The rheological properties of HTPB mixed with boron (B) or agglomerated boron (TB) were investigated to explore the effect of the impurities of boron on the processing of propellant. The phase structure, morphology, and acidity of each sample were characterized by XRD, SEM and pH, respectively. The results show that rheological property of B/HTPB can be significantly improved by agglomerating boron with binder. Time has little effect on the viscosity of TB/HTPB while that of B/HTPB is a strong function of time. The viscosity of TB/HTPB decreases when the temperature increases from 303K to 343K, while that of B/HTPB decreases from 303K to 323K and then increases sharply after 323K. After agglomerating with binder, theTonsetof boron reduces from 1056K to 954K andTpdrops from 1076K to 998K. Compared with B2, the weight gain and oxidation degree of TB2 increases by 27% and 8.5%, respectively.
TWB and its forming technology play important role in lightweight manufacturing for the automobile parts. The weld-line movement during TWB forming process affects the product quality greatly. In this paper, two main influence factors of the movement, BHF and the blank thickness at the both sides of the weld-line, were studied by both the experiments and finite element simulation. The results showed that BHF has significant impact on the weld-line movement, especially when the thickness difference of the blanks in TWB is beyond a certain range. Besides, suitable BHF and thickness of the blanks can not only control the weld-line movement, but also improve the formability of TWB.
A method to evaluate the rheological properties of low density polyethylene (LDPE) using torque rheometer was developed and the parameter of Power rate model were obtained by fitting balance torque and balance temperature. The rheological parameters of polymer melts were evaluated on the basis of previous equation by introducing the apparent filling degree in torque rheometer, the results show the temperature compensated torque (Mtc) increase from 5.685 Nm to 6.972 Nm, while apparent filling degree change from 0.65 to 0.85 at the rotor speed of 29.98 rpm. TheMtcalso increase from 2,900 Nm to 3.528 Nm and increase by 0.628 Nm at the rotor speed of 4.985 rpm, while it increase by 1.287 Nm from 5.685 Nm to 6.972 Nm at the rotor speed of 29.99 rpm, which means the higher the rotor speed, the more influence on the torque. The other relative rheological parameters, such as the activation energy (ΔE), the Non-Newton (n), etc., calculated in this model, indicate the effect of apparent filling degree on the polymer melting rheology. The calculated values were compared with those derived from capillary rheolometer, the results show the apparent viscosity decrease with the increase shear rate in exponential function, the change rules of apparent viscosity are good agreement from two kinds test methods.
Drive line is the surface defect on the automotive panel. In order to investigate the causes and control methods of the drive line, the box-shaped part with curved bottom was designed based on the shape characteristics of automobile panel. Then this part was taken as an experimental model to analyze the causes and forming process of the drive line on its surface. Finally, influencing laws on the drive line from the draw bead, the important forming process parameter, were obtained by the experiments. The results showed that the draw bead has great impact on the drive line. Different setting ways of the draw beads can make good control for the formation, displacement and its direction of the drive line. Besides, it is an important way for setting the draw beads properly to prevent the stamping parts from the formation of the drive line.
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