JONES, P. Porovnání charakteristik předimpregnovaných a konvenčních laminátů s uhlíkovými vlákny [online]. Brno: Vysoké učení technické v Brně. Fakulta strojního inženýrství. 2023.

Posudek vedoucího

Katrňák, Tomáš

The bachelor´s thesis is focused on a complex comparison of mechanical and technological characteristics between pre-impregnated and conventional carbon fibre epoxy laminates and overview of price and availability on market. The composite types, a carbon fibre tow manufacturing process and a fabric weaving process are clearly described in initial chapters. The overview of laminate manufacturing is correctly divided according to thermoset and thermoplastic technologies in chapter 4. The carbon fibre prepreg and the wet lay-up manufacturing processes are specified in the following chapter with illustrative figures for explanation of the technologies. The detail presentation of parameters of manufacturing and curing processes of both technologies is done for contemporary materials available on market. More graphs and parameters of prepreg curing cycle in autoclave and oven could be listed there. The very important overview of prepreg storage conditions are provided in chapter 6.3.The overview of contemporary prepreg and conventional carbon fibre epoxy laminates is described very well and enriched with new technologies for part adhesion improvements and a practical guide for prepreg data finding. The part of availability and prices on market includes many practical information of roll and bobbin specifications and prices are recalculated for the direct comparison of price in USD per uniform area in figure 45. The important chapter of this thesis is the evaluation of mechanical characteristics of prepreg and conventional laminates. First, mechanical parameters of outdated and contemporary CFRP laminates are compared. The strength and Young modulus in both directions also for both loading types in tension and compression are contained in this comparison table in figure 38. The values were recalculated for the identical 60% of fibre volume fraction and presented in Appendix A1. Following direct comparisons of mechanical characteristics between pre-impregnated and conventional CFRP laminates are presented in Appendix A2. Only the logical arrangement of thesis should be changed. The chapter 7 with the general overview of prepreg and conventional CFRP should be placed before the detail technological parameters. And price information in subchapter 8.2 should be moved into the previous chapter. This thesis is complex, practical and fulfills the objectives, therefore I can recommend it for the defense at the final state exam.

Posudek oponenta

Juračka, Jaroslav

The presented thesis offers an insight into the issue of carbon fiber composite production. The student performed a status search as there was required by the assignment and familiarized himself with the topic. According to the assignment, he evaluated production technologies and described their advantages and disadvantages, compared prepreg technology and classic wet-layup technology, and described curing processes. He tried also to compare the achieved material characteristics, to compare prices with availability on the market. The thesis should be evaluated as successful. The part of the comparison of material characteristics and price is weaker, when it would be more appropriate to apply the comparison to the selected structural part. Tables would be more suitable for clarity of comparison. Furthermore, minor differences in terminology like cloth/fabric, etc. are there.

eVSKP id 149276