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NUMERICAL SIMULATION OF THE STRENGTH OF WOODEN STRUCTURES:
APPLICATION TO HISTORIC PIANOFORTE
Michael Kaliske 1 *, Eckart Resch 1 , Jörg Schmidt 2
1 Institute for Structural Analysis, Technische Universität Dresden, Germany
2 Institute of Structural Mechanics, University of Leipzig, Germany
Abstract
Goal of the project to be presented is to introduce computer oriented simulation techniques and methods into
structural investigations and restoration tasks of historic pianofortes. In order to achieve a realistic description of
wooden structures at ultimate loadings, modelling of ductile behaviour under compression and brittle behaviour
at tension or shear loading is required. The underlying nonlinear framework for the simulation of the local and
global behaviour is based on the finite element method. The material formulations, which represent the state of
the art in modelling of wooden structures, will be adapted to the requirements of historic pianofortes.
1. Motivation
Historic instruments are part of our cultural heritage. The importance of old instruments is not only
restricted to aesthetical aspects, in fact, these instruments provide an opportunity to experience,
understand and interpret old music. Starting in the 1960s, a historically oriented movement has been
developing that tries to perform old music composed in the period from 1550 to 1850 on historic
instruments. Therefore, many musical instruments museums would like to investigate, conserve and
restore old instruments, bring them into a state so that they can be played. However, the steps
necessary for restoration may only be taken when the original substance can be preserved. Historic
pianofortes are endangered, particularly because of the lack of knowledge in the fields of structural
mechanics and construction. The project described below pays attention to this need of research.
2. Project
The goal of the project “Static structural analysis of historic pianofortes”, which is supported by the
Federal Foundation of Culture in Germany, is the restoration of the pianoforte constructed by Franz
Jakob Späth and Christoph Friedrich Schmahl (Inv. MS-30, Fig. 1) shown at the Händel-Haus-Halle.
The important aspects of restoration can be pointed out by looking at two other instruments of the
museum, the pianofortes built by Johann Schmidt in 1786 (MS-28) and Conrad Graf in 1835 (MS-44).
Both instruments are playable for the time being and will act as reference objects.
These two pianofortes are characterised by substantial distortions, cracks in components and
connections caused by stringing (see Figs. 2 and 3). Therefore, an emphasis of the project is the basic
understanding and analysis of these damages by investigating the statical and structural behaviour of
the instruments. The investigations will be carried out by using computer-aided simulations. The
obtained results will serve as a basis for developing restoration measures for the pianoforte.
Simultaneously, a research study to answer the following questions is being developed:
• assessment of the basic static construction with respect to stability in initial state,
• determination and assessment of the damage potential and sensitivity of certain construction
details,
• consequences of existing damages for the behaviour of the construction and
• long-term behaviour of the construction with respect to climate fluctuations.
* E-mail: michael.kaliske@tu-dresden.de
Joseph Gril (edited by), Wood Science for Conservation of Cultural Heritage –Braga 2008: Proceedings of the International
Conference held by COST Action IE0601 (Braga - Portugal, 5-7 November 2008, ISBN 978-88-6453-157-1 (print)
ISBN 978-88-6453-165-6 (online) © 2010 Firenze University Press