Study on Flexural Behavior of Pre-Stressed Concrete Hollow Slabs Strengthen with CFRP

2013 ◽  
Vol 446-447 ◽  
pp. 1413-1416
Author(s):  
Bo Wang ◽  
Juan Han

The purpose of this paper is to focus on studying its flexural behavior after different damages pre-stressed concrete hollow slab is strengthened with CFRP. By the experimental method, twelve residential pre-stressed concrete hollow slabs are tested under concentrated force at the two points of the symmetrical load in order to analyze both flexural behavior and effects factored by different bonding modes. The conclusion can be drawn that the flexural behavior of pre-stressed concrete hollow slabs strengthened with CFRP is well-tried. It provides design suggestions and reference for pre-stressed concrete hollow slabs strengthened with CFRP, and also provides an experimental basis for the repairing and reinforcing practical engineering application in Wenchuan disaster area.

2013 ◽  
Vol 351-352 ◽  
pp. 592-595
Author(s):  
Juan Han ◽  
Yin Liang

The purpose of this paper is to focus on studying its flexural behavior after different damages prestressed concrete hollow slab is strengthened with CFRP.By the experimental method, twelve residential prestressed concrete hollow slabs are tested under concentrated force at the two points of the symmetrical load in order to analyze both flexural behavior and effects factored by different bonding modes.The conclusion can be drawn that the flexural behavior of prestressed concrete hollow slabs strengthened with CFRP is well-tried.It provides design suggestions and reference for prestressed concrete hollow slabs strengthened with CFRP, and also provides an experimental basis for the repairing and reinforcing practical engineering application in Wenchuan disaster area.


2011 ◽  
Vol 368-373 ◽  
pp. 519-526
Author(s):  
Ru Heng Wang ◽  
Juan Han

The purpose of this paper is to focus on analyzing its flexural capacity under concentrated force at the two points of a symmetrical load after the 21 old and new different degrees of damege to prestressed concrete hollow slab is strengthened with CFRP by the different paste modes and paste quantities.Meanwhile,according to the initial loading of prestressed concrete hollow slab specimens in which the plastic state, based on the elastic-plastic theory,it presents the theoretical calculation formula of the ultimate bearing capacity produced with the consideration of the secondary load of the prestressed concrete hollow slab strengthened with CFRP.Through the experimental value of the old and new specimens compared with the theoretical one, It provides design suggestions and reference for the prestressed concrete hollow slab strengthened with CFRP,and provides an experimental basis for the repairing and reinforcing practical application of the Wenchuan disaster area.


Author(s):  
S. Li ◽  
J. Ruan ◽  
B. Meng ◽  
W. A. Jia ◽  
H. Y. Xie

A 2D electrohydraulic proportional directional valve is proposed, which integrates both direct and pilot operation of the valve. In this valve, the output magnetic force of the proportional solenoid is converted to rotate the spool through a thrust-torsion coupling and thus the pressure in the valve sensitive chamber is varied. The varied pressure exerted on the areas of the spool end produces a hydrostatic force to move the spool linearly, which will rotate the spool reversely. Theoretical analysis is carried to the proposed valve and the effects of the key geometric parameters on the dynamic characteristics of the 2D valve and stability are investigated. Experiments are also designed to access to the characteristics of the valve working under direct and pilot operation. The 2D electrohydraulic valve can work properly for both direct operation and pilot operation. The hysteresis and frequency response are measured and the results are within the acceptable range in practical engineering application required of the directional proportional valve.


2021 ◽  
Vol 8 ◽  
Author(s):  
Dehui Ye ◽  
Jie Tan ◽  
Yabin Liang ◽  
Qian Feng

The pounding tuned mass damper (PTMD) is a novel passive damper that absorbs and dissipates energy by an auxiliary tuned spring-mass system. Viscoelastic materials are attached to the interface of the limitation collar in the PTMD so that the energy dissipation capacity can be enhanced. Previous studies have successfully demonstrated the effectiveness of PTMD at room temperature. However, in practice, the PTMD may face a broad temperature range, which can affect the mechanical properties of the viscoelastic materials. Thus, the study of vibration control effectiveness of PTMD at different temperatures is of great significance for its practical engineering application. In this paper, a series of experiments were conducted to investigate the performance of a PTMD in a temperature-controlled environment. A PTMD device was designed to suppress the vibration of a portal frame structure and tested across environmental temperatures ranging from –20°C to 45°C. The displacement reduction ratios demonstrated the temperature robustness of the PTMD. Additionally, the numerical results validated the accuracy of the pounding force model and the performance of PTMD.


2014 ◽  
Vol 902 ◽  
pp. 344-350
Author(s):  
Xiang Jia Li ◽  
Ning Dai ◽  
Wen He Liao ◽  
Yu Chun Sun ◽  
Yong Bo Wang

Offsetting of measured data, as a basic geometric operation, has already been widely used in many areas, like reverse engineering, rapid prototyping and NC machining. However, measured data always carry typical defects like caves and singular points. A fault-tolerant offset method is proposed to create the high quality offset surface of measured data with such defects. Firstly, we generated an expansion sphere model of measured data with the radius equivalent to the offset length. Secondly, using the computational geometry application of convex hull, we acquire the data of outermost enveloping surface of this expansion sphere model. Finally, we use local MLS projection fitting method to wipe out existing defects, and generate the high-quality triangular mesh surface of the offset model. The offset surface generated by this method is suitable for practical engineering application due to its high efficiency and accuracy.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xue-Qin Li ◽  
Lu-Kai Song ◽  
Guang-Chen Bai

PurposeTo provide valuable information for scholars to grasp the current situations, hotspots and future development trends of reliability analysis area.Design/methodology/approachIn this paper, recent researches on efficient reliability analysis and applications in complex engineering structures like aeroengine rotor systems are reviewd.FindingsThe recent reliability analysis advances of engineering application in aeroengine rotor system are highlighted, it is worth pointing out that the surrogate model methods hold great efficiency and accuracy advantages in the complex reliability analysis of aeroengine rotor system, since its strong computing power can effectively reduce the analysis time consumption and accelerate the development procedures of aeroengine. Moreover, considering the multi-objective, multi-disciplinary, high-dimensionality and time-varying problems are the common problems in various complex engineering fields, the surrogate model methods and its developed methods also have broad application prospects in the future.Originality/valueFor the strong demand for efficient reliability design technique, this review paper may help to highlights the benefits of reliability analysis methods not only in academia but also in practical engineering application like aeroengine rotor system.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tingrui Liu

Vibration control of the blade section of a wind turbine is investigated based on the sliding mode proportional-integral (SM-PI) method, i.e., sliding mode control (SMC) based on a PI controller. The structure is modeled as a 2D pretwisted blade section integrated with calculation of structural damping, which is subjected to flap/lead-lag vibrations of instability. To facilitate the hardware implementation of the control algorithm, the SM-PI method is applied to realize tracking for limited displacements and velocities. The SM-PI algorithm is a novel SMC algorithm based on the nominal model. It combines the effectiveness of the sliding mode algorithm for disturbance control and the stability of PID control for practical engineering application. The SM-PI design and stability analysis are discussed, with superiority and robustness and convergency control demonstrated. An experimental platform based on human-computer interaction using OPC technology is implemented, with position tracking for displacement and control input signal illustrated. The platform verifies the feasibility and effectiveness of the SM-PI algorithm in solving practical engineering problems, with online tuning of PI parameters realized by applying OPC technology.


2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Gang Zheng ◽  
Yawei Lei ◽  
Tao Cui ◽  
Xuesong Cheng ◽  
Yu Diao ◽  
...  

The uniform rigidity ring model is commonly used to design the segmented structures of shield tunnels. However, model tests have been primarily used to study the transverse effective rigidity ratio η with a concentrated force, which is notably different from realistic loading patterns. To obtain more reasonable η values, in this study, tests were performed with a concentrated load on an experimental bench and with a realistic loading pattern in sandy soil in a rigid steel tank. Three types of segmental ring models were designed and tested: straight-jointed, stagger-jointed, and uniform rings. The test results indicated that the η values of the stagger-jointed assembly mode were clearly larger than those of the straight-jointed assembly mode under both loading patterns. η increased as the load increased under the realistic loading conditions, whereas η decreased as the load increased under the concentrated load. More importantly, the η values derived from the realistic load tests were considerably larger than those derived from the concentrated load tests for both assembly modes (i.e., 0.423–0.672 and 0.587–0.761 for the straight-jointed and stagger-jointed assembly modes, respectively), and the former should be recommended for practical engineering applications. Furthermore, formulas relating η to the ratio of the cover depth to the tunnel diameter were proposed for sandy soil.


2013 ◽  
Vol 838-841 ◽  
pp. 214-218
Author(s):  
Dong Li

Before the construction of the deep pit foundation, we must choose a project. Although there aren't many projects to be chosen as usual, we often feel that it's a very complex and hard work. Actually there is no a mature and general model to use. In this paper, the author attempted to use the theory of fuzzy math to establish a former to select the best project, meanwhile provided two ways to solve how to quantify the qualitative targets and how to determine the weights of the targets. Finally they were confirmed to be useful and successful by a practical engineering application. It is worthily to popularize these scientific methods in construction and management in deep foundation pits.


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