| 1. |
- Busse, Christian, et al.
(författare)
-
A FINITE ELEMENT STUDY OF THE EFFECT OF CRYSTAL ORIENTATION AND MISALIGNMENT ON THE CRACK DRIVING FORCE IN A SINGLE-CRYSTAL SUPERALLOY
- 2016
-
Ingår i: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2016, VOL 7A. - : AMER SOC MECHANICAL ENGINEERS. - 9780791849835
-
Konferensbidrag (refereegranskat)abstract
- The elastic and plastic anisotropy of the single-crystal materials bring many difficulties in terms of modeling, evaluation and prediction of fatigue crack growth. In this paper a single-crystal material model has been adopted to a finite element-environment, which is paired with a crack growth tool. All simulations are performed in a three-dimensional context. This methodology makes it possible to analyze complex finite element-models, which are more application-near than traditional two-dimensional models. The influence of the crystal orientation, as well as the influence of misalignments of the crystal orientation due to the casting process are investigated. It is shown that both the crystal orientation and the misalignment from the ideal crystal orientation are important for the crack driving force. The realistic maximum limit of 10 degrees misalignment is considered. It can be seen that crack growth behavior is highly influenced by the misalignment. This knowledge is of great interest for the industry in order to evaluate the crack growth in single-crystal components more accurately.
|
|
| 2. |
- Gutierrez Salas, Mauricio, et al.
(författare)
-
Forced response analysis of a mistuned compressor blisk comparing three different reduced order model approaches
- 2016
-
Ingår i: Proceedings of the ASME Turbo Expo. - : ASME Press. - 9780791849835
-
Konferensbidrag (refereegranskat)abstract
- Accurate structural modeling of blisk mistuning is critical for the analysis of forced response in turbomachinery. Apart from intentional mistuning, mistuning can be due to the manufacturing tolerances, corrosion, foreign object damage and in-service wear in general. It has been shown in past studies that mistuning can increase the risk of blade failure due to energy localization. For weak blade to blade coupling, this localization has been shown to be critical and higher amplitudes of vibration are expected in few blades. This paper presents a comparison of three reduced order models for the structural modeling of blisks. Two of the models assume cyclic symmetry while the third model is free of this assumption. The performance of the reduced order models for cases with small and large amount of mistuning will be examined. The benefits and drawbacks of each reduction method will be discussed.
|
|
| 3. |
- Leidermark, Daniel, et al.
(författare)
-
COMPARATIVE ANALYSIS OF STRESS RELAXATION AND CREEP IN A SINGLE-CRYSTAL SUPERALLOY
- 2016
-
Ingår i: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2016, VOL 7A. - : AMER SOC MECHANICAL ENGINEERS. - 9780791849835
-
Konferensbidrag (refereegranskat)abstract
- The creep response of the single-crystal nickel-base super alloy MD2 has been investigated in this study. A set of constant load creep experiments was performed loaded in the nominal [001], [011] and [111] crystal orientations. A crystal plasticity. - creep relaxation model, based on thermomechanical fatigue stress relaxation tests, was benchmarked to simulate the creep behaviour. The responses from the model were then compared to the results obtained during the creep tests. From the comparison it could observed that a trend for the [001] crystal orientation is present. A relative creep response between the simulations and experiments could be observed for the different stress levels. At high and increasing stress levels the relative relation is increasing. Under a certain stress level the relative relation is instead increasing for decreasing stress levels. This relative relation arises from the stress relaxation evaluation process, in which the creep parameters are defined, presumably due to the high stress relaxation that is present in the initial time frame. No trend was seen for the [011] and [111] crystal orientations. A discrepancy between the simulations and experiments was still obtained, also related to the high stress relaxation of the initial time frame.
|
|
