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Chen G.,Kunming University of Science and Technology | Wen J.,Liuzhou OVM Machinery Co.
Journal of Mechanical Science and Technology | Year: 2015

Although there are a large number of studies on large rolling bearings, analyses are seldom for the effects of size and raceway hardness on their fatigue life. In this study, taking the four contact-point ball bearings as an example, the fatigue lives of large rolling bearings with different structure sizes were calculated through the stress life (σ-N), strain life (ε-N) and international standard (ISO) methods, respectively. The maximum contact force and subsurface stress in the raceway were obtained with the finite element method. At the same time, the effect of raceway hardening depth on bearing life was taken into account. Results showed that the effect of raceway hardening depth on the life of large rolling bearing was obvious. Thus, the raceway hardening depth cannot be ignored when calculating the fatigue life of large rolling bearing. When used with the load at the same level, the rolling bearing with larger size usually had less the fatigue life. © 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Shen Y.,Tongji University | Lu S.,Liuzhou OVM Machinery Co. | Li F.,Tongji University
Advances in Materials Science and Engineering | Year: 2015

Carbon fibre reinforced polymer (CFRP) is currently used to reinforce buildings in civil engineering in the common forms of sheets, while the utilization efficiency of a CFRP materials greatly decreased when the CFRP material is directly bonded to the structure because of the lack of the effect of the exertion of a prestress. A paper spool-inspired anchoring method is proposed to overcome the shearing problem in the anchoring system through the friction between layers. Anchoring and jack-up tensioning devices for CFRP sheets are also designed and produced. A prestress is successfully applied to single and multiple CFRP sheets (80% tensioning strength is achieved), thus verifying the tensioning effect of the prestress. Based on these results, prestressed concrete flat slabs were designed with pretensioned CFRP sheets. The corresponding mechanical properties of the concrete flat slabs are tested to verify the feasibility of using CFRP sheets to apply a prestress. The results show that the uniformity of the fibre stress during the tensioning of the CFRP sheet is the key to the success of the application of the prestress. © 2015 Yin Shen et al.

Li F.,Tongji University | Xie Z.,Liuzhou OVM Machinery Co. | Guo X.,Tongji University
Applied Mechanics and Materials | Year: 2012

When the bridges broaden with seamless technology, there are differences between the existing bridge and the new bridge in design, construction and service. Because of concrete creep and shrinkage, temperature effect and prestress loss, there are stress defects in the seam, which will affect the service and safety. The current methods for the seam in foreign and domestic, such as plant steel and semi-rigid connection method are passive measures based on structure exiting state, which cannot ensure the long-term performance of the seam. © (2012) Trans Tech Publications, Switzerland.

Deng L.,Guangxi University of Technology | Deng L.,Guangxi University | Chen H.,Guangxi University of Technology | Yan L.,Guangxi University | And 3 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

The independently developed carbon fiber reinforced plastics (CFRP) an chorage and tension devices were adopted to carry out tests on the flexural behav ior of 8 model specimens of reinforced concrete beams strengthened with different forms of CFRP plates. Influence of the side-strengthening of the prestressed CFRP plates on the strengthened RC beam was studied, including the carrying capacity of the beams, the deformation and the cracks of the using stage, the concrete compressive strain, the stress distribution of the CFRP plates in the using stage and the ductility. Experimental results show that the side-bonded with the prestressed CFRP strengthening method can obviously increase both the cracking load and the yield load of the flexural members, reduce the deformation and the crack of the member during the using stage. The reliable anchorage at both ends can prevent the debonding failure. At the same time, the ductility performance of the concrete members can be increased by making the most of the material strength.

Zhu W.,Harbin Institute of Technology | Zhu W.,Liuzhou OVM Machinery Co. | Qin X.,Liuzhou Road and Bridge Construction Management Office | Huang Y.,Liuzhou OVM Machinery Co. | Zhu X.,Guangxi University of Technology
Applied Mechanics and Materials | Year: 2012

This paper presented a new kind of strand cable system, which cable body was composed by the strands isolated by HDPE sheath. The isolation extrusion method were used in anchoring the bundle of strands on the anchorage of both cable ends. The type of the cable-stayed structure, features, test and engineering design and application were described. The result shows that the cable system has compact anchorage structure and small diameter, which can be more stable to reach the correlative standards requirement on static load and fatigue performance. The cable system provides a new choice in the bridge construction and had been widely applied in China since 2005. © (2012) Trans Tech Publications.

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