Study On Interface Failure Of The Film-Substrate Structure With Pre-Stretching Deformation

In industrial applications such as transfer printing,wall climbing robots,etc.,which utilize the adhesion properties between materials to achieve the working objectives,the range of variation of the adhesive strength between the adhesive object and the substrate is a key factor for its realization.At present,there are a lot of studys on the peel test of the Kendall model and its application,especially for the relationship between the adhesive strength and the peel angle.However,the relationship between the peel force and the peel angle of the thin film has not been applied in the above fields.One of the reasons is that the loading method of the thin film load in the Kendall model is different from the actual applications.Therefore,according to the actual applications,a new peel test model is established based on the Kendall model in this paper.At the same time,on the basis of this model,in order to further expand the range of variation of the adhesive strength,this paper proposes an adhesive strength enhancement method based on the film stiffening effect.Therefore,this paper mainly explores the influence of different initial peel angles and different pre-tension on the adhesive strength between the elastic film and the substrate by means of experimental method,finite element method and semi-analytical method respectively,reveal the change reason of interfacial adhesive strength and fracture mechanism.At the same time,the application prospect of the model is introduced in this paper.The main study work and achievements can be summarized as follows:(1)By designing the peel test devices,the relevant experiments were separately carried out to investigate the influence of the different initial peel angle and the pretension of the film on the adhesive strength between the film and substrate.It can be obtained from experimental results that the smaller the initial peel angle or the larger the pre-tension,the greater the peel force required when the crack between the film and the substrate starts to expand,that is,the greater the adhesive strength.(2)Using the finite element method,the experimental part of the peel test was simulated.The simulated results not only verify the reliability of the experiments but also reveal that the pre-tension can further reduce the peel angle of the film when the crack between the film and the substrate begins to expand,thereby increasing the adhesive strength.At the same time,the finite element method was used to explain the essential reason for reducing the peel angle to improve the adhesive strength from the perspective of the stress distribution of the adhesive part and the range of the fracture process zone.(3)Using the semi-analytical method,the governing equations of the peel test model are solved,and the required peel force of the film and the range of the fracture process zone are obtained under different initial peel angles.Comparing the calculation results with the results obtained by the experimental and finite element methods,the reliability of the above two methods is proved.(4)The relevant experiments were designed to simulate the transfer printing,supplemented by the finite element simulation,which proves that the peel test model can be applied in the fields of transfer printing and wall climbing robots,and has certain feasibility and engineering application prospect.