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Virtual simulation is very important for engineering application. Traditional simulation based on DELMIA platform has some shortcomings, such as limited capability of detailed observation, low precision and time-consuming. VR system simulation can effectively solve these problems. However, in engineering applications, the large model simulation in VR system cannot meet the real-time requirements, and collision detection is often slow or even collapsed. To solve this problem, this paper proposes a dual-model approach for engineering collision detection in the CAVE environment: a display model and a collision detection model are established respectively. The display model contains a large model, and the collision detection model contains a manikin and the hidden large model. For visual rendering, the display model uses caching strategy, and the collision detection model uses real-time strategy. The two sets of models are combined and presented in CAVE. Because the dual-model approach separates the visual rendering of the large model from the collision detection calculation, the large model in the collision detection model can be lightweight, or the area of interest can be selected for the collision detection calculation. Experiments show that the dual-model approach can effectively guarantee the real-time performance of visual display and collision detection, and provides a complete solution for engineering collision detection using the CAVE system, which can be applied in the fields of industrial virtual maintenance, assembly, and pre-design evaluation.

Based on self-focusing and uniform dispersion principle, a novel mica uniform dispersion crystal spectrograph (UDCS) was developed, whose linear dispersion was designed to be constant. An aluminum wire-array imploding experiment was performed at “Yang” accelerator and K-shell emission spectra were measured to investigate Z-pinch aluminum plasma characteristics by using the UDCS. The linear dispersion deduced from obtained spectra with linear fitting was in good agreement with the theoretical value. By using the collisional–radiative equilibrium (CRE) model, the intensity ratios of Ly-α/He-α line and Ly-β/He-e were given as a function of electron temperature. The measured intensity ratios were compared to the computed ones and the electron temperatures were estimated to be 512 eV and 489 eV. The slope of the free-bound X-ray continuum provides a model-independent diagnostic of the core electron temperature which was around 1215 eV for this implosion. Analysis of Z-pinch radial temperature gradient shows that the temperature decreases sharply near the core and slowly to the shell regions. Benefiting from the UDCS providing high spectral resolution ( λ /Δ λ ∼2500), the existence of first-order Langmuir dips were observed and reliably identified in Al Ly-α and Ly-γ resonance line profiles. The relationship between the position from the line center of red Langmuir dips and electron density was studied. The electron densities deduced from these fine spectral features were 5.52×10 21 cm −3 and 4.57×10 21 cm −3 respectively, which compared well with those derived from measurements of the line shift. The ion temperature was determined from the Doppler broadening of Al He-α resonance, He-like intercombination and Li-like s, t ( n =2) satellite lines.

Based on the traditional shear-lag model, using hierarchical multi-scale approach to research the tensile strength of fiber-reinforced composite. In this method, the tensile strength of carbon fibers is described by Weibull function, and a Monte-Carlo progressive failure model is established to analyze the longitudinal tensile strength of unidirectional composite materials, and we use this model to analyze the influence of micro parameter on the macro properties of fiber-reinforced composites, such as thermal residual stress and strength of interphase. The model can be used to predict macro-performance of fiber-reinforced composites and can give a reference for composite design and optimization.

On the basis of the conformal characteristics of a logarithmic spiral crystal in a large field of view(FOV),a new type of transmission crystal analyzer used for X-ray monochromatic imaging was investigated.Compared with a reflection type of crystal analyzer,the logarithmic spiral crystal analyzer has a wider FOV for catching the monochromatic X-ray image and a simple space arrangement for achieving the same magnification.According to the diffraction theory of the crystal and the surface equation of log spiral,the imaging principles and characteristics of the transmission type logarithmic spiral crystal analyzer were researched,including the magnifications in horizontal and vertical directions as well as the FOV sizes.A logarithmic spiral analyzer with a quartz crystal was developed.Then with the proposed analyzer,the monochromatic backlighting experiment for the mesh grid with a diameter of 100 μm was carried out by taking an X-ray source of Cu target as the backlighter.The experimental results show that the FOVs of the transmission type logarithmic spiral crystal analyzer are 15.938 7 mm and 5.900 6 mm in horizontal and vertical directions,respectively.Furthermore,the spatial resolution of the analyzer is at least 30 μm under a source diameter of 110 μm.

Based on the Bragg law and imaging principle of bent crystal, the imaging properties of the monochromic backlighting system with a toroidally bent crystal were studied via ray-tracing simulations and experiments. Comparison experiments with both toroidally and spherically bent crystals using a Cr line as the backlighter were performed, showing that using toroidally bent crystal, a 2D image with the same magnifications in meridional and sagittal directions can be obtained with higher spatial resolution. Experiments with laser-produced plasmas using Mica crystal were carried out on the Shenguang II laser facility. Five laser beams were focused onto a Ti planar target producing a line at 4.75 keV as the backlighter and an image of a metal grid with size of 200 μm × 200 μm was recorded with an x-ray image plate. A spatial resolution of 40 μm was demonstrated with a magnification of 3 due to the restriction of the target chamber size. 10 μm spatial resolution might be possible if the detector can be located outside the chamber to enlarge the magnification.

The reflection type toroidally bent crystal analyzer was investigated based on the Bragg diffraction to diagnose the laser plasma X-ray. The dispersive element of crystal analyzer was mica. The bent radiuses of the crystal analyzer in meridian plane and in sagittal plane are 296 mm and 198 mm respectively, and the corresponding Bragg angle is 54°.

Characterization of the mechanical properties of carbon fibres is crucial to the design of fibre reinforced composite materials. However, little has been done due to the complexity and inaccuracy of some of the necessary tests. In order to study the compressive properties of single fibres, a direct system for single carbon fibre compressive strength was set up based on previous studies; several kind of PAN-based carbon fibres were examined at specimen gauge lengths from 20 to 150 μm using this system. It was discovered that the experimental compressive strength was constant when the length of carbon was in the range of 20~90 um; when the sample's length was beyond 90 μm, the compressive strength decreased sharply. The reason is that its deformation mode was not compressive but buckling. In order to compare with corresponding tensile behaviour, a tensile strength test was also carried out, and it was discovered that the compressive strength was about 50% of the tensile strength for single fibres.