A New Technique for Determining the Shape of a Paper Sample in In-Plane Compression Test Using Image Sequence Analysis

Abstract

The article presents a new technique for analyzing phenomena occurring during the measurement of the strength properties of paper in the conditions of compression of the tested samples with forces acting in the paper plane. The technique is based on collecting data on the current distance of the clamps holding the tested sample and the force exerted on the sample using a universal testing machine and on the simultaneous recording of image sequence of the sample during the measurement. Next, the resulting images are subjected to processing and analysis, the purpose of which is to extract information about the shape of the sample edge in all phases of the measurement. Its advantage is the ability to determine the deflection arrow of the sample and describe its shape using the selected function given by the analytical parametric formula. It will be helpful in further research on the development of an analytical model describing the phenomena occurring during paper compression, and a method to determine the mechanism of paper destruction and the corresponding maximum force that destroys a paper sample.

New Models for Calculating the Maximum Compressive Force of Paper in Its Plane

“…During the tests, a series of images of the edges of the compressed paper was made, which allowed us to observe changes in its shape and experimentally determine the size of the deflection arrow of the sample. Detailed results are presented in [ 23 ].…”

“…The shape of a paper sample subjected to compressive forces is shown in Figure 1 a. More figures showing the different stages of paper compression can be found in [ 23 ]. According to Królak [ 38 ] and Murray, Khoo [ 39 ], mechanism 1 of the destruction of the paper web with a thickness g , length l and width b , freely supported on both loaded edges has the form presented in Figure 1 b.…”

“…Taking into account the results of research presented in [ 23 ], two cases of shortening the paper web of length l were considered: Case 2A: AB = BC = CE = EF = l /4 ( Figure 4 ): Case 2B: AB = EF = 3 l /8; BC = CE = l /8 ( Figure 4 ): …”

“…The currently intensively developed measurement techniques based on the simultaneous analysis of universal testing machine data and the sequences of images of the tested samples are helpful here (Pełczyński et al [ 22 ]). The authors also developed a technique based on the fusion of data from these two sources (Pełczyński et al [ 23 ]), which facilitated further research work. The subject of the presented research was to develop an accurate, and at the same time easy to apply, practical model describing the load capacity of the paper web depending on its fastening length.…”

“…The testing machine used allowed for web lengths up to 5.0 mm. In [ 23 ], the authors presented a methodology for testing compressed paper webs, and this article is a continuation of that work, presenting a method for determining the load-bearing capacity of paper webs. The article also provides a formula for calculating the deflection mechanism without providing specific details about the mechanism itself and determining the load-bearing capacity.…”