Banca de QUALIFICAÇÃO: FRANCISCO DE ASSIS DA SILVA JÚNIOR

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : FRANCISCO DE ASSIS DA SILVA JÚNIOR
DATE: 14/11/2024
TIME: 09:00
LOCAL: https://meet.google.com/bfi-bben-vrn
TITLE:

ANALYSIS OF THE BEHAVIOR OF GLASS FIBER-EPOXY COMPOSITES IMPACT WITH POLYETHYLENE-CO-METHACRYLIC ACID (EMAA) AS A REPAIR AGENT

KEY WORDS:

poly-ethylene-co-methacrylic acid (EMMA); fiberglass-epoxy; short-beam; self-repair

PAGES: 87
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUBÁREA: Mecânica dos Sólidos
SPECIALTY: Análise de Tensões
SUMMARY:

Polymeric glass-epoxy composites are widely recognized for their versatility, primarily due to their outstanding mechanical properties. However, when subjected to loads, service conditions, and environmental factors, they may develop microcracks that compromise these properties. The literature suggests that the addition of a thermally activated self-healing thermoplastic, such as polyethylene-co-methacrylic acid (EMAA), can help extend the service life of these laminates. It is worth considering the replacement of conventional glass fiber-epoxy composites with thermoset matrices by self-healing composites, especially in conditions where they demonstrate superior practical performance. Thus, with the aim of contributing to academic research, this study analyzed the influence of EMAA in glass-epoxy prepreg laminates, investigating interlaminar shear strength (ILSS), damage propagation under low-velocity impact (drop-weight type), and post-impact ILSS, comparing the mechanical properties at 0% and 10% of the self-healing agent. The tests were conducted according to ASTM D 2344M (2022) and ISO 14130 (1997) standards for ILSS, and ASTM D 7136 (2020) for drop-weight impact. Experimental results indicated that ILSS strength in samples with the self-healing agent remained practically unchanged, showing a reduction of only 3.6%, with a strength of (26.57 ± 0.37) MPa. Regarding the damage data, the samples without EMMA exhibited significant degradation of mechanical properties, with a 52.4% reduction in shear strength after 20 impacts, along with considerable damage propagation, reaching a delamination area of 1495.48 mm². In contrast, the samples with the self-healing agent showed better performance, with only a 26.2% reduction in shear strength, even after multiple impact cycles. The delamination area was drastically smaller, with values of 309.16 mm² after repair. The normalization analyses of residual strength indicated that the samples repaired with EMMA retained about 77% of the original strength, while the samples without the agent exhibited pronounced degradation. These results confirm that EMMA is effective in limiting damage propagation and restoring some of the mechanical properties of fiberglass laminates.

COMMITTEE MEMBERS:
Presidente - 1338331 - RAIMUNDO CARLOS SILVERIO FREIRE JUNIOR
Interno - 434906 - AVELINO MANUEL DA SILVA DIAS
Externa ao Programa - 2042234 - ANA PAULA CYSNE BARBOSA - UFRN