The work concerns the monitoring of the technical condition of metro trains. For this purpose, a vibration monitoring system installed in buildings in the vicinity of the underground is used. Based on measured vibrations buildings, the identification of technical condition in metro trains is conducted. The results of measurements from the system are also used to assess the impact of vibrations on people staying in buildings through the WODL ratio. Exceeding the assumed levels of the WODL ratio is the basis for repairing trains by turning wheels. Statistical analysis of the data was implemented and trends for particular time periods of measurements were shown. With the entered monitoring system and the introduced WODL index thresholds, it is possible to better plan the costs associated with the repair and replacement of wheels of rolling stock, where there are large values of radial runout. According to the introduced monitoring procedure, the number of complaints from residents decreased and the comfort of their lives improved.
In this article, the possibility and the pertinence of using 3D printed polymeric materials for models in modal tests on shaking tables were recognized. Four stages of the research have been linked: The material properties investigation, the field experiment on the modal properties of the reinforced concrete chimney (a prototype), the shaking table tests on the modal properties of the 3D printed polymer model of the chimney, scaled according to the similarity criteria, and the numerical calculations of the FE model of the 3D printed mockup. First, the investigation of the properties of 3D printed polymer materials revealed that the direction of lamination had no significant effect on the modulus of elasticity of the material. This is a great benefit, especially when printing models of tall structures, such as chimneys, which for technical reasons could only be printed in a spiral manner with the horizontal direction of lamination. The investigation also proved that the yield strength depended on the direction of the lamination of the specimens. Next, the natural frequencies of the chimney, assessed through the field experiment and the shaking table tests were compared and showed good compatibility. This is a substantial argument demonstrating the pertinence of using 3D printed polymer materials to create models for shaking table tests. Finally, the finite element model of the 3D printed polymer mockup was completed. Modal properties obtained numerically and obtained from the shaking table test also indicated good agreement. The presented study may be supportive in answering the question of whether traditional models (made of the same material as prototypes) used in shaking table tests are still the best solution, or whether innovative 3D printed polymer models can be a better choice, in regard to the assessment of the modal properties and the dynamic performance of structures.
Historic buildings constitute a specific group of buildings where the possibilities of improving energy efficiency and comfort are significantly limited because of the existing construction features and heritage values. Each building has a different history so the scope of renovation and/or retrofitting must be determined individually for each building. This article presents the methodology of measurement and diagnosis of features of particular importance for energy performance and comfort improvements, based on the example of a historic masonry building located in southern Poland. The first research question was which of the comfort conditions have been exceeded according to measurements. The second issue concerned the necessary extension of the basic determinants of comfort, beyond measurable qualities. A multi-faceted approach to the comfort assessment is proposed, including qualitative research that applies the additional criterion of aesthetic comfort. During the case study diagnosis, the acceptable level was exceeded in thermal, acoustic and aesthetic comfort. The first two may be addressed by optimized technical measures whilst the latter through a research-through-design that addresses the complex relationship between the perceiver and what the environment affords. The solution reflects the need to meet demands for retrofits that are energy-efficient and aesthetically pleasing while minimizing any negative impacts on the heritage and the environment.
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