Wyniki wyszukiwania - BazTech

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Carbon Fibre Reinforced Polymer Fatigue Strengthening of Old Steel Material

Kowal Maciej, Pietras Daniel

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 1

197--209

EN

This paper reports the experimental results of a study investigating the effect of CFRP strengthening of metallic structures for increasing fatigue life. In the study, samples made form puddled steel and mild S235 grade steel strengthened with CFRP strips were examined. Samples were subjected to tensile fatigue loading with a stress ratio R of 0.115 and 0.130 (mild steel samples) and 0.13/1.25/0.15/1.07 (puddled steel samples). A total of 9 samples with CFRP/steel single overlap joints and 20 reference specimens were tested to determine their fatigue life and failure modes. Normal modulus CFRP strips with one cross section (20 x 1.4 mm) were used in this study. Laboratory test results showed that CFRP strengthening has visible effect on the fatigue life of the steel. The application of adhesively bonded CFRP laminates significantly prolongs fatigue life of the specimens. The increase in fatigue life of the steel samples strengthened with CFRP strips was 2 to 16 times (for mild steel) and 11.6 to 34.8 times (for puddled steel).

2

Elimination of inconsistencies in the process of expanding the fleet of electric buses

Szczucka-Lasota Bożena, Węgrzyn Tomasz, Kowal Maciej, Cybulko Piotr

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2022

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z. 158

599--606

EN

Purpose: The aim of the work is to present selected research results of the first stage of work, the so-called pre-design research related to the implementation of electric vehicles into the company's fleet. Design/methodology/approach: the article presents inconsistencies and problems related to the use of electric buses as well as problems related to point infrastructure. The results of the research were obtained from the observations of the analyzed transport processes, the process of fleet management, from interviews with employees, as well as from the analysis of documentation and comparison of records with the actual state. Findings: The results confirm that the effective elimination of nonconformities leads to the improvement of the process quality and the reduction of costs related to vehicle breakdowns. Research limitations/implications: The research indicates the need for continuous improvement of the process of using electric vehicles. Validation studies have confirmed that it is impossible to eliminate all problems, therefore the process should be constantly improved. Originality/value. The article indicates the need to amend the subsequent projects and the current methodology of the procedure.

3

Effect of Adhesive Joint End Shapes on the Ultimate Load-Bearing Capacity of Carbon Fibre-Reinforced Polymer/Steel Bonded Joints

Kowal Maciej

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 4

299--310

EN

This paper reports the experimental results of a study investigating the effect of adhesive joint end shapes on the load-bearing capacity of carbon fibre-reinforce polymer (CFRP) and steel bonded joints. In the study, samples with new proprietary types of CFRP strip ends were examined. All samples were subjected to tensile quasi-static loading with a load rate of 1.5 mm/min. A total of 60 samples with CFRP/steel single overlap joints were tested to determine their ultimate load-bearing capacity, effective bond length and failure modes for the above variables. 8 joint end shapes of normal CFRP modulus with three lengths of CFRP overlap and one CFRP cross section (20 x 1.4 mm) were used in this study. Laboratory test results showed that joint end shape has visible effect on the load capacity of the CFRP/steel bonded joints. The load-bearing capacity of the samples with a regular joint end was up to 28 % lower than that of the samples with a plan-shaped end and 30 % lower than that of the samples with a chamfered end with adhesive outflow. The differences in the results decreased with increase in joint end length towards the effective end length.