The current work studied the physical modification effects of non-covalent surfactant on the carbon-particle-filled nanocomposite. The selected surfactant named Triton™ X-100 was able to introduce the steric repelling force between the epoxy matrix and carbon fillers with the help of beneficial functional groups, improving their dispersibility and while maintaining the intrinsic conductivity of carbon particles. Subsequent results further demonstrated that the physically modified carbon nanotubes, together with graphene nanoplates, constructed an effective particulate network within the epoxy matrix, which simultaneously provided mechanical reinforcement and conductive improvement to the hybrid nanocomposite system. For example, the hybrid nanocomposite showed maximum enhancements of ~75.1% and ~82.5% for the quasi-static mode-I critical-stress-intensity factor and dynamic compressive strength, respectively, as compared to the neat epoxy counterpart. Additionally, the fine dispersion of modified fillers as a double-edged sword adversely influenced the electrical conductivity of the hybrid nanocomposite because of the decreased contact probability among particles. Even so, by adjusting the modified filler ratio, the conductivity of the hybrid nanocomposite went up to the maximum level of ~10⁻¹–10⁰ S/cm, endowing itself with excellent electro-thermal behavior.

Direct numerical simulation (DNS) of a hypersonic compressible flow over a blunt wedge with fast acoustic disturbances in freestream is performed. The receptivity characteristics of boundary layer to freestream pulse acoustic disturbances are numerically investigated at Mach 6, and the frequency effects of freestream pulse wave on boundary layer receptivity are discussed. Results show that there are several main disturbance mode clusters in boundary layer under acoustic pulse wave, and the number of main disturbance clusters decreases along the streamwise. As disturbance wave propagates from upstream to downstream direction, the component of the modes below fundamental frequency decreases, and the component of the modes above second harmonic components increases quickly in general. There are competition and disturbance energy transfer between different boundary layer modes. The nose boundary layer is dominated by the nearby mode of fundamental frequency. The number of the main disturbance mode clusters decreases as the freestream disturbance frequency increases. The frequency range with larger growth narrows along the streamwise. In general, the amplitudes of both fundamental mode and harmonics become larger with the decreasing of freestream disturbance frequency. High frequency freestream disturbance accelerates the decay of disturbance wave in downstream boundary layer.

An unsteady hypersonic blunt wedge flowfield under freestream slow acoustic wave is solved by direct numerical simulation (DNS), and the receptivity characteristics of the boundary layer under slow acoustic disturbance with different amplitudes are analyzed. Results show that slow acoustic wave in the freestream not only has a significant effect on the aerothermodynamics characteristics of hypersonic flowfield and boundary layer, but also on the bow shock characteristics. It shows that the maximum amplitudes of the disturbance modes in the boundary layer are positively correlated with the disturbance amplitude of the freestream. The bigger the amplitude of the freestream disturbance gets, the earlier the high-frequency disturbance mode exists, and the stronger the high frequency interference is. The larger amplitude of freestream disturbance wave can accelerate the generation of the higher order harmonic modes in boundary layer. Furthermore, the transformation position and the times of the dominant mode in the boundary layer differ under various amplitude of freestream disturbance, and compared with the smaller amplitude’s slow acoustic disturbance in the freestream, the larger amplitude disturbance can accelerate the first transformation of the dominant mode in boundary layer, and also delay its second transformation.

To explore the effect of optical media on digital image correlation measurement, the experiments of digital image correlation measurement under different optical media conditions were carried out. By analyzing the speckle images non-special optical path medium, common ordinary glass medium and quartz glass medium in the optical path, the effect of medium change in the optical path on digital image correlation measurement is discussed. The results show that the effect of different optical media on the accuracy of digital image correlation measurement is different, and the effect of optical media on absolute displacement measurement is much greater than that of rigid body displacement measurement. The effect of optical medium on different measuring areas is also different. The effect of quartz glass state on strain measurement is greater than that of ordinary glass. The effect of optical medium on the measurement of vertical optical axis displacement is much less than that of optical axis displacement measurement. Whether ordinary glass or quartz glass is added, the measurement error of camera optical axis direction is much larger than that of vertical optical axis direction; the stability of DIC displacement measurement in different optical path media is in turn ordinary glass medium, quartz glass medium and non-special optical path medium.

A hypersonic flow field over a blunt wedge with or without roughness is simulated by a direct numerical simulation method. The effect of isolated and distributed roughnesses on the steady and unsteady hypersonic flow field and boundary layer is analyzed. The shape of roughness is controlled by cubic polynomial. The evolution of disturbance waves caused by slow acoustic wave in the boundary layer is investigated by fast Fourier spectrum analysis. The results show that there is a great influence of roughness on the evolution of disturbance waves in the hypersonic boundary layer. The disturbance waves are promoted in the upstream-half region of roughness while suppressed in the downstream-half region of roughness. There is always a mode competition among different modes both in the temporal domain and in the frequency domain in the boundary layer, and mode competition is affected by roughness. The location of the dominant mode which is changed to a second-order harmonic mode from the fundamental mode moves upstream. The vortices caused by roughness also impact the evolution of disturbance waves in the boundary layer. The fundamental mode is suppressed in the vortex region while other harmonic modes are promoted.

Motion load-bearing structures are widely used in aerospace and marine heavy industries, while the means to measure the deformation of kinematic structures are limited. In response to some shortcomings of the current motion structure deformation measurement methods, this paper proposes a large-field-of-view, high-precision, and universal kinematic structure deformation measurement method based on dynamic following and dynamic vision measurement technologies, and introduces its principle, measurement steps and measurement considerations in detail. Moreover, the effect of acceleration on the highly stable structure in the dynamic following module was evaluated by finite element software. The results show that the acceleration has a great influence on the overall deformation of the high stability structure, but its influence on the measurement accuracy is limited.