By George A. Petrides
Этот иллюстрированный определитель включает детальные описания 387 видов, объединенных в 6 групп по внешнему сходству. forty seven цветных вкладок и текстовые описания характеризуют особенности видов, необходимые для идентификации. Цветные фотографии и 295 карт распространения дополняют видовые описания.
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Extra info for A Field Guide to Western Trees: Western United States and Canada
1, trees will the earlier~ compressive (see Chap. or value. The c a n t i l e v e r frac- by the external bending moment, strength discussed whose cantilevers caused material wood is strength Table is which the extremely an- about 2 and Fig. therefore of an 5). generally half the In bending, fail on the com- p r e s s i o n side first. The fracture strength of external the altering the the d e n s i t y near the base are and (SCHNIEWIND Ii). load is to accordance angle 1962, optimize with shorter Eq.
I i ! tit Itl t t~t ! tit C ) -_= Fig. 15. C r a c k s and t o u g h n e s s of strong materials, a Stress d i s t r i b u tion near the c r a c k tip. b The t o u g h n e s s of strong m a t e r i a l s can be i n c r e a s e d by r e d u c i n g the stress c o n c e n t r a t i o n near the crack tip; this can be done in v a r i o u s ways: I by using d u c t i l e material; 2 by using i s o l a t e d s t r e n g t h e n i n g elements; 3 by r o u n d i n g off the c r a c k tip. c C O O K - G O R D O N m e c h a n i s m of c r a c k stopping: w e a k i n t e r f a c e s may act es c r a c k - s t o p p e r s since they, too, reduce the stress c o n c e n t r a tion (further e x p l a n a t i o n in the t e x t ) .
After J E R O N I M I D I S 1980) 46 the central Thus parts experience a compressive prestressing represents a simple duce the p e r i p h e r a l tor against lated compressive fracture that a due peripheral pression strength diameter by 9% and for selective occurrence able. of But all kinds In also it context widely used it that periphery and prestressing crack are show a is u s e d the o u t s i d e inner If a s t r u c t u r e material. 5 Ee 2 for the limit", to the linearly point failure".
A Field Guide to Western Trees: Western United States and Canada by George A. Petrides