Statistical Analysis Of Mechanical Penetration Properties Of Multivoid Materials

Foaming material is a kind of gas-solid mixed multi-air heterogeneous material.In the construction industry,foaming material is usually connected with the steel wire mesh through the ventral wire to form a 3D structure,which is widely used in prefabricated building structures as a thermal insulation material.Due to the multi-void non-uniformity of foaming material,the penetration process of ventral filament through foaming material shows strong random characteristics.With the increase of foaming material thickness,the random characteristics of penetration process is gradually difficult to ignore,which brings great difficulties to the design of production equipment and the determination of process parameters.Previous mechanical studies on foaming materials mainly focus on elastoplastic deformation and mechanical creep of foaming materials,but lack of research on local continuous deformation of foaming materials in the penetration process,and the penetration resistance is difficult to be directly calculated by theoretical formula.Based on the structure and working conditions of vertical screen forming machine,which is the production equipment of polystyrene board with wire mesh,this thesis studies and analyzes the change of penetration resistance of polystyrene board with multi-hollow materials in the process of penetration.The main research contents and results are as follows:(1)Through the analysis of the structure and working conditions of the prototype machine,the variation range of various working conditions during the penetration process of the prototype machine was obtained,and the basic design requirements of the experimental platform were determined.According to the similarity principle,the key structural parameters of the experimental platform were determined and the structural scheme of the experimental platform was designed.The control system with PLC as the core was set up,and the data acquisition system scheme and the acquisition method of penetration resistance were determined.A large number of penetration tests were carried out on the test bench under the working conditions of the prototype,and the data samples of the penetration resistance were obtained,which laid a good foundation for the statistical analysis of the penetration resistance.(2)By observing the penetration resistance curve of polystyrene plate,it can be seen that the penetration process can be divided into transient and steady-state stages.The analysis of the distribution characteristics of penetration resistance in the steady-state stage showed that the accumulation and slippage of foam particles at the front of intubation was a nearly smooth random process,and the penetration resistance obtained on the experimental platform had significant statistical characteristics,which could reflect the general process of the penetration process.Then,a prediction model of the steady-state penetration resistance was established,and the regression analysis of the model parameters was carried out,and the estimated values of the prediction model parameters were obtained.The single-factor tolerance analysis of insertion speed and angle which may affect the penetration process was carried out.The results showed that the penetration resistance slope increases with the increase of the velocity,and the velocity correction coefficient of the prediction model was obtained through experiments.Insertion angle had no significant effect on penetration resistance.(3)The analysis of the penetration process of intubation with different tip shapes showed that the transient state of the penetration process was significantly correlated with the shape of the intubation tip,and the transient length was Single tip>Double sharp>Flat head,the transient length difference of the penetration process under the same working condition is mainly caused by the accumulation of foaming materials.