Damage Characterization of Bio and Green Polyethylene–Birch Composites under Creep and Cyclic Testing with Multivariable Acoustic Emissions

Abstract

Despite the knowledge gained in recent years regarding the use of acoustic emissions (AEs) in ecologically friendly, natural fiber-reinforced composites (including certain composites with bio-sourced matrices), there is still a knowledge gap in the understanding of the difference in damage behavior between green and biocomposites. Thus, this article investigates the behavior of two comparable green and biocomposites with tests that better reflect real-life applications, i.e., load-unloading and creep testing, to determine the evolution of the damage process. Comparing the mechanical results with the AE, it can be concluded that the addition of a coupling agent (CA) markedly reduced the ratio of AE damage to mechanical damage. CA had an extremely beneficial effect on green composites because the Kaiser effect was dominant during cyclic testing. During the creep tests, the use of a CA also avoided the transition to new damaging phases in both composites. The long-term applications of PE green material must be chosen carefully because bio and green composites with similar properties exhibited different damage processes in tests such as cycling and creep that could not be previously understood using only monotonic testing.

Mechanical Properties, Wettability and Thermal Degradation of HDPE/Birch Fiber Composite

“…The tensile and impact properties of linear low-density polyethylene (LLDPE) reinforced with up to 30% aspen fiber coupled with a silane [ 27 ] and up to 40% coupled with a titanate [ 28 ] have been studied. Birch-fiber-reinforced polyethylene composite has been studied in terms of creeping [ 29 ], tensile properties [ 13 , 30 ], compatibilized interfacial adhesion and effects of recycling on mechanical properties [ 31 , 32 , 33 ]. Birch is a common hardwood tree that grow in cool areas with abundant precipitation, such as the province of Quebec, Canada [ 29 , 34 ].…”

“…Birch-fiber-reinforced polyethylene composite has been studied in terms of creeping [ 29 ], tensile properties [ 13 , 30 ], compatibilized interfacial adhesion and effects of recycling on mechanical properties [ 31 , 32 , 33 ]. Birch is a common hardwood tree that grow in cool areas with abundant precipitation, such as the province of Quebec, Canada [ 29 , 34 ].…”

Development of sustainable biodegradable lignocellulosic hemp fiber/polycaprolactone biocomposites for light weight applications

“…Their review paper further concluded that banana possesses an excellent mechanical properties such as tensile strength and modulus as well as flexural properties, impact energy, to mention but a few [26] Additionally, there are several reported works on the development and properties of natural fiber reinforced thermoplastic composites and biodegradable biocomposites for various engineering applications. These properties include, but are not limited to, thermal degradation kinetics [27], mechanical (elastic modulus, tensile strength and modulus), thermo-physical (degradability) and structural [28], among others as well as cyclic and creep [29] and mechanical (3-pont flexural and monotonic tensile) [30]. For examples, the experimental work carried out by Talla et al [31] highlighted the effects of hemp fiber reinforcement on the mechanical and structural properties of polyethylene terephthalate (PET)-hemp fiber composite samples.…”

Fatigue of short‐natural‐fiber‐reinforced high‐density polyethylene: Stochastic modeling of single‐gear‐tooth bending

“…The first step in the development of a new material is the testing of its basic mechanical properties. The composite proposed in this study has tension, 7 bending, 7 cyclic creep, 8 and fatigue bending 3,9 properties comparable to those of technical plastics. To get industries to use new materials, research is often focused on developing off‐the‐shelf components such as gears.…”

“…Another method used to quantify damage for component life prediction purposes is acoustic emission 27,37 . Several types of measurement can be used with acoustic emission, such as energy, duration, peak amplitude, count, and frequency 8 . Energy is advantageous when noise is a problem, since acoustic noise has low energy and will have less effect on the total damage estimation.…”