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Manufacturing and quality assurance of lightweight parts in mass production

Kroll L., Czech A., Wallasch R.

Journal of Machine Engineering

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2018

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Vol. 18, No. 3

42--55

EN

Production-related preliminary damage and residual stresses have significant effects on the functions and the damage development in fiber composite components. For this reason, it is important, especially for the safety-relevant components, to check each item. This task becomes a challenge in the context of serial production, with its growing importance in the field of lightweight components. The demand for continuous-reinforced thermoplastic composites increases in various industrial areas. According to this, an innovative Continuous Orbital Winding (COW) process was carried out within the framework of the Federal Cluster of Excellence EXC 1075 “MERGE Technologies for Multifunctional Lightweight Structures”. COW is aiming for mass-production-suited processing of special semi-finished fiber reinforced thermoplastic materials. This resource-efficient and function-integrated manufacturing process contains a combination of thermoplastic tape-winding with automated thermoplastic tape-laying technology. The process has a modular concept, which allows implementing other special applications and technologies, e.g. integration of different sensor types and high-speed automated quality inspection. The results show how to control quality and improve the stability of the COW process for large-scale production. This was realized by developing concepts of a fully integrated quality-testing unit for automatic damage assessment of composite structures. For this purpose, the components produced in the COW method have been examined for imperfections. This was performed based on obtained results of non-destructive or destructive materials testing.

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Choosing a proper method for strengthening WPC beams with grooving method using SWARA-EDAS

Chini Mahdi, Arefi Lale Shahid, Zolfani Hashemkhani Sarfaraz, Ustinovicius Leonas

Archives of Civil Engineering

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2018

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Vol. 64, nr 4/I

161--174

EN

Wood plastic composite (WPC) is a lightweight material, resistant against corrosion and damage, with recyclability of consuming materials. These materials usually used in marine structures frequently due to their unique features. In order to strengthen beams made by this material, usually Fibre-reinforced plastic (FRP) sheets are used, and one of the fracture modes in these beams is debonding of FRP sheet from the surface of the beams. To deal with this problem some grooves are used in the surface of the beam to improve the contact surface. The grooves include longitudinal, transverse and diagonal grooves. The main goal of this study is to assess different grooving methods in WPC-FRP beams. In this regard, primarily criteria (improving resistance, performance speed, performance complexity, performance costs, displacement and absorbing energy) were determined through interviews with experts in this field in order to assess the beams. Then, SWARA method employed to evaluate criteria with a policy based perspective and finally EDAS method applied for evaluating related alternatives. Based on obtained results, the longitudinal groove method is the best way of strengthening WPC beams to prevent debonding.

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Remaining strength in glass/polyester laminated composites subjected to ballistic impact

Barcikowski M.

Kompozyty

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2009

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R. 9, nr 3

271-275

EN

Fibre-reinforced plastics (FRP) are susceptible to damage resulting from impacts, even non-penetrating ones. This damage, even without outright destruction, may lead to reduction of fibre-reinforced plastics strength and static load-bearing abilities. This paper presents the results of three-point flexural tests on glass fibre/polyester composites after non-penetrating ballistic impact, where the word "ballistic" refers to a high-speed free-flying impactor (projectile). This is a continuation of previous studies, during which the extent of damage in glass/polyester composites after non-penetrating ballistic impact was evaluated. Materials used in the study were laminated composites produced via the Resin Transfer Moulding (RTM) technology. This laminates were produced using Polimal 1094 AWTP-1 unsaturated polyester resin and E-glass reinforcement in the form of multiple perpendicular layers of chopped-strand mats, continuous-filament mats, twisted-yarn fabrics and woven rovings. Composites with varying thickness, number of layers and fibre content were produced. The impactor is a free-flying 3 g steel ball propelled from a gas gun. Two striking velocities were tested - 60 and 70 m/s, producing impact energies of 5.4 and 7.35 J accordingly. After the impact, the extent of damage in samples (100x100 mm square plates) was evaluated through digital image analysis. The as-impacted samples were then subjected to three-point bending under set conditions. The results were compared to the results of identical examination of undamaged samples and the reduction in mechanical properties was determined. In all cases, the reduction in strength and load-at-break value was noticed. Thicker, more reinforced laminates show lower loss of mechanical properties, than thinner ones. Difference between strength and load-at-break approach for load-bearing abilities reduction was discussed, and the conclusion is that the latter is preferred to the former in laminated composites due to high thickness dependence of strength. Comparing reinforcement types, continuous-filament mat is superior to chopped-strand mat and woven-rovings. Tightly woven twisted-yarn fabric compares favourably to the woven rovings.

PL

Tworzywa sztuczne wzmocnione włóknami (FRP - Fibre Reinforced Plastics) są wrażliwe na uszkodzenia w wyniku udarów, nawet niepenetrujących. Uszkodzenia te, nawet gdy nie wystąpi całkowite zniszczenie, mogą prowadzić do znacznego obniżenia wytrzymałości i zdolności do przenoszenia obciążeń przez kompozyty wzmocnione włóknami. Artykuł przedstawia wyniki prób trzypunktowego zginania kompozytów poliestrowo-szklanych po niepenetrujących udarach balistycznych, gdzie słowo "balistycznych" odnosi się do szybko lecącego, swobodnego impaktora (pocisku). Artykuł ten jest kontynuacją wyników wcześniejszych badań, w których określono rozległość uszkodzeń w kompozytach poliestrowo-szklanych po niepenetrującym udarze balistycznym. Materiały użyte do niniejszych badań to warstwowe kompozyty poliestrowo-szklane wykonane techniką RTM (Resin Transfer Moulding). Laminaty te wytworzono z wykorzystaniem nienasyconej żywicy poliestrowej Polimal 1094 AWTP-1 i wzmocnienia z włókna szklanego typu E w postaci wielu prostopadłych warstw mat z włókien ciętych, mat z włókien ciągłych, tkanin z jedwabiu szklanego oraz plecionek rowingowych. Wykonano kompozyty o zróżnicowanej grubości, liczbie warstw i zawartości wzmocnienia. Impaktorem jest swobodnie lecąca stalowa kulka o masie 3 g rozpędzona przy użyciu działa gazowego. Próby przeprowadzono przy dwóch różnych prędkościach - 60 i 70 m/s, uzyskując przy tym energie udaru wynoszące, odpowiednio, 5,4 i 7,35 J. Po udarze rozmiary pola uszkodzeń próbek (kwadratowych płytek o wymiarach 100x100 mm) zostały zmierzone za pomocą cyfrowej analizy obrazu. Próbki w takiej samej formie, w jakiej zostały poddane udarowi, poddane zostały 3-punktowemu zginaniu w ustalonych warunkach. Rezultaty badania zginającego zostały porównane z wynikami uzyskanymi dla próbek nieuszkodzonych. Zaobserwowano pogorszenie wytrzymałości i obciążenia przy złamaniu w porównaniu z próbkami nieuszkodzonymi. Różnice pomiędzy podejściem od strony wytrzymałości a podejściem od strony obciążenia krytycznego jako parametrami opisującymi zdolność do przenoszenia obciążeń zostało przedyskutowane. Wzmocnienie w postaci mat z włókien ciągłych i gęsto tkanych tkanin z jedwabiu szklanego wypadają korzystnie w porównaniu z matami włókien ciętych i luźnymi plecionkami rowingowymi.