Optimal Design and Experimental Verification of Ultrasonic Cutting Horn for Ceramic Composite Material

We developed and optimized a block-type ultrasonic horn that can be used for cutting hard materials. The proposed block-type sonotrode consists of an aluminum horn and a tungsten carbide blade to increase the cutting of hard materials. We designed an initial ultrasonic block horn that has double slots and an exponential stepped profile. We developed a finite element model of the initial model and analyzed the characteristics of natural frequency and displacement. We formulated a DOE table and response surface to perform sensitivity analysis and analyze the correlation between the design variables and characteristics of the proposed block horn. The optimal ultrasonic block horn was derived via a multi-objective optimal design problem to maximize the amplitude uniformity of the proposed horn and frequency separation. We fabricated the optimal block horn and verified it experimentally. An ultrasonic cutting experiment was conducted to find the ultrasonic cutting force with hard ceramic composite materials. A cutting test with a conventional cutting machine under the same condition was also conducted to compare the cutting force. The proposed optimal ultrasonic cutter requires 70% less cutting force than the conventional cutter to cut a ceramic composite material and the cutting surface with the application of the proposed optimal ultrasonic cutter is much cleaner with no crack and delamination than that with the application of the conventional cutter.

Research of the behavior of ceramic composite material based on ZrO2 fibers in the field of concentrated solar radiation

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OXIDE FIBER COATED WITH SILICON CARBIDE FOR PRODUCING COMPOSITE MATERIALS

The article presents the results of an experiment on the application of a silicon carbide coating on an alumina fiber and studies the properties of the resulting coated fibers. The purpose of applying a barrier coating to the fibers is to protect the fiber from degradation during the manufacturing of a ceramic composite material. The paper gives the characteristics of barrier coatings, such as thickness, continuity, structure, thermal and thermo-oxidative properties. The obtained data will be useful in the development of new types of ceramic composite materials reinforced with fibers.

An Analysis of Combined Radiation-Conductive Heat Transfer During the Destruction of Porous Carbon-Ceramic Composite Material of the Thermal Protection Shield

Carbon-ceramic composites are considered promising materials to be used in thermal protection shields of innovative descent vehicles that are currently being designed. The development of thermal shield material requires modelling its thermal-phase state under operational conditions. In this paper, physical and mathematical models are proposed for analysis of the destruction and radiation-conductive heat transfer in a porous carbon-ceramic composite material consisting of carbon fibres covered by silicon carbide. The models take into account all main physical and chemical processes of heating up and thermo-chemical destruction. A software package DMA based on the finite element method was developed, and modelling of heating up and destruction of the material was conducted. It was established that when the temperature was above 800 °С, the contribution of the radiation heat exchange became considerable. A comparison of the surface microstructures obtained through modelling and gas-dynamic testing in a plasmatron facility showed their qualitative agreement, while the mass loss did not exceed 16%.