Papers by Keyword: Deflection

Abstract: This paper presents a three-dimensional entity model to analyze the creep effection of PC continuous rigid frame bridge and simulate the impact of longitudinal cracks at the bottom of mian span on the deflection briefly with ANSYS software. The result shows that creep amplifies the deflection of bridge and makes the position of maximum deflection move to the center of mian span. And the longitudinal cracks of mian span don’t make great contribution to the deflection of PC continuous rigid frame bridge directly. Actually, the cracks change the stress state of the bridge’s section, which results in the risk of web cracking and further the stiffness degradation of structure. The stiffness degradation increases the defection of bridge to a great degree finally.

Abstract: Steel Reinforce Concrete Beam (SRCB) has a better flexural strength and excellent performances of ductility and seismic resistance in contrast to reinforce concrete beam.Six SRCB have been done with different compressive strength of concrete,rebar ratio,rebar cover thickness and steel cover thickness. The paper analyses the character of deflection and crack development process in following aspects: the development of maximum width and average width of crack, the law between strain of rebar and steel with the width of crack and the crack closing character. Experimental study indicates that the deflection and crack development can be devided into three stages. SRCB with reasonable rebar and H-section steel arrangement manner has excellent serviceable performance,such as deflection, resistance to crack, crack width and crack closing performance.

Abstract: The paper study the deformation characteristics of the Prefabricated bamboo reinforced porous concrete slab through points with four points focused beam loading method. The results show that flexural behavior of prefab slab can be improved by adding bamboo reinforcement. Along with the increase of bamboo reinforcement ratio, deflection of prefab board will gradually reduce. Through the loading deflection curve, we can discover that the bamboo reinforced prefab slab with the linear elastic state, and the slab can withstand a certain load after cracking. Bamboo reinforced with strengthening and toughening effect for porous concrete, prefabricated bamboo reinforced porous concrete plate can be used better in slope protection engineering.

Abstract: In this paper, the ram of boring and milling machining center is taken as the research object. A new method that hydraulic pull rods compensation is proposed to solve the problem of deformation compensation of long stroke ram of boring and milling machining center. Firstly, the method of finite element analysis is used to get the laws of ram deformation and the relationship curve between the ram deformation and the stroke of ram. Secondly, the preliminary calculation value of pull rods compensation force is derived based on the theoretical analysis of material mechanics. The relationship curve between compensation force and the stroke of ram is obtained by finite element analysis and polynomial least squares method. Finally, the analyzed results are as follows: the laws of ram deformation distribution is accurately predicted by the used method, the deflection error of the ram is well controlled,and the machining precision is significantly improved.

Abstract: Ionic Polymer Composite Material (IPMC) is a flexible material and has concealed many benefits to inspire the scientists and researchers to explore its physiognomies for real-world applications in various fields. Currently, the research area of IPMC can be alienated into two branches. One deals with the upgrading of the material properties to make it further advantageous and dependable while the other encompasses the consideration of new application capacities. In this paper, a new application of IPMC is recommended to stimulate a rigid link that can imitate a bionic knee joint for a grass hopper. Secondly, force-deflection mathematical model has been developed for the proposed design to investigate the amount of deflection that can be achieved by a certain force provided by the IPMC material strips. In this paper, the model is derived for the upward movement of the link; however the same model can be applied to the reverse direction because of the unanimity of the material properties and specifications.

Abstract: Torque, as an important indicator of the engine, is the reflection of performance of cylinder-embedded piston engine. In power stroke, torque varies at different moments, so if the impact of structural parameters on torque needs to be analyzed, the values of torque in power stroke need to be added together and divide lasting time. The average effective torque is the average of the torque generated by explosive force during the entire power stroke, which overcomes the disadvantages of the instantaneous torque which can not reflect the changes in power process. Therefore, the influence of each structure size on the force transmission performance can be analyzed with maximizing the average effective torque. It is concluded that for increasing the average effective torque, the radius of the hinge center trajectory of cap R should be increased, and the length from rotating center O to the trajectory of piston H should be decreased. The length of rod L has little influence on the average effective torque. However, if there is a too large D-value between R and H, the rod may deflect seriously, so that the piston side force increases, causing the piston wear and tear. So the values of R and H should be selected with specified conditions in the design.

Abstract: Large span bridges are very important infrastructure of the nations. The enormous investment and significance in state economy make them get more and more recognition. At present, the technology of the safety monitoring of bridges is becoming a hotspot in both academic and engineering field. Now, safety monitoring systems of the structures have been applied to many large bridges in the world. Among all these parameters which can indicate the safety status of bridges, the deflection is indispensable. Although there are lots of sensors now used to measure the degrees of the deflection, it is still very scarce that the sensors can be made for long-distance, real-time and automatic online completely. The photo-electricity and liquid level deflection sensors (PLLD) introduced here are cheaper and of better-automaticity and higher precision and can work online continuously without contact. This paper will show the structure, performance and theory of our new sensor based on ARM7 in detail. In the end, a concrete application instance in XiaoGou bridge of ShanXi province will be given.

Abstract: This paper reviews the research on the deflection of orthotropic saddle membrane under the external snow load. First the authors build the model of orthotropic saddle membrane under the snow load. Second we deduce the equations set of the saddle membrane which has the effect of pretension. Then we solve the equations set with the perturbation method. So we obtain the relational expression between the maximum deflection of the membrane’s centre point and the external load. At last, suppose that the load was determinate, the authors analyze the change of the deflection of the centre point of the membrane with different pretensions, side lengths and other parameters.

Abstract: Flapping wing aerial vehicles continue to be a growing field, with ongoing research into unsteady, low Reynolds number aerodynamics and micro fabrication. However research into deformation and stress of flapping wing continues to lag, especially based on composites model. One flapping cycle was divided into twelve segments, and maximum defmortion and stress were calculated in each segment. The results show that the maximum sdeformation at the beginning stages of downstroke is 19% larger than the maximum deformation at the beginning stages of upstroke, and the maximum stress at the beginning stages of downstroke is 29.9 larger than the maximum stress at the beginning stages of upstroke. This research is helpful to answer that why insect wings are so perfect through long evolution, thus improving the design of flapping-wing aerial vehicles.

Abstract: According to transverse load test on two half-scale energy-saving wall panels with different space. It is analyzed these panels with failure processes, failure modes, ultimate bearing capacity, load-deflection curves, concrete load-strain curves and steel load-strain curves. The results show that failure modes, flexural stiffness and ultimate strength of panels are affected by ratio of steel.