Application of fracture mechanics for energetic effects predictions while wood sawing

Kazimierz A Orlowski,Tomasz Ochrymiuk,Anthony Atkins,Daniel Chuchala

doi:10.1007/s00226-013-0551-x

Kazimierz A Orlowski, Tomasz Ochrymiuk + Show 2 more

Open Access

https://doi.org/10.1007/s00226-013-0551-x

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Abstract

In the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, cutting forces (or power—more interesting from energetic point of view) could be considered from a point of view of modern fracture mechanics. Cutting forces may be employed to determine not only toughness but also shear yield strength, which are then applied in the models. Furthermore, forecasting of the shear plane angle for the cutting models, which include fracture toughness in addition to plasticity and friction, broadens possibilities of energetic effects modelling of the sawing process even for small values of the uncut chip. Mentioned models are useful for estimation of energetic effects of sawing of every kinematics. However, for band saws and circular sawing machines, the chip acceleration power variation as a function of mass flow and tool velocity ought to be included in analysis of sawing at larger cutting speeds.

Highlights

Theoretical and experimental determination of values of forces acting in the cutting process belongs to the basic and simultaneously the most developed field of mechanics of this process
In the classical approach, energetic effects of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors
Energetic effects of wood sawing process are generally calculated on the basis of the specific cutting resistance kc (Fischer 2004; Scholz et al 2009; Orlowski 2007), which in the case of wood cutting is the function of the following factors: wood species, cutting direction angle, moisture content, wood temperature, tooth geometry, tooth dullness, chip thickness and some others which are less important (Agapov 1983; Orlicz 1988)

Summary

Introduction

Theoretical and experimental determination of values of forces acting in the cutting process belongs to the basic and simultaneously the most developed field of mechanics of this process. Energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance kc (cutting force per unit area of cut) (Fischer 2004; Scholz et al 2009; Orlowski 2007), which in the case of wood cutting is the function of the following factors: wood species, cutting direction angle (cutting edge position in relation to wood grains), moisture content, wood temperature, tooth geometry, tooth dullness, chip thickness and some others which are less important (Agapov 1983; Orlicz 1988). For least force Fc, the shear angle Uc satisfies (Atkins 2003):

À À sin bÁl sin Uc cos bl À cf Á cosðUc À cfÞ

Results and discussion

Conclusion