Deformation and Failure of the Glass Fiber Reinforced Composite Cylindrical Explosion Vessel
Author:Gan Yun Dan
Supervisor:zhang qing ming
Explosion vessel is the sealing device that limits explosion shock wave and detonation products.It can avoid pollution and destruction after explosion.What’s more,it is very convenient to help observing explosion and detonation process.So far,explosion vessel has been widely used in various fields like public security,national defense scientific research and industrial production.There are several weaknesses of current metal explosion vessel,such as low intensity,sensitive to cracks,internal defects and size effect,diminishing its actual bearing capacity and can’t satisfy the requirement of big quantitative.With the development of the new material about lightweight,high strength composite,it is of great significance to research composite explosion vessel.Therefore,the deformation and failure of the glass fiber composite cylindrical explosion vessel has been studied in this paper.Compared to the spherical vessel,composite cylindrical explosion vessel is easier to be made and more widely used.In a composite cylindrical explosion vessel,the tube body is the main bearing part.To simplify the problem,we focused our attention on composite winding metal liner cylindrical structure with the length to diameter ratio of 2.5:1.The main research contents and conclusions are as follows:(1)We established the 3-d digital image correlation test system(3D-DIC),using two cameras to form a binocular observation system,like the human eyes system.The 3-D information on the surface of the object can be obtained by analyzing the parallax of the same image point from different images.The method can measure the dynamic deformation of the tube body under the action of internal blast.This method not only removes interference from explosion product,but also overcomes the adverse impact of vertical deformation of the tube body and measuring surface.(2)A series of experiments on tube body with different winding way under different explosive has been done.When charge relative quality(η)is no more than 1.21%,the largest hoop strain is proportional to η.All of the maximum hoop deformations or destructions occurred during the first tensile phase in the first period.If η is the same,although the winding way of composite has minor effect on the deformation,it has a significant impact on internal damage of the tube body,which are mainly the clearance values between the composite and inner,delamination of the composite.The time frequency characteristics of vibration of tube body under different η were obtained by the empirical mode decomposition and Hilbert transform.The plastic deformation of inner enhanced with the increasing of η,while frequency corresponding to the maximum deformation decreased.When η is the same,the winding way has minor effect on frequency corresponding to the maximum deformation of the tube body.The maximum difference is about 4%.(3)The effects of winding way of composite,inner and head on deformation and failure of tube body were studied by numerical simulation.The result showed that the deformation and failure was minimum when tube body was an interlaced helical winding combined with hoop winding with a thickness ratio of 1:1:2,and a thickness ratio of 1:8 for inner to composite.The inner lowered the destruction of the tube body from the explosive load and resonance induced.The composite layer is gradually destroyed,and from outer to inner,the damage included matrix,fiber tensile fracture and delamination of composite.The damage of tube body included bending deformation,separation of inner from composite.We also obtained the relationship between maximum deformation of axial and radial of inner with the charge proportion of distance.(4)We analyzed the deformation and failure mechanism of the tube body,put forward the strength criterion suitable for damage of the tube body and established a theoretical model of the tube body deformation.We obtained the relationship between hoop deformation of tube body with η.Axial and radial deformations calculated by theoretical model had a good agreement with the experimental results.The deformation or destructions of the tube body can be predicted by the charging quality and the proportion of distance.This work provides important insights for the design of glass fiber composite cylindrical explosion vessels.