columns in compression