A deep retaining structure in till and sand. Part II: Performance and analysis

1983 ◽  
Vol 20 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Z. Eisenstein ◽  
L. V. Medeiros

The problem of magnitude and distribution of lateral pressure acting on a deep retaining structure supporting an excavation in till and sand is studied by an approach integrating field measurements from a case history with a finite element analysis. Also studied are ground movements associated with the excavation. The finite element analysis is based on stress path dependent testing of the soils involved.The case history is the behaviour of a deep supported wall of the underground Churchill Square Station of the recently built line of the Light Rail Transit System in Edmonton. A tangent pile wall, 17 m deep, has been placed through glacial till to underlying sands. The site has been instrumented to record displacements of the wall and of the surrounding ground as well as the loads carried by the lateral supports.A finite element analysis employing several stress–strain models was used to simulate the excavation and its sequence, the placement of lateral support, and the differential stiffness of the structural components and of the surrounding soil. Special attention has been given to the effect of different stress–strain models of soils, with a particular focus on the influence of stress paths typical for the studied structure.Agreement between the field and analytical results for displacements is accepted as a criterion of validity of the analytical results of stresses, where direct in situ stress measurements are difficult to obtain and interpret. Of special importance is the calculated lateral pressure against the wall and its relation to the stiffness of the wall and to the magnitude of associated ground movements. The calculated lateral pressure has been found to differ significantly from the semiempirical design pressure diagrams used in practice.The soil stress–strain model found to describe the field behaviour most closely has been derived from test results obtained using a plane strain apparatus. Keywords: deep supported excavation, displacement, lateral pressure, field measurement, finite element analysis.

2015 ◽  
Vol 76 ◽  
pp. 522-527
Author(s):  
M. Shamil Jaffarullah ◽  
Nur’Amirah Busu ◽  
Cheng Yee Low ◽  
J.B. Saedon ◽  
Armansyah ◽  
...  

2019 ◽  
Vol 823 ◽  
pp. 141-144
Author(s):  
Tung Sheng Yang ◽  
Yong Nan Chen

The feasibility of forging of AL-1050 alloy of cylindrical heatsink under warm conditions is demonstrated in the present work. The stress-strain curves and friction factor play an important role in the cylindrical heatsink forging. The purpose of forging lubrication is to reduce friction between blank and die, and to decrease resistance of metal flow to die. The stress-strain curves at different temperatures are obtained by compressing tests. The friction factor between 1050 aluminum alloy and die material are determined at different temperatures by ring compression tests with graphite lubricants. The compressing and ring compressing tests are carried out by using the computerized screw universal testing machine. The finite element method is used to investigate the forming characters of the forging process. To verify the prediction of FEM simulation in the cylindrical heatsink forging process, the experimental parameters such as stress-strain curves and fiction factor, are as the input data during analysis. Maximum forging load and effective stress distribution are determined of the heatsink forging, using the finite element analysis. Finally, the cylindrical heatsink parts are formed by the forging machine under the conditions using finite element analysis.


2018 ◽  
Vol 28 (6) ◽  
pp. 1200-1215 ◽  
Author(s):  
Rahul BHANDARI ◽  
Prosanta BISWAS ◽  
Manas Kumar MONDAL ◽  
Durbadal MANDAL

Author(s):  
MK Samal ◽  
KS Balakrishnan ◽  
J Parashar ◽  
GP Tiwari ◽  
S Anantharaman

Determination of transverse mechanical properties from the ring type of specimens directly machined from the nuclear reactor pressure tubes is not straightforward. It is due to the presence of combined membrane as well as bending stresses arising in the loaded condition because of the curvature of the specimen. These tubes are manufactured through a complicated process of pilgering and heat treatment and hence, the transverse properties need to be determined in the as-manufactured condition. It may not also be possible to machine small miniaturized specimen in the circumferential direction especially in the irradiated condition. In this work, we have performed ring-tensile tests on the un-irradiated ring tensile specimen using two split semi-cylindrical mandrels as the loading device. A three-dimensional finite element analysis was performed in order to determine the material true stress–strain curve by comparing experimental load–displacement data with those predicted by finite element analysis. In order to validate the methodology, miniaturized tensile specimens were machined from these tubes and tested. It was observed that the stress–strain data as obtained from ring tensile specimen could describe the load–displacement curve of the miniaturized flat tensile specimen very well. However, it was noted that the engineering stress–strain as directly obtained from the experimental load–displacement curves of the ring tensile tests were very different from that of the miniaturized specimen. This important aspect has been resolved in this work through the use of an innovative type of 3-piece loading mandrel.


2016 ◽  
Vol 685 ◽  
pp. 186-190 ◽  
Author(s):  
Е.V. Eskina ◽  
E.G. Gromova

The paper describes the method of manufacture of profiles in cramped bending conditions using polyurethaneThe scope of studies included stress-strain state of elastic die and parent sheet, as well as the influence of the basic process parameters on characteristics of the produced items using ANSYS software.


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