In this paper, the current bolt axial stress measurement is investigated and summarized. Bolt transducer method is chosen to take experiments and test. The strain bolt axial stress transducer and optical fiber axial stress transducer are both developed and researched in this paper, which the craft process and experiments are explored and carried out. The testing data is obtained and transducer characteristics are calculated and analyzed.
In this paper, a large-scale composite thin-walled stiffened structure is subjected to an axial compression stability test. The stability of the structure is tested and analyzed using resistance strain gauges, digital speckle correlation and finite element methods. The analysis results were analyzed from four aspects: instability load, load strain result, load displacement result and test calculation result comparison. In this paper, the initial buckling load, load-strain bifurcation curve, buckling wave distribution characteristics of the composite thin-walled stiffened curved plate under two radius parameters, the comparison of the test deformation results and the calculation analysis results, etc. are obtained for research. The research on the stability of large-scale composite thin-walled reinforced structures provides new ideas and methods.
Digital coding-mask technique based on digital micro-mirror devices (DMD) is proposed in this paper. The fundamental rule of digital coding-mask technique is to modulate the incident light intensity by adjusting the transmittance of the units on the coding-mask. The transmittance is controlled by the apertures on the units of the coding-mask. Lohmann’s III coding method and error diffusion coding method are employed to coding mask, and wavelet transformation is used to suppress the background noise of the mask image. Real-time control on the image of the digital coding mask can be realized by loading the coded mask image to DMD, which is driven by a computer. Digital coding-mask technique gives full play of the advantages of DMD, such as real time and flexibility. In addition, the digital coding-mask technique is helpful to deal with the problem of mask aberration, which is caused by the nonlinear effect in the process of projection and exposure. This technique can also make use of optimization algorithm to suppress the background noise of the digital coding-mask images so that the quality of the relief structure of photoresist is improved.
In this paper, the aperture change of the aluminium alloy aerospace structure under real load is researched. Static experiments are carried on which is simulated the load environment of flight course. Compared with the traditional methods, through experiments results, it’s proved that 3D digital speckle correlation method has good adaptability and precision on testing aperture change, and it can satisfy measurement on non-contact,real-time 3D deformation or stress concentration. The test results of new method is compared with the traditional method.
An approach, which is used to fabricate diffractive optical elements (MOEs), is presented by applying reduction
projecting system based on digital micro-mirror device (DMD). In this paper, coding-mask is combined with DMD
which is real-time, flexible and easy for alignment. Pre-distortion according to the non-linear effect in the aerial
image and resist course can be implemented. The accumulation of exposure energy can be obtained through
modulating rotating velocity of mask graphics, and finally distribution of exposure, which is required, can be
achieved. It shows that the method is practical and feasible on the grounds of the results of MATLAB simulation and
experiments.
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