Refined Spherulites of PP Induced by Supercritical N and Graphite Nanosheet and Foaming Performance.

The isothermal crystallization properties of polypropylene/graphite nanosheet (PP/GN) nanocomposites under supercritical N were systematically studied by a self-made in situ high-pressure microscope system. The results showed that the GN caused irregular lamellar crystals to form within the spherulites due to its effect on heterogeneous nucleation. It was found that the grain growth rate exhibits a decreasing and then increasing trend with the enhancement of N pressure.

Constitutive model of 6063 aluminum alloy under the ultrasonic vibration upsetting based on Johnson-Cook model.

Establishing an accurate constitutive relation in ultrasonic vibration assisted metal forming, can provides a reliable theoretical basis for analyzing the mechanism of the ultrasonic vibration on materials. A constitutive model of 6063 aluminum alloy under the ultrasonic vibration upsetting at room temperature was constructed based on Johnson-Cook Model and experimental results. The influence of amplitude and frequency on the yield strength, hardening coefficient and exponent were analyzed quantitatively.

A nanocrystalline-amorphous mixed layer obtained by ultrasonic shot peening on pure titanium at room temperature.

A nanocrystalline-amorphous (NC-A) mixed layer was obtained by ultrasonic shot peening (USP) on pure titanium at room temperature and observed by X-ray diffraction pattern (XRD), scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM). The results showed that the amorphization percentage in the NC-A mixed layer increased continuously with the increase of the peening duration, shot diameter and sonotrode amplitude or the decrease of the peening distance. The maximum amorphization percentage achieved in this study was 44.

Effects of ultrasonic vibration on the compression of pure titanium.

The technology of ultrasonic vibration assisted plastic forming possesses a great many merits, such as reducing the deformation resistance and friction, as well as improving the surface quality of parts. In this study, the ultrasonic vibration assisted compression tests were carried out on pure titanium in order to improve its formability. The results indicating that the ultrasonic vibration had no effort on elastic deformation, and the temperature of material only increased by 6 °C after compression with applying the ultrasonic vibration.

The effects of forming parameters on conical ring rolling process.

The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established.

Biomechanical supporting effect of tantalum rods for the femoral head with various sized lesions: a finite-element analysis.

Background: Features of necrotic lesions and various interventions could affect the biomechanics of the femoral head. A three-dimensional finite-element analysis was designed to demonstrate necrotic femoral head stress changes with various sizes of necrotic lesions, and evaluate the effect of tantalum rods on preventing femoral head cracking.

Methods: Femoral computed tomography scans were used to build a normal three-dimensional finite-element femoral head model in a computer.

[Three-dimension finite element analyses of interior stress of two kinds of Replace implant].

Objective: To establish three-dimension finite element model of mandible with two kinds of Replace implant, and to study stress of implant and abutment.

Methods: The data of components of the dental implant was measured, cross section of the mandible was scanned by spiral CT and image reconstruction technique was conducted. Three-dimension finite element analysis software UG and MSC.

[Three-dimensional finite element analyses of bone surface stress of two kinds of conjunction implant].

Objective: To establish a three-dimension finite element model of mandible with two kinds of dental implant and to study the stress of implant-bone interface.

Methods: Measuring the data of the components of the dental implant and using spiral CT image reconstruction technique to scan the cross section of the mandible. Three-dimension finite element analysis software Unigraphics and MSC.