Solution of a three-dimensional axisymmetrical problem of thermoplasticity in relation to thick turbine disks

1974 ◽  
Vol 6 (5) ◽  
pp. 530-536 ◽  
Author(s):  
V. V. Piskun ◽  
V. G. Savchenko ◽  
Yu. N. Shevchenko
Keyword(s):  
Three Dimensional ◽  
Axisymmetrical Problem ◽  
Turbine Disks

Probabilistic Fracture Mechanics for Mature Service Frame Rotors

2020 ◽  
Author(s):  
Philipp Engels ◽  
Christian Amann ◽  
Sebastian Schmitz ◽  
Kai Kadau
Keyword(s):  
Fracture Mechanics ◽  
Probabilistic Approach ◽  
Three Dimensional ◽  
Design Tools ◽  
Simulation Design ◽  
Probabilistic Fracture Mechanics ◽  
Service Business ◽  
Heterogeneous Nature ◽  
Turbine Disks ◽  
Turbine Design

Abstract Large gas turbine design and service business are challenged with increased demands towards flexible operations, increasing number of start-stop cycles and intermediate cycles. Probabilistic fracture mechanics (PFM) simulation design tools have matured and became robust and reliable. We present a probabilistic re-evaluation of Siemens E-class turbine disks by the combination of probabilistic two-dimensional axisymmetric part analysis of the disk and a novel probabilistic approach for the three-dimensional blade attachment. The first addresses the risk of inherent forging flaws, the latter combines the risk of surface crack initiation, growth and failure. Both models consider the heterogeneous nature of material properties, flaw geometries and detectability. These novel concepts developed at Siemens allow for an optimization of resource usage and safety, as well as the development of new service and inspection concepts for a variety of service frames and classes.

Probabilistic Fracture Mechanics for Mature Service Frame Rotors

2021 ◽  
Author(s):  
Philipp Engels ◽  
Christian Amann ◽  
Sebastian Schmitz ◽  
Kai Kadau
Keyword(s):  
Fracture Mechanics ◽  
Probabilistic Approach ◽  
Three Dimensional ◽  
Design Tools ◽  
Simulation Design ◽  
Probabilistic Fracture Mechanics ◽  
Service Business ◽  
Heterogeneous Nature ◽  
Turbine Disks ◽  
Turbine Design

Abstract Large gas turbine design and service business are challenged with increased demands towards flexible operations, increasing number of start-stop cycles and intermediate cycles. Probabilistic fracture mechanics (PFM) simulation design tools have matured and became robust and reliable. We present a probabilistic re-evaluation of Siemens E-class turbine disks by the combination of probabilistic two-dimensional axisymmetric part analysis of the disk and a novel probabilistic approach for the three-dimensional blade attachment. The first addresses the risk of inherent forging flaws, the latter combines the risk of surface crack initiation, growth and failure. Both models consider the heterogeneous nature of material properties, flaw geometries and detectability. These novel concepts developed at Siemens allow for an optimization of resource usage and safety, as well as the development of new service and inspection concepts for a variety of service frames and classes.

scholarly journals Analysis for Thermal Elasto-Plasticity and Creep of Turbine Disks

1985 ◽  
Author(s):  
Shung Chang-Bing ◽  
Peng Zhi-Yong
Keyword(s):  
Kinematic Hardening ◽  
Hold Time ◽  
Three Dimensional ◽  
Plastic Strains ◽  
Creep Life ◽  
Hardening Rule ◽  
Elasto Plasticity ◽  
Stress Surface ◽  
Turbine Disks ◽  
Plastic Creep

This paper analyzes the thermal elastic-plastic-creep at the bottom of slots in turbine disks using three-dimensional finite elements. Considering the low cycle of engine parts during takeoff-operating-landing process, the yield stress surface of the material is treated according to the kinematic hardening rule. Since the plastic strains are caused by transient loads when starting the engine, being time-independent, while the creep strains are caused by hold time and large loads under high temperature, being time-dependent, the calculation is performed for these two cases, respectively. This would be more correspondent to the practical states of engine. The computation results show that the creep of turbine disks is under neither constant stresses nor constant strains, but is under the combination of both. This phenomenon brings forward a new concept to predict the fatigue/creep life of turbine disks.

Effect of Ingress on Turbine Disks

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
GeonHwan Cho ◽  
Carl M. Sangan ◽  
J. Michael Owen ◽  
Gary D. Lock
Keyword(s):  
Three Dimensional ◽  
Rotating Disk ◽  
Disk Surface ◽  
Temperature History ◽  
Ir Sensors ◽  
History Of ◽  
Turbine Disks ◽  
Thermal Buffering ◽  
Adiabatic Effectiveness ◽  
Semi Empirical

The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the seal. This paper describes experimental measurements which quantify the effect of ingress on both the stator and rotor disks in a wheel-space pressurized by sealing flow. Infrared (IR) sensors were developed and calibrated to accurately measure the temperature history of the rotating disk surface during a transient experiment, leading to an adiabatic effectiveness. The performance of four generic (though engine-representative) single- and double-clearance seals was assessed in terms of the variation of adiabatic effectiveness with sealing flow rate. The measurements identify a so-called thermal buffering effect, where the boundary layer on the rotor protects the disk from the effects of ingress. It was shown that the effectiveness on the rotor was significantly higher than the equivalent stator effectiveness for all rim seals tested. Although the ingress through the rim seal is a consequence of an unsteady, three-dimensional flow field, and the cause–effect relationship between pressure and the sealing effectiveness is complex, the time-averaged experimental data are shown to be successfully predicted by relatively simple semi-empirical models, which are described in a separate paper. Of particular interest to the designer, significant ingress can enter the wheel-space before its effect is sensed by the rotor.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

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