Acoustic emission as a valuable technique used for monitoring polymer failures

2021 ◽  
Vol 66 (1) ◽  
pp. 34-44
Author(s):  
Jakub Skoczylas ◽  
Sylwester Samborski ◽  
Mariusz Kłonica
Keyword(s):  
Acoustic Emission ◽  
Epoxy Resin ◽  
Elastic Waves ◽  
Wavelet Transformation ◽  
Double Cantilever Beam ◽  
Thick Layer ◽  
Fast Fourier Transformation ◽  
Curing Agent ◽  
Fracture Tests ◽  
Aluminum Profiles

In the paper, acoustic emission (AE) system was presented as a method that can be used to monitor polymer material failures. Samples fabricated of two aluminum profiles bonded together with a thick layer of cured epoxy resin were subjected to fracture tests. Epidian 53 epoxy resin cured with Z1 curing agent as well as Epidian 5 epoxy resin cured with PAC curing agent were selected as adhesives. Acoustic emission parameters were acquired during Double Cantilever Beam (DCB) tests. The frequencies of elastic waves released during failure were then analyzed using both Fast Fourier Transformation (FFT) and Wavelet Transformation (WT) for the two materials.

Preparation and analysis of a flexible curing agent for epoxy resin

2009 ◽  
Vol 114 (5) ◽  
pp. 2706-2710 ◽  
Author(s):  
Y. Yang ◽  
Gong Chen ◽  
K. M. Liew
Keyword(s):  
Epoxy Resin ◽  
Curing Agent

scholarly journals Synthesis of antibacterial polyether biguanide curing agent and its cured antibacterial epoxy resin

2021 ◽  
Vol 24 (1) ◽  
pp. 63-72
Author(s):  
Rui Li ◽  
Guoxing Yang ◽  
Yudan Wang ◽  
Lijia Liu ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Curing Agent

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

Guided Wave Acoustic Emission from Fatigue Crack Growth in Aluminium Plate

2006 ◽  
Vol 13-14 ◽  
pp. 23-28 ◽  
Author(s):  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Paul D. Wilcox ◽  
M.R. Wisnom ◽  
Michael I. Friswell ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Elastic Waves ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Alloy Plate

Acoustic emission (AE) testing is an increasingly popular technique used for nondestructive evaluation (NDE). It has been used to detect and locate defects such as fatigue cracks in real structures. The monitoring of fatigue cracks in plate-like structures is critical for aerospace industries. Much research has been conducted to characterize and provide quantitative understanding of the source of emission on small specimens. It is difficult to extend these results to real structures as most of the experiments are restricted by the geometric effects from the specimens. The aim of this work is to provide a characterization of elastic waves emanating from fatigue cracks in plate-like structures. Fatigue crack growth is initiated in large 6082 T6 aluminium alloy plate specimens subjected to fatigue loading in the laboratory. A large specimen is utilized to eliminate multiple reflections from edges. The signals were recorded using both resonant and nonresonant transducers attached to the surface of the alloy specimens. The distances between the damage feature and sensors are located far enough apart in order to obtain good separation of guided-wave modes. Large numbers of AE signals are detected with active fatigue crack propagation during the experiment. Analysis of experimental results from multiple crack growth events are used to characterize the elastic waves. Experimental results are compared with finite element predictions to examine the mechanism of AE generation at the crack tip.

scholarly journals A Study on the Synthesis, Curing Behavior and Flame Retardance of a Novel Flame Retardant Curing Agent for Epoxy Resin

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 245
Author(s):  
Yong Sun ◽  
Yongli Peng ◽  
Yajiao Zhang
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Decomposition Temperature ◽  
Isothermal Kinetics ◽  
Flame Retardance ◽  
Curing Agent ◽  
Initial Decomposition Temperature ◽  
Limiting Oxygen Index ◽  
Epoxy Resin System ◽  
Dsc Method

In this work, a flame retardant curing agent (DOPO-MAC) composed of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO and methyl acrylamide (MAC) was synthesized successfully, and the structure of the compound was characterized by FT-IR and 1H-NMR. The non-isothermal kinetics of the epoxy resin/DOPO-MAC system with 1% phosphorus was studied by non-isothermal DSC method. The activation energy of the reaction (Ea), about 46 kJ/mol, was calculated by Kissinger and Ozawa method, indicating that the curing reaction was easy to carry out. The flame retardancy of the epoxy resin system was analyzed by vertical combustion test (UL94) and limiting oxygen index (LOI) test. The results showed that epoxy resin (EP) with 1% phosphorus successfully passed a UL-94 V-0 rating, and the LOI value increased along with the increasing of phosphorus content. It confirmed that DOPO-MAC possessed excellent flame retardance and higher curing reactivity. Moreover, the thermal stability of EP materials was also investigated by TGA. With the DOPO-MAC added, the residual mass of EP materials increased remarkably although the initial decomposition temperature decreased slightly.

Phosphorus- and silicon-containing amino curing agent for epoxy resin

2020 ◽  
Vol 29 (5) ◽  
pp. 433-443 ◽  
Author(s):  
Ajinkya Satdive ◽  
Siddhesh Mestry ◽  
Pavan Borse ◽  
Shashank Mhaske
Keyword(s):  
Epoxy Resin ◽  
Curing Agent

scholarly journals The application of a phosphorus nitrogen flame retardant curing agent in epoxy resin

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 545-554 ◽  
Author(s):  
Anxin Li ◽  
Pingli Mao ◽  
Bing Liang
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Adhesive Strength ◽  
Chemical Structure ◽  
Phosphorus Content ◽  
Raw Material ◽  
Curing Agent ◽  
Thermal Degradation Behavior ◽  
Overall Performance ◽  
The Impact

AbstractIn order to improve the compatibility of flame retardant and epoxy resin, a phosphorus nitrogen flame retardant curing agent poly(p-xylylenediamine spirocyclic pentaerythritol bisphosphonate) (PPXSPB) was synthesized. FTIR, 1HNMR, and mass spectroscopy were used to identify the chemical structure of PPXSPB. Epoxy resin (E-44) and PPXSPB as the raw material, a series of thermosetting systems were prepared. The effects of PPXSPB on flame retardancy, water resistance, thermal degradation behavior, mechanical properties and the adhesive strength of EP/PPXSPB thermosets were investigated. The results show that with the increase of phosphorus content, the oxygen index and carbon residue of the system both increased significantly, and the heat release rate gradually decreased, which is of great significance in delaying the occurrence of fire. When the phosphorus content is 3.24% in EP/PPXSPB thermosets, EP-2 can successfully pass the UL94 V-0 flammability rating, the LOI value of EP-2 can reach 31.4%, the impact strength and tensile strength was 6.58 kJ/m2 and 47.10 MPa respectively, and the adhesive strength was 13.79 MPa, the system presents a good overall performance.

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