Study On Resistance Function Of Reionforced Concrete Beam Of Drop Hammer

In recent years, a series of low-intensity wars and terrorist bomb attacks attrackimperious needs and challenge for the antiknock of important economic, military andcivil constructions. Reinforced concrete structures become the preferred design ofblast-resistant structures because of its excellent mechanical properties and high massdensity. The study of the dynamic response of reinforced concrete beams, plates,columns and other structural elements and the entire structure under the occasionalextremely strong impact loading, has important theoretical significance andengineering value for the current design of the building structure antiknock security.The simplified equivalent single degree of freedom (SDOF) approach has thefeatures of clear concept, simple and practical to use, which make it to be the mostcommonly used method in the antiknock performance analysis of building structuresinternationally. A key difficulty of SDOF is the determination of the resistance function.At present, the resistance function access mainly by static theoretical analysis andexperiments. The use of static methods to obtain the resistance function of the buildingcomponents is a more natural approach, but it does not reflect the dynamiccharacteristics of components, such as the strain rate effect. Combined with the SDOFtheory, this article explores the use of drop hammer loading method to realize adynamic loading, to directly access the resistance function of components dynamicallyand to determine its yield point, by measuring the acceleration of the drop hammer andthe displacement of components.Firstly the SDOF module of Fixed-Fixed beam under concentrated load isestablished, and the method using drop hammer to access the resistance function ofcomponents is proposed through the equation of motion. Second, the dynamic processof the drop hammer impacting on reinforced concrete beam is simulated to design themethod by using the non-linear dynamics finite element program AUTODYN. Then theexperiments are carried out and the results are compared with the static theory. Thecomparison validates the drop hammer loading method being reasonable and feasible.