Chen, Jian (2016)
Investigation on the Mechanical Behavior of Paper and Paper Stacks in the out-of-plane Direction.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
The purpose of the present study is to deeply investigate the mechanical behavior of paper materials in the out-of-plane direction, especially, the compressive behavior of a single sheet or multiple sheets. In this dissertation, the mechanical behavior of paper and paper stacks was detailed discussed from three different research perspectives. The surface roughness plays a very important role in the compressive behavior of paper materials. The first goal of the present study is to investigate the effect of the surface topography in calculating the stress-strain curve of paper. The difference between the actual and the nominal contact area was compared and a new experimental method by using carbon papers was proposed to measure the actual contact areas. With the aid of the image processing technology, the actual stress-strain curve of paper was calculated and compared with the nominal stress-strain curve. As indicated, there is an obvious difference between the actual and nominal stress-strain curves. A second goal of this study is to establish the mathematical model for describing the force-deformation behavior of multiple sheets. Two different methods with and without considering the paper structures were selected for building the paper models. With considering the structure, the paper can be regarded as an elastic material, the body of which can be divided into two rough surfaces and one internal structure. On the basis of Hooke’s law or Paetow’s method, the relationship between the total deformation and surface deformation can be calculated by using the Newton-Raphson method. Then, the force-deformation relation of a single sheet was derived according to the relationship between the surface and total deformation, the model of a single sheet was extended to calculate the force-deformation curves of multiple sheets. Without considering the structure, the loading and unloading stress-strain curve of paper were expressed by using a sextic polynomial equation and a modified exponential equation, respectively. Based on the hypothesis that when the force is the same, the deformations of the paper stacks are directly proportional to the sheet numbers, the force-deformation relation of multiple sheets was derived. By comparing with the experimental results, it shows that the maximum number of sheets which can be calculated by both of the proposed models is about 140 sheets, especially, when the numbers are between 20 and 140. In addition, without considering the effect of the surface roughness, the stress-strain curve of paper is a typical J-shaped curve. So, in this dissertation, a much easier way to simulate the paper material by using a gasket model was proposed. The material property was defined based on the experimental stress-deformation data under 100 N, then, some simulations under 20 N, 40 N, 60 N and 80 N were implemented based on the model established above. The findings indicated that, this method can be used with high confidence for the simulation of paper under different forces.
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2016 | ||||
Autor(en): | Chen, Jian | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Investigation on the Mechanical Behavior of Paper and Paper Stacks in the out-of-plane Direction | ||||
Sprache: | Englisch | ||||
Referenten: | Dörsam, Prof. Edgar ; Schabel, Prof. Samuel | ||||
Publikationsjahr: | 14 November 2016 | ||||
Ort: | Darmstadt | ||||
Datum der mündlichen Prüfung: | 1 November 2016 | ||||
URL / URN: | http://tuprints.ulb.tu-darmstadt.de/5770 | ||||
Kurzbeschreibung (Abstract): | The purpose of the present study is to deeply investigate the mechanical behavior of paper materials in the out-of-plane direction, especially, the compressive behavior of a single sheet or multiple sheets. In this dissertation, the mechanical behavior of paper and paper stacks was detailed discussed from three different research perspectives. The surface roughness plays a very important role in the compressive behavior of paper materials. The first goal of the present study is to investigate the effect of the surface topography in calculating the stress-strain curve of paper. The difference between the actual and the nominal contact area was compared and a new experimental method by using carbon papers was proposed to measure the actual contact areas. With the aid of the image processing technology, the actual stress-strain curve of paper was calculated and compared with the nominal stress-strain curve. As indicated, there is an obvious difference between the actual and nominal stress-strain curves. A second goal of this study is to establish the mathematical model for describing the force-deformation behavior of multiple sheets. Two different methods with and without considering the paper structures were selected for building the paper models. With considering the structure, the paper can be regarded as an elastic material, the body of which can be divided into two rough surfaces and one internal structure. On the basis of Hooke’s law or Paetow’s method, the relationship between the total deformation and surface deformation can be calculated by using the Newton-Raphson method. Then, the force-deformation relation of a single sheet was derived according to the relationship between the surface and total deformation, the model of a single sheet was extended to calculate the force-deformation curves of multiple sheets. Without considering the structure, the loading and unloading stress-strain curve of paper were expressed by using a sextic polynomial equation and a modified exponential equation, respectively. Based on the hypothesis that when the force is the same, the deformations of the paper stacks are directly proportional to the sheet numbers, the force-deformation relation of multiple sheets was derived. By comparing with the experimental results, it shows that the maximum number of sheets which can be calculated by both of the proposed models is about 140 sheets, especially, when the numbers are between 20 and 140. In addition, without considering the effect of the surface roughness, the stress-strain curve of paper is a typical J-shaped curve. So, in this dissertation, a much easier way to simulate the paper material by using a gasket model was proposed. The material property was defined based on the experimental stress-deformation data under 100 N, then, some simulations under 20 N, 40 N, 60 N and 80 N were implemented based on the model established above. The findings indicated that, this method can be used with high confidence for the simulation of paper under different forces. |
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URN: | urn:nbn:de:tuda-tuprints-57709 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 600 Technik, Medizin, angewandte Wissenschaften > 600 Technik 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
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Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Institut für Druckmaschinen und Druckverfahren (IDD) |
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Hinterlegungsdatum: | 20 Nov 2016 20:55 | ||||
Letzte Änderung: | 20 Nov 2016 20:55 | ||||
PPN: | |||||
Referenten: | Dörsam, Prof. Edgar ; Schabel, Prof. Samuel | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 1 November 2016 | ||||
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