Dynamics Analysis Of Multiple Cracks Beam With Considering The Effect Of Steel Reinforced Constraints

With the complexity of engineering structure,the reinforced concrete beams are widely used in engineering structure.There are a variety of small cracks in reinforced concrete beam inevitably because the effect of the construction process as well as during the service load and the environment.The small cracks will expand and evolve to macroscopic cracks under the action of external loads and environmental factors.Cracks not only make the static mechanical properties of reinforced concrete beam structure changes,but also affect the dynamic characteristics of reinforced concrete beam,which in turn lead to a decline in the carrying capacity of the beam structure and further threaten the structural safety.In addition,when cracks in reinforced concrete beam expansion occurs,the beam structure may change a non-resonant excitation state into a resonance state under the external excitation.Which leads to further significant changes in the structure of concrete beam and stimulate the accelerated expansion of cracks in reinforced concrete beam structure of the service life of the rapid decrease.Therefore,it is necessary to study the dynamic analysis of reinforced concrete structure with cracks.It will also provide a theoretical basis for foundation engineering structural performance testing and security assessment.Reinforced concrete beam with multiple cracks in this papper is composed by the two kinds of materials including steel and concrete.The mechanical properties is different from the components of a single material medium.The crack of reinforced concrete beam is affected not only by the performance of concrete,but also by the reinforced confinement effect.Therefore,dynamic performance crack in reinforced concrete beams are not exactly the same as a plain concrete beam crack crack structure performance.Dynamics characteristics analysis of reinforced concrete beams with multiple cracks has been studied in this paper.The main research work covers the following aspects:Chapter 1:The research background,research status,research methods and research significance of the static and dynamic problems about reinforced concrete beams for dynamics characteristics analysis is introduced.Chapter 2:Based on the Euler-Bernoulli theory,using the Hamilton energy principle,The dynamic equations of reinforced concrete with multiple cracks beam considering reinforced constraints effect and stress concentration cracks is established.Chapter 3:Firstly,analysis the question of free vibration of a single crack of reinforced concrete beams.The influences of crack position,crack depth and the reinforced constraint effect for the natural frequency of a single crack of reinforced concrete beams are discussed.Chapter 4:Basing on dynamic equations of reinforced concrete with multiple crack beam in the previous chapter.The influences of multiple cracks in different locations,different crack depths,different crack spacing and the reinforced constraint on the natural frequency of the beam are discussed.The comparison chart is made of the modality amplitude.Chapter 5:Analysing the dynamic response of reinforced concrete beam with multiple cracks under harmonic loads.The influences of reinforced constraint effect,crack depth and crack position on the displacement response of reinforced concrete beams under different load are discussed.The final:Conclusion the paper and the further research about reinforced concrete beam with multiple cracks considering reinforced constraints is introduced in the future.