In the present paper, the force‐fit connection of discrete ceramic components by means of geometrically interlocking surfaces is studied. These surfaces possess a concavo‐convex topology permitting assembly of structures in which each individual element is kinematically locked by its neighbors. Such structures have a tuneable bending stiffness, allow for large deformations and are tolerant to missing or destroyed elements. These properties of topologically interlocked structures make them particularly attractive in construction with brittle materials. The elements used were produced by freeze gelation of ceramic slurries, leading to near net shape with the coefficient of shrinkage below 3%. It is shown that planar assemblies of interlocked ceramic elements can withstand flexural deflections up to a ten‐fold of those a solid plate from the same material can sustain. The response of these structures to concentrated load can be divided into an elastic and a quasi‐plastic, i.e., irreversible, part. After the point of maximum load, the interlocked structures investigated were still able to withstand further deformation, whereas solid plates showed brittle failure.

We present an interesting processing route for obtaining alumina/mullite‐based ceramics with controlled porosity and airflow resistance leading to promising microstructures for application as sound absorbers. The use of ceramic materials aims for potential applications where high temperatures or corrosive atmospheres are predominant, e.g., in combustion chambers of gas turbines. For the production of the porous ceramics we combined freeze gelation and sacrificial templating processes to produce near‐net‐shaped parts with low shrinkage (<3%) based on environmental‐friendly and low cost conditions. The obtained microstructure presents a bimodal pore size distribution, with small pores derived from the freeze gelation process (~30 μm) connecting large pores (2–5 mm diameter) originated from the expanded polystyrene template particles. These connections, called “windows” in this study, show a significant impact on the sound absorption properties, allowing the pressure diffusion effect to take place, resulting in a significant improvement of the sound absorption coefficient. By varying the template particle content and the slurry solid content, it is possible to control the sound absorption behavior at different frequencies of the open‐celled ceramics. These ceramics feature a high open porosity, from 77% to 82%, combined with sufficient compressive strength ranging from 0.27 to 0.68 MPa and sound absorption coefficients of 0.30–0.99, representing a highly promising combination of properties for noise control and reduction at corrosive environments and high temperatures.

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This paper discusses the potential of using porous ceramic lining as insulating material in combustion chambers with respect to their sound absorbent ability to suppress thermoacoustic instabilities. For this purpose a combustion chamber test rig was developed and different types of ceramic linings were tested. The examined range of power was between 40 and 250 kW and the air-propane equivalence ratio was between 1.2 and 2.0. The overall sound pressure level and frequency domain of a lean premixed swirl stabilized and piloted burner are presented. The resonance frequencies and sound pressure levels are obtained and compared for the different combustion chamber linings. The results show a significant decrease in overall sound pressure level by up to 23.5 dB for sound absorbent lining in comparison to the common sound reflecting combustion chamber lining. In summary, sound absorbent ceramic combustion chamber lining can contribute to improve the stability of lean premixed gas turbines.