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Ibraimova U.B.

PhD, M. Auezov South Kazakhstan University, Department of Architecture and Urban Planning

Experimental evaluation of the thermophysical performance of an adaptive composite wall system under dynamic climatic conditions

https://doi.org/10.58224/2618-7183-2026-9-1-8
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Abstract
In the sharply continental and hot climate of Kazakhstan, improving building energy efficiency requires adaptive composite envelope systems capable of dynamically responding to external thermal loads. This study provides experimental validation of a newly developed adaptive energy-efficient wall assembly with alternating air channels and a radiant barrier, previously proposed and numerically investigated by the authors. The experiments were conducted in a climatic chamber using a full-scale 3×3 m wall fragment under two operating modes: cold conditions (–14.3 °C) and hot conditions (+26.4 °C with exterior cladding heated up to +46 °C). Interlayer temperatures, heat flux density, and thermal bridging in the bracket zone were measured, and both calculated and effective thermal transmittance resistance values were determined in accordance with regulatory requirements. The experimental results demonstrated strong agreement with numerical simulations: deviations in interlayer temperatures did not exceed 3-7%, while heat flux density differed by 6-9%. The wall configuration Scheme 3/50/75/50 exhibited pronounced adaptive behavior; switching to the ventilation mode during the hot period reduced heat flux density by up to 14% and decreased the temperature gradient within the air channel by an average of 3-5 °C. Under cold conditions, the system increased thermal resistance by up to 18% compared with assemblies without a reflective layer. The obtained effective thermal resistance values comply with the building standards of the Republic of Kazakhstan and confirm the energy efficiency of the wall system for operation in extreme climates. Overall, the experimental validation confirms the reliability of the model and the high practical applicability of the adaptive wall technology. The findings provide a scientifically grounded basis for the development of façade design standards optimized for Central Asian climates and demonstrate the potential for implementation in both new construction and retrofit projects.
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Analysis of the influence of temperature loads on the stress-strain state of a pre-stressed cylindrical shell

https://doi.org/10.58224/2618-7183-2025-8-4-5
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Abstract
The progressiveness of the idea of prestressing consists, on the one hand, in the possibility to regulate the stress state in accordance with the peculiarity of the structure operation, and on the other hand, in the expansion of the economically advantageous range of application of high- and high-strength steels. Such strengthening is also relevant for cylindrical shells, the throughput or storage volumes of which are directly proportional to the operating pressure. The most effective type of prestressing in this case is considered to be winding on the shell body at an angle to the longitudinal axis or in the annular direction without tilting the high-strength profile. In this regard, in this work, a theoretical study of the influence of temperature loads on the stress state of the combined shell was carried out. As a result of the study, an analytical evaluation method was developed that takes into account the mechanical, geometric values of the wall and wrapping material, as well as the parameters of the prestress, taking into account temperature effects. The developed method also found that the established ring stresses in the shell wall increase with an increase in the temperature gradient, and the stresses in the wrapping decrease. At a temperature gradient of 70°C, the ring stresses increased by 1.8 times, and the stresses in the wrapping decreased by 1.3 times. At the same time, the change in operating temperature has a noticeable effect on the distribution of stresses in the wall of the shell and wrapping. Thus, calculations of a main pipeline pre-stressed with steel wire showed that at a temperature gradient of ΔΤ=30°C, the achieved level of prestressing can decrease by 10-12% compared to the initial one, and at ΔΤ=50°C, the pre-stressed wrapping does not affect the stress state of the shell wall. The obtained results of the study indicate that, taking into account the temperature loads on the structure, it is possible to adopt the necessary design parameters for further design of steel shells even more accurately.
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