Study On Mechanical Behavior Of Unidirectional Cold Bending Hollow Laminated Glass

Hollow laminated glass is an ideal type of curtain wall glass with good thermal insulation and safety performance.Among the methods to realize the curved effect of glass curtain wall,the cold-bending has great development potential.However,the research on cold-bending is limited at home or abroad.Therefore,it is of great significance to research the mechanical behavior of hollow laminated glass during cold bending and its working state after cold bending.Twelve specimens were made and unidirectional cold bending test and uniformly distributed loading test were carried out to study the influences of thickness of single sheet glass,cold bending radius,cavity thickness and PVB thickness on the mechanical properties of cold bending hollow laminated glass.Unidirectional cold bending test makes glass bend unidirectional according to arc curve by applying displacement to two short sides.Based on the cold bending test,the uniformly distributed load was applied to the surface of the specimen with a maximum of 10 k Pa,so as to simulate the extreme wind load it would bear during normal operation.In unidirectional cold bending test,the max principal stress linear change with the increase of cold bending displacement.The max principal stress focus on the long side of tensile panel,and its maximum value locate in its midpoint,also it decrease toward the edge.Increasing the thickness of single sheet glass and decreasing the cold bending radius will increase the maximum principal tensile stress.Layer displacement increases linearly with the increase of the cold bending displacement.The increase of the thickness of the single piece of glass,the decrease of the cold bending radius and the increase of the cavity thickness will increase the layer displacement.In uniformly distributed load tests,the max principal stress linear change with the increase of with the uniformly distributed load.The position of the maximum max principal stress transferred from the laminated glass part long-side-midpoint to the monolithic glass part long-side-midpoint.The max principal stress focus on the long side of each glass panel.Max principal stress of long-side distributed more even in monolithic part.Reducing the cold bending radius can significantly increase the max principal stress caused by the coupling of cold bending and load action.The central displacement increases linearly with the increase of uniform load,and the reduction of cold bending radius can increase the central displacement,but not obvious.Layer displacement tends to decrease with the increase of uniform load,and reducing the cold bending radius can obviously increase layer displacement.The software ABAQUS was used to carry out the finite element numerical simulation of unidirectional cold bending test and uniformly distributed load test for each specimen.The simulated max principal stress results were in good agreement with the test results,and the stress distribution rules were similar.It can be considered that the finite element simulation can better restore the material properties and boundary conditions of cold bending hollow laminated glass.According to the actual boundary conditions and the experimental data,the calculation parameters are introduced after considering the effect of cold bending.A simplified formula for calculating the maximum principal tensile stress and central deflection of cold bending hollow laminated glass based on the current specification is presented.The checking show that the formulas has high accuracy.