He Yadong

Experimental investigation of bulge forming of plastic branch pipe

Abstract Bulge forming (BF) processes as a metal working operation has received comprehensive investigation. The process and its products have been widely used in many areas. However, there are few papers published to deal with plastic BF (the application of BF technique to polymer processing, PBF). Compared to conventional polymer processing such as extrusion, injection moulding and blow moulding processes, the PBF process is relatively new, and therefore, there is no extensive knowledge base for tool and process design. This paper reviews the progress and features of the BF process and discusses the feasibility and necessity of PBF. In addition, the relationship between process variables and achievable part geometry and mechanical performance are investigated.

Modeling and experimental characterization of power-law fluids impregnation behavior in fabric during compression molding:

It is proposed that an impregnation model can predict the porosity of composites for power-law fluids impregnation in fabric. The impregnation model takes the material properties and fabric characteristic dimensions into account. In order to verify the model, glass fabric reinforced polypropylene (PP) composites are fabricated by using compression molding procedure. The impregnation model is validated by a series of comprehensive experiments, and the experimental results are perfectly consistent with the impregnation model’s value. The impregnation process is studied respectively through the model and the experiment. The results of it have shown that the impregnation time can indeed be shortened for compression molding procedure by increasing the processing temperature or increasing the applied pressure.