Claus Mattheck, H. Kubler

Wood - The Internal Optimization of Trees

• Broschiertes Buch

Produktbeschreibung

Wood is a biological structure well-adapted to external loading. It carries axial loads in a tree by longitudinal fibres and radial loads by rays; circumferential compressive growth stresses prevent the tree from splitting along the rays. It is shown that axial and lateral strength is highest at places of maximum loading. Also, growth stresses are distributed in a load-controlled way. The vivid style used by the authors avoids complex formulas, preferring many impressive and simple to understand drawings. They show how a tree is internally optimized and how the partial or global breakdown of this interwoven axial and radial optimization can lead to the different failure modes.

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Mit mehr als 100 schönen wie amüsanten Zeichnungen und viel didaktischem Geschick zeigen die Autoren, daß die Innenarchitektur der Bäume optimal an die Belastung angepaßt ist. Die Holzqualität ist da am höchsten, wo dem Baum die meiste Gefahr droht, wo also in seinem Inneren die größten Spannungen wirken.

Produktdetails

• Springer Series in Wood Science
• Verlag: Springer / Springer Berlin Heidelberg / Springer, Berlin
• Artikelnr. des Verlages: 978-3-540-62019-8
• 1997.
• Seitenzahl: 144
• Erscheinungstermin: 30. Januar 1997
• Englisch
• Abmessung: 235mm x 155mm x 9mm
• Gewicht: 228g
• ISBN-13: 9783540620198
• ISBN-10: 3540620192
• Artikelnr.: 06145894

Inhaltsangabe

1 Introduction.- 2 Mechanical Fundamentals.- 2.1 External Loading and Internal Stresses.- 2.2 Thermal Expansion and Thermal Stresses.- 2.3 The Finite-Element Method (FEM).- 2.4 Notches and Notch Stresses - The Component Killers.- 2.5 Crack Propagation.- 2.6 The Main Mechanical Aspects.- 3 The Mechanical Self-Optimization of Trees - Five Theorems.- 3.1 The Five Theorems.- 4 The Principle of Minimum Lever Arms.- 4.1 Negative Gravitropism.- 4.2 The Flexibility Strategy.- 5 The Axiom of Uniform Stress.- 5.1 The Undisturbed Design.- 5.2 Repair Growth.- 5.3 Computer-Aided Optimization - CAO.- 6 Parallel Fiber and Force Flow Arrangement.- 6.1 The Principal Stress Trajectories are Shear-Free Lines.- 6.2 Computer-Aided Internal Optimization - CAIO.- 6.3 Spindle Shapes - Advantages and Problems.- 6.4 Fiber Deviations.- 6.4.1 Mechanically Controlled Spiral Grain.- 6.4.2 Genetically Programmed Spiral Grain.- 6.4.3 The Risks of Spiral Grain.- 7 Tree Rings and Force Flow.- 7.1 Longitudinal Tree Ring Arrangement.- 7.2 Tangential Tree Ring Arrangement.- 8 Growth Stresses.- 8.1 Qualitative Description.- 8.2 Longitudinal Stresses.- 8.3 Lateral Stresses.- 8.4 Selected Techniques for Measuring Growth Stresses.- 8.4.1 Visual Evaluation.- 8.4.2 Measurement of Growth Stresses with an Increment Borer.- 8.4.3 Growth Stress Measurement with Prismatic Samples.- 8.4.4 Growth Stress Measurement Between Two Pocket Holes.- 8.4.5 Single-Hole Growth Stress Measurement.- 8.4.6 Tangential Growth Stress Measurement on Radial Saw Cuts.- 9 Stress-Controlled Strength Distribution.- 9.1 The Wood-Concrete Analogy.- 9.2 Radial Transverse Strengths and Hazard Beams.- 9.3 Tangential Transverse Strengths in Leaning Trees.- 9.4 Strengths in the Residual Walls of Hollow Trees.- 10 Cracks.- 10.1 FrostCracks.- 10.2 Shear Cracks.- 10.3 Enclosed Bark.- 10.4 Hazard Beams.- 10.5 Ring Shakes.- 10.6 Grown Cracks on the Upper Sides of Branch Joints.- 10.7 T-Cracks.- 10.8 Drought Cracks.- 11 Final Remarks - Review and Outlook.- Reference.