Combined Stresses in Forests

2014 ◽  
pp. 223-244 ◽  
Author(s):  
Patrick Mitchell ◽  
Tim Wardlaw ◽  
Libby Pinkard
Keyword(s):  
2020 ◽  
Vol 80 (03) ◽  
Author(s):  
Renu Pandey ◽  
Surendra Kumar Meena ◽  
Gayacharan . ◽  
Madan Pal Singh

Experiments were conducted to study the genotypic variability for tolerance to combined stresses of low availability of phosphorus (P) and drought in 14 mungbean [Vigna radiata (L.) R. Wilczek] accessions. The accessions were evaluated under four conditions viz., control (sufficient P, irrigated), low P (without P, irrigated), drought (sufficient P, withholding irrigation) and combined stresses (low P, withholding irrigation). The relative stress tolerance was estimated for 22 agro-physiological traits. The principal component analysis (PCA) and relative stress indices (RSIs) of traits exhibited significant variation among the treatments and accessions. Based on RSIs, the PCA ranking analysis showed that the accessions IC 280489, PDM 139 and IC 76491 were highly ranked and tolerant to low P, drought and combined stresses. The relative increase in component traits such as photosynthetic parameters, relative water content, above-ground biomass, seed P content and number of pods plant–1 were higher while canopy temperature and water use efficiency were reduced in tolerant accessions. In contrast, IPM 2-3 was found to be relatively sensitive to all three treatments. Tolerant accessions may be either included in the breeding program or used directly as cultivar that can be grown under low P and drought.


1970 ◽  
Vol 53 (12) ◽  
pp. 649-654 ◽  
Author(s):  
L. J. BROUTMAN ◽  
S. M. KRISHNAKUMAR ◽  
P. K. MALLICK
Keyword(s):  

1936 ◽  
Vol 101 (1) ◽  
pp. 1179-1193
Author(s):  
J. J. Slade ◽  
T. McLean Jasper ◽  
I. K. Silverman ◽  
W. P. Roop ◽  
H. F. Moore ◽  
...  

1957 ◽  
Vol 122 (1) ◽  
pp. 1049-1059
Author(s):  
Boris Bresler ◽  
Karl S. Pister

1955 ◽  
Vol 22 (1) ◽  
pp. 77-85
Author(s):  
L. W. Hu ◽  
Joseph Marin

Abstract A loading function is a relation between combined stresses for which the beginning of plastic flow takes place. The loading function for a given material is different depending upon the initial plastic strains produced. That is, the initial stress or strain history influences the subsequent loading function. This paper gives the results of an experimental investigation to determine the validity of certain loading functions proposed for anisotropic materials. The study reported was conducted for an aluminum alloy 24S-T and the state of stress covered was biaxial tension. These stresses were produced in the usual way by subjecting thin-walled tubular specimens to axial tension and internal pressure. The test results showed that none of the existing loading functions is adequate for interpreting the plastic stress-strain relations obtained. Tests also were made to determine the change in the loading function with increase in plastic flow. It was found that the loading function did not remain symmetrical with respect to the original function, nor was the new loading function the same as the original except for a shift of origin. However, the test results support in a qualitative way the concept of the so-called “yield corner.”


Author(s):  
R.K. Sarkar ◽  
K. Chakraborty ◽  
K. Chattopadhyay ◽  
S. Ray ◽  
D. Panda ◽  
...  
Keyword(s):  

In certain problems of plastic flow, for example, a thick tube expanded by internal pressure, it is important to consider changes in the elastic strain of material which is flowing plastically in order to deduce the correct stress distribution and deformation. The usual plastic theory which neglects elastic strains in the plastic region may lead to considerable errors in certain cases. In this paper we review the theory of the deformation of a material under combined stresses which involves both elastic and plastic components of strain. The relationship between stress and strain is represented on a plane diagram, the reduced stress-strain diagram, which facilitates discrimination between the elastic and plastic components of strain and aids considerably the solution of certain problems. The diagram can also be used to express the relationships governing the dissipation of energy during plastic flow under combined stresses. The theory is applied to the deformation of a long thick tube under internal pressure with zero longitudinal extension. The solution is compared with that based on the usual theory which neglects elastic strains in the plastic region, revealing an error which reaches a maxi­mum of over 60% in the longitudinal stress distribution. The significance of the differences between the two solutions is discussed in detail.


Sign in / Sign up

Export Citation Format

Share Document