Understanding the role of friction and adhesion in the display of tapestries on slanted supports

Lennard, F. , Costantini, R. and Harrison, P. (2021) Understanding the role of friction and adhesion in the display of tapestries on slanted supports. Studies in Conservation, 66(1), pp. 32-43. (doi: 10.1080/00393630.2020.1761184)

Abstract

This paper reports on an investigation into slanted support, an increasingly common method of displaying tapestries in mainland Europe. Two factors contribute to the efficacy of slanted supports for tapestry: the angle of display and the degree of friction between the tapestry and the support. Initial analysis demonstrated that a small degree of slope, of 5°, has only marginal impact on reducing the load experienced by the tapestry. Experiments were carried out to compare the friction between small tapestry fragments and a range of fabrics commonly used to cover slanted supports. Lined and unlined tapestry fragments were placed on a fabric-covered board and tilted from horizontal to vertical. In most cases it was found that the board could be tilted beyond vertical before the tapestry began to slip; this meant it was not possible to calculate a coefficient of friction. It was clear that the simple Coulomb model of friction does not apply in this situation and that adhesive forces are even more significant than friction. Loading the tapestry samples demonstrated that the coefficient is dependent on load, confirming this observation. The paper also reports on the use of digital image correlation (DIC) to calculate strain data. A tapestry fragment was suspended on a vertical board half covered in cotton molton fabric. The strain values were very low on the half of the tapestry against the molton; they were higher on the half against the uncovered board. It was also apparent that the tapestry with board-covering fabric was less subject to expansion and contraction caused by fluctuating relative humidity. The research concluded that the friction/adhesion forces are so effective that a tapestry is well supported on a vertical fabric-covered board; there is no additional benefit in providing a small degree of slant.

• Item Type: Articles
• Additional Information: This work was supported by the Leverhulme Trust under Grant number RPG-2015-179.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lennard, Professor Frances and Harrison, Dr Philip and Costantini, Rosa
• Authors: Lennard, F., Costantini, R., and Harrison, P.
• College/School: College of Arts & Humanities > School of Culture and Creative Arts > History of Art; College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Studies in Conservation
• Publisher: Taylor and Francis
• ISSN: 0039-3630
• ISSN (Online): 2047-0584
• Published Online: 19 May 2020
• Copyright Holders: Copyright © The International Institute for Conservation of Historic and Artistic Works 2020
• First Published: First published in Studies in Conservation 66(1):32-43
• Publisher Policy: Reproduced in accordance with the publisher copyright policy