Adhesives for increasing the bonding strength of in situ manufactured metal-composite joints

2020 ◽  
pp. 095440702096575
Author(s):  
Robert Thomas ◽  
Fabian Fischer ◽  
Maik Gude
Keyword(s):  
Bonding Strength ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Storage Conditions ◽  
Mechanical Tests ◽  
Metal Composite ◽  
Scanning Calorimetry ◽  
Lap Shear ◽  
Glass Fibre Reinforced ◽  
Metallic Parts

In this present work, the potential of metallic parts, locally reinforced with a continuous glass fibre reinforced thermoset material, pre-impregnated with an epoxy matrix (prepreg), was evaluated by differential scanning calorimetry (DSC), single-lap shear tests and 3-point bending tests of a metal-composite hybrid hat profile. This technology is evaluated regarding an automotive use case, the DSC experiments in combination with moulding trials have proven curing times below 30 s for a moulding temperature of 180°C. A bonding strength of 13.5 MPa was characterized for a co-cured fibre-reinforced plastic (frp) onto a metallic joining partner. By additionally introducing an epoxy glue film as a bonding agent, which is co-cured together with the frp, the bonding strength can be increased significantly up to 25.4 MPa at the expense of the curing time. The mechanical tests on the hybrid hat profile have shown an increase of energy absorption compared with non-reinforced hat profiles. Here, also an additional glue film extends the performance regarding a co-cured plastic reinforcement without glue film. The influence of the storage conditions of the uncured prepreg materials on the mechanical performance was evaluated by a simulated physical ageing at elevated temperatures, followed by a mechanical characterization of the bonding strength and part performance. Also the effect of different testing temperatures and testing velocities on the capability of the metal-composite hybrid part is illustrated.

scholarly journals Mechanical Performance Under Various Conditions of 3D Printed Polylactide Composites With Natural Fibers

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Stanislaw Kuciel
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Natural Fibers ◽  
Crystallization Rate ◽  
Mechanical Tests ◽  
Hydrothermal Degradation ◽  
3D Printed ◽  
The Impact ◽  
Different Levels ◽  
Additive Methods

Abstract In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by additive methods were tested. The effect of type fiber, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different level of infilling result in a similar level of reduction in the properties. Composites made of PLA are more sensitive to high temperature than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Moreover, the impact strength has been improved by 50% for composites with cork particles and for other lignocellulosic composites remained at the same level as for resin.

scholarly journals Mechanical, Thermal and Microstructural Characteristic of 3D Printed Polylactide Composites with Natural Fibers: Wood, Bamboo and Cork

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Rafał Bogucki ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Elevated Temperatures ◽  
Fiber Type ◽  
Mechanical Tests ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
The Impact ◽  
Different Levels ◽  
Natural Fillers

AbstractIn the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by fused deposition modeling were tested. The effect of fiber type, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Differential scanning calorimetry were employed to analyze crystallization behavior of composite. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different levels of infilling result in a similar level of reduction in the properties. However, the addition of natural fillers resulted in a slightly lower drop than the lowered infilling rate − 40% and 50% for tensile strength, respectively. Moreover, it was found that, composites made of PLA are more sensitive to high temperatures than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Importantly, in the case of a brittle material such as PLA, the impact strength has been improved by 50% for composites with cork particles and other lignocellulosic composites remained at the same level as for resin. Generally, the thermal treatment of composites increased the degree of crystallinity of the materials, as reflected in the higher results of mechanical tests.

Assessment of mechanical strength of nano silica concrete (NSC) subjected to elevated temperatures

2019 ◽  
Vol 10 (1) ◽  
pp. 90-109 ◽  
Author(s):  
Hala Mohamed Elkady ◽  
Ahmed M. Yasien ◽  
Mohamed S. Elfeky ◽  
Mohamed E. Serag
Keyword(s):  
Elevated Temperature ◽  
Bond Strength ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Content Type ◽  
Post Exposure ◽  
Concrete Mix ◽  
Bond Strengths

Purpose This paper aims to inspect the effect of indirect elevated temperature on the mechanical performance of nano silica concrete (NSC). The effect on both compressive and bond strengths is studied. Pre- and post-exposure to elevated temperature ranges of 200 to 600°C is examined. A range covered by three percentages of 1.5, 3 and 4.5 per cent nano silica (NS) in concrete mixes is tested. Design/methodology/approach Pre-exposure mechanical tests (normal conditions – room temperature), using 3 per cent NS in the concrete mix, led to the highest increase in both compressive and bond strengths (43 per cent and 38.5 per cent, respectively), compared to the control mix without NS (based on 28-day results). It is worth noticing that adding NS to the concrete mixes does not have a significant effect on improving early-age strength. Besides, permeability tests are performed on NSC with different NS ratios. NS improved the concrete permeability for all tested percentages of NS. The maximum reduction is accompanied by the maximum percentage used (4.5 per cent NS in the NSC mix), reducing permeability to half the value of the concrete mix without NS. As for post-exposure to elevated-temperature mechanical tests, NSC with 1.5 per cent NS exhibited the lowest loss in strength owing to indirect heat exposure of 600°C; the residual compressive and bond strengths are 73 per cent and 35 per cent, respectively. Findings The dispersion technique of NS has a key role in NSC-distinguished mechanical performance with NSC having lower NS percentages. NS significantly improved bond strength. NS has a remarkable effect on elevated temperature endurance. The bond strength of NSC exposed to elevated temperatures suffered faster deterioration than compressive strength of the exposed NSC. Research limitations/implications A special scale factor needs to be investigated for the NSC. Originality/value Although a lot of effort is placed in evaluating the benefits of using nano materials in structural concrete, this paper presents one of the first outcomes of the thermal effects on concrete mixes with NS as a partial cement replacement.

Study of Processing and Properties of a few Hemp Linter Fiber Reinforced Polylactic Acids Composite Materials

2011 ◽  
Vol 332-334 ◽  
pp. 1785-1789
Author(s):  
Jia Shuang Luan ◽  
Mei Zhang ◽  
Fu Gui Zhou ◽  
Yang Wang ◽  
Gang Ma ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Mechanical Performance ◽  
Average Molecular Weight ◽  
Degradation Process ◽  
Mechanical Tests ◽  
Scanning Calorimetry ◽  
Hemp Fiber ◽  
Batch Mixing ◽  
Sample Count ◽  
Poly Ethylene

Composites of poly(L-lactide) (PLA) with hemp linter fibers, prepared by batch mixing and plasticized with poly(ethylene glycol) (PEG; weight-average molecular weight 1000 g/mol), were examined by differential scanning calorimetry, thermogravimetric analysis, and mechanical tests. The properties of samples of PLA/hemp and PLA–PEG/hemp composites were analyzed as a function of the fiber amount. The thermogravimetric analysis of the composites, carried out in air, showed that the degradation process of fiber-filled systems started earlier than that of plain PLA, independently of the presence of the plasticizer. Mechanical tests showed that the property of the composites have been enhanced increased with the hemp content. The mechanical performance high-point of composites appear with count of hemp linter fiber at 1%.(sample count of hemp fiber form 1% to 7%). Plasticization with PEG did not improve the tensile properties of the composites, but improve its break stress.

scholarly journals Relationships between the Decomposition Behaviour of Renewable Fibres and Their Reinforcing Effect in Composites Processed at High Temperatures

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4448
Author(s):  
Janez Slapnik ◽  
Thomas Lucyshyn ◽  
Gerald Pinter
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Mechanical Analysis ◽  
Fibre Reinforcement ◽  
Reinforcement Effect ◽  
Scanning Calorimetry ◽  
Melt Flow Rate ◽  
Decomposition Behaviour

Engineering polymers reinforced with renewable fibres (RF) are an attractive class of materials, due to their excellent mechanical performance and low environmental impact. However, the successful preparation of such composites has proven to be challenging due to the low thermal stability of RF. The aim of the present study was to investigate how different RF behaves under increased processing temperatures and correlate the thermal properties of the fibres to the mechanical properties of composites. For this purpose, hemp, flax and Lyocell fibres were compounded into polypropylene (PP) using a co-rotating twin screw extruder and test specimens were injection moulded at temperatures ranging from 180 °C to 260 °C, with 20 K steps. The decomposition behaviour of fibres was characterised using non-isothermal and isothermal simultaneous thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). The prepared composites were investigated using optical microscopy (OM), colorimetry, tensile test, Charpy impact test, dynamic mechanical analysis (DMA) and melt flow rate (MFR). Composites exhibited a decrease in mechanical performance at processing temperatures above 200 °C, with a steep decrease observed at 240 °C. Lyocell fibres exhibited the best reinforcement effect, especially at elevated processing temperatures, followed by flax and hemp fibres. It was found that the retention of the fibre reinforcement effect at elevated temperatures can be well predicted using isothermal TGA measurements.

scholarly journals On the Use of Paper Sludge as Filler in Biocomposites for Injection Moulding

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2688
Author(s):  
Vito Gigante ◽  
Patrizia Cinelli ◽  
Marco Sandroni ◽  
Roberto D’ambrosio ◽  
Andrea Lazzeri ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Mechanical Performance ◽  
Impact Resistance ◽  
Mechanical Tests ◽  
Lepidium Sativum ◽  
Poly Lactic Acid ◽  
Paper Sludge ◽  
Scanning Calorimetry ◽  
Twin Screw ◽  
Acetyl Tributyl Citrate

The potential use of paper sludge (PS) as filler in the production of bio-composites based on poly lactic acid (PLA) and polybutylene adipate terephthalate (PBAT) was investigated. PS/PLA/PBAT composites, with addition of acetyl tributyl citrate (ATBC) as biobased plasticizer, were produced with PS loadings up to 30 wt.% by twin-screw extrusion followed by injection moulding. The composites were characterized by rheological measurements, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mechanical tests (tensile and impact resistance) to study the effect of PS on the processability, thermal stability, crystallinity and mechanical performance of polymeric matrix. The optimized composites at higher PS content were successfully processed to produce pots for horticulture and, in view of this application, preliminary phytotoxicity tests were conducted using the germination test on Lepidium sativum L. seeds. Results revealed that developed composites up to 30 wt.% PS had good processability by extrusion and injection moulding showing that PS is a potential substitute of calcium carbonate as filler in the production of bio-composites, and the absence of phytotoxic effects showed the possibility of their use in the production of pots/items for applications in floriculture and/or horticulture.

Effect of Sn Component Surface Finish on 92.5Pb-5Sn-2.5Ag

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000364-000371
Author(s):  
Harry Schoeller ◽  
Martin Anselm ◽  
Imran Khan ◽  
Eric Cotts
Keyword(s):  
High Temperature ◽  
Mechanical Behavior ◽  
Surface Finish ◽  
Solder Joints ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Scanning Calorimetry ◽  
Microstructure Evaluation ◽  
Final Composition

This work investigates the effect of Sn component surface finish on the melting temperature, microstructure, and mechanical behavior of 92.5Pb-5Sn-2.5Ag. 92.5Pb-5Sn-2.5Ag was doped with up to 7% Sn to simulate the final composition of a joint after reflow with a component having Sn surface finish. Differential Scanning Calorimetry (DSC) was used to measure the change in matrix liquidus temperature with increasing Sn concentration. Microstructure evaluation and mechanical tests were carried out on 20 mil solder spheres reflowed on high temperature polyimide test coupons. Solder joints of each composition were cross-sectioned to examine the microstructure. The area fraction of β-Sn and Ag3Sn was quantified for each composition using image analysis software. Shear and isothermal fatigue tests of individual solder joints with varying Sn concentrations were conducted at room temperature. Joints were also sheared at 200°C after aging for 1024hrs at 200°C to simulate a downhole environment. The failed interfaces were examined to determine the mode of failure. Beyond providing guidance for surface finish selection, this work examines the microstructure and mechanical behavior of 92.5Pb-5Sn-2.5Ag as a function of Sn concentration and temperature. An understanding of the microstructure-mechanical performance relationship will aid in the development of new alloys for high temperature applications.

scholarly journals Effects of Interphase and Fibre Content on the Mechanical Behavior of Weft-Knitted Glass Fibre Reinforced Polypropylene

1997 ◽  
Vol 6 (2) ◽  
pp. 096369359700600 ◽  
Author(s):  
J. Karger-Kocsis ◽  
E. Moos ◽  
T. Czigány
Keyword(s):  
Mechanical Performance ◽  
Mechanical Tests ◽  
Fibre Content ◽  
Matrix Adhesion ◽  
Loading Mode ◽  
Static Tensile ◽  
Glass Fibre Reinforced ◽  
Flexural Tests ◽  
Commingled Yarns ◽  
Fibre Matrix

The mechanical performance of weft knitted glass fiber (GF) fabric-reinforced polypropylene (PP) composite sheets produced by hot pressing of stacked knit layers was investigated. The knits were built-up of commingled yarns showing extremely different fibre/matrix adhesion. The GF content of the commingled yarns was 50 (≍ 26 vol.%) and 70 wt.% (≍45 vol.%), respectively. The effects of fibre/matrix adhesion and fibre content were characterized by dynamic-mechanical thermoanalysis (DMTA), static tensile and flexural tests in both course (C) and wale (W) direction of the knit. In addition, the sheets were subjected to instrumented falling weight perforation impact (IFWI). It was found that the knit structure-related stiffness anisotropy depended on the loading mode of the composites. The detrimental effect of the poor adhesion between GF and PP was well reflected in all mechanical tests conducted.

scholarly journals Physico-mechanical and morphological studies of jute/glass reinforced epoxy composites and its hybrids

2021 ◽  
Author(s):  
Partha Pratim Das ◽  
◽  
Rohit Sahu ◽  
Vijay Chaudhary ◽  
Krovvidi Srinivas ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Hybrid Composites ◽  
Research Work ◽  
Experimental Studies ◽  
Mechanical Tests ◽  
Epoxy Composites ◽  
Morphological Studies ◽  
Glass Fibre Reinforced ◽  
Closed Mold ◽  
Composite Samples

Present research work emphasis on the fabrication and evaluation of the physico-mechanical performance of jute/glass fibre reinforced epoxy composites and their hybrids. Composite samples were fabricated by closed mold hand lay-up technique. Fibre/matrix interfacial adhesion of fractured specimens after mechanical tests was investigated using SEM (scanning electron microscope). Among J/Epoxy, G/Epoxy, J/G/Epoxy, J/G/Epoxy composites show the maximum Shore-D hardness value of 99 as compared to jute/epoxy and glass/epoxy of Shore-D hardness value of 96 and Hardness value of 98 Shore-D, respectively. Experimental studies have shown that there are superior Physico-mechanical properties of hybrid composites (jute/glass/epoxy).

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

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