Research On The Dynamic Response And Rebound Mechanism Of Blast Door Subjected To Blast Loading

A small amount of entrances must be built in national defence and civil defenceengineering due to the needs for staff and equipment cross through, aeration, watersupply and drainage, smoke discharge and other purposes. These entrances mightbecome the entry or channel of blast shock wave at wartime, by which the destructivevibration environment that was produced after the blast shock wave would enter into theengineering and result in casualties and failure of equipments and command systeminside. However, the blast door, as the most important protective equipment of entrance,would play a decisive role on guaranteeing the overall safety of engineering during thewartime. In this paper, the theoretical and numerical simulation research on dynamicresponse and rebound mechanism for both typical stiffened steel blast door and concretefilled steel and steel tube blast door subjected to blast loading has been conducted. Themain results are as follows:1. The dynamic response and resistance of a typical stiffened steel blast door wasevaluated by a numerical model considering the effects of both strain rate andtemperatures. In meanwhile, all the factors that influence and regulate the blast-resistantproperties of stiffened blast door are further analyzed including the number and layoutsof stiffeners, thickness and height of beam web, thickness and width of beam flange,surface plate thickness, explosion distance, charge weight, duration of blast loading,boundary conditions and filled with aluminum foam etc. By using the dimensionalanalysis method, the more reasonable model for engineering calculations wassuccessfully established.2. A numerical model of concrete and confined concrete was establishedconsidering the effect of strain rate, which is then verified through a series ofexperimental data obtained before. On basis of the model, the research was focused onthe evaluation of typical concrete filled steel and steel tube blast door in thecorrespondence with dynamic response and resistance. All the factors were sufficientlyanalyzed including the existing steel tube, concrete strength inside and outside steel tube,thickness of steel tube and duration of blast loading.3. According to the dynamic method of distributed parameter system, the blastdoor was assumed to be a beam and plate and then the exact analytical formulas of rebound force on blast doors in elastic phase were derived, furthermore, the sheardynamic factors (SDF) of beam and plate were obtained too. All the factors wereanalyzed and deeply researched including the side-length ratio, duration, damping ratio,loading style and negative phase of blast loading etc.4. During using the dynamic analysis method for the equivalent single degree offreedom (SDOF) system, the blast door was assumed to be a SDOF system. Thecalculation formulas of rebound resistance for blast doors in elastic phase subjected toblast loading were derived. In meantime, the displacement dynamic factor (DDF) andelastic rebound curves subjected to six common loads were obtained too.5. The research further established a finite element model of typical stiffened steelblast door with regard to the door frame-hinge-latch nonlinear contact effect when therebound mechanism in plastic phase were investigated by the numerical similation. Therelevant influential effects of gaskets, modulus of elasticity, hinge and latch numbers,scaled distance, duration on the rebounding regulations were fully taken into anindividual consideration in the study. Finally, the propose and suggestions for rebounddesign of blast door were shown in the paper as well.