Method of estimating timber stiffness profiles
AssigneeCarter Holt Harvey Limited
InventorsMichael Kenneth Andrews, Christhoper Anthony Gerard Desmond
Life of this patent
Estimating the term…
Abstract
The invention relates to methods and apparatus for estimating stiffness or elasticity profiles across timber. This involves measuring a velocity of a plane compression wave propagating in the timber, determining density information relating to the timber and estimating an initial elasticity profile. A reiterative process is then conducted whereby a revised elasticity profile is determined using the density information and initial elasticity profile. The revised elasticity profile is then used to determine how the timber is utilised.
Claims35
A method of breaking down a stem, log, cant or slab which comprises or includes the steps of:
- determining an acoustic velocity value for the stem, log, cant or slab,
- predicting a stiffness profile across the stem, log, or cant as a function of the acoustic velocity and a density profile across the stem, log, cant or slab, and
- utilising the stiffness profile in cutting the stem, log, cant or slab.
A method of estimating elasticity or stiffness across a length of timber including:
- measuring the velocity of a compression wave in the timber,
- providing information as to density for the timber,
- calculating an initial profile of elasticity or stiffness across the timber using an elasticity model of the timber, and
- determining a revised elasticity or stiffness profile using the measured velocity, density information and initial elasticity profile.
A method of estimating elasticity or stiffness across a length of timber including:
- measuring the velocity of a compression wave in the timber,
- providing information as to density for the timber,
- calculating a profile of elasticity or stiffness across the timber using an elasticity model of the timber, and
- validating the elasticity or stiffness profile by calulating a velocity of a compression wave in the timber using the density information and elasticity or stiffness profile and comparing the calculated velocity with the measured velocity.
Apparatus for breaking down a tree stem, log, cant or slab of wood including:
- means arranged to determine an acoustic velocity value for the stem, log, cant or slab,
- means arranged to predict a stiffness profile across the stem, log, cant or slab as a function of the acoustic velocity and a density profile across the stem, log, cant or slab.
Apparatus for estimating elasticity or stiffness across a length of timber including:
- means for measuring the velocity of a compression wave in the timber,
- means for providing information as to density for the timber, and
- means arranged to calculate an initial profile of elasticity or stiffness across the timber using an elasticity model of the timber, and to determine a revised elasticity or stiffness profile using the measured velocity, density information and initial elasticity profile.
Apparatus for estimating elasticity or stiffness across a length of timber including:
- means for measuring the velocity of a compression wave in the timber,
- means for providing information as to density for the timber, and
- means arranged to calculate a profile of elasticity or stiffness across the timber using an elasticity model of the timber, and to validate the elasticity or stiffness profile by calulating a velocity of a compression wave in the timber using the density information and elasticity or stiffness profile and comparing the calculated velocity with the measured velocity.
A method of managing the breakdwon of a tree stem which comprises or includes the steps of:
- felling the tree stem,
- assessing the tree stem for breakdown into sawn timber,
- optionally cutting the tree stem into a log or logs,
- breaking tree stem or log(s) down into a cant and side parts,
- cutting the side parts to structural timber pieces,
- cutting the cant to a mixture of timber pieces cut to structural dimensions and to industrial dimensions, the cutting pattern of the cant having been determined with reliance upon the product of the average density or a density profile across the cant and a function of an average acoustic speed of the tree stem, cant or log.
Dependencies are inferred from the claim text.