The Study Of Micro-Damage Evolution In Paper Material Based On Acoustic Emission

Due to effects of external conditions (such as external force by human activities), the paper materials experience random damage states unavoidably, which origins from the micro-damage evolution inhabited in paper structure. Many existing challenges have to be envisaged for studying the problem:multi-physics and multi-scale coupling and its current situations. To overcome these deficiencies, this article proposes an experimental and data-enabled methodology to study the micro-damage evolution based on acoustic emission (AE) data. Then AE data extracted from damage evolution were described and analyzed statistically in a multivariate method considering effects of multi-scale and multi-physics coupling, which are essential steps to develop accurate and further interpretation and understanding of this material failure nature.First, this paper describes the significance and procedure of studying deformation and fracture of the materials, especially for paper material. The randomness of damage events, their interaction, and the mutual effects of damage events and material inherent structure hold the key to making accurate characterization and evaluation of damage evolution in paper material. Here, a method of digital analytics of material damage was proposed. There are limited means capable of accomplishing the objectives among which AE is the most plausible for the characteristics of AE signatures, which is equivalent to quantify the damage events during fracture process of paper material. Then AE data featuring volume, variety, velocity, and variability was integrated as a measurable multivariate DA which included scale vectors and observation vectors.Secondly, the clay coated kraft back (CCKB), one typical grade of recycled paper for packaging material, was chosen as the case study. Data acquisition was accomplished by laboratory experiments of both tensile and tearing test on CCKB paper specimens and AE real-time monitoring. Moreover, optical damage recognition of damage surface morphology using scanning electron microscope offer us lots of valuable information of experimental evidence.Thirdly, information entropy was applied to assess damage states in the damage evolution under the framework of multivariate analytics. Ultimately, trajectory of damage states, obtained when correlated with varying time series, is adequate enough to provide a realistic description of whole micro-damage evolution process. And other multivariate analysis such as exploratory data analysis (Andrews plots), Spearman rank correlation analysis, and principle component analysis, were employed to study the coupling and interaction of damage events.This investigation presents a new attempt to explore problems of the micro-damage evolution in paper material and its mechanical characteristics based on data-enabled method. Presently, the measurement, evaluation and correlations of micro-damage evolution have been studied. Although data-enabled digital analytics of material damage is in its infancy, its potentiality in the wide field is much needed to advance our understanding of damage physics in both research and application.