Analysis of rotating flexible blades using MSC/NASTRAN

An overview is given of the use of MSC/NASTRAN in the analysis of rotating flexible blades. The geometrically nonlinear analysis using NASTRAN Solution Sequence 64 is discussed along with the determination of frequencies and mode shapes using Solution Sequence 63. Items unique to rotating blade analysis, such as setting angle, centrifugal softening effects, and hub flexibility, are emphasized

Structural analysis of low-speed composite propfan blades for the LRCSW wind tunnel model

The Naval Weapons Center at China Lake, CA, is currently in the process of evaluating propulsion systems for the Long Range Conventional Standoff Weapons (LRCSW). At present, the Advanced Counter-Rotating Propfan system is being considered. The methodologies are documented which were used to structurally analyze the 0.55 scale CM1 composite propfan blades for the LRCSW with COBSTRAN and MSC/NASTRAN. Significant results are also reported

Laplacian modes for calorons and as a filter

We compute low-lying eigenmodes of the gauge covariant Laplace operator on the lattice at finite temperature. For classical configurations we show how the lowest mode localizes the monopole constituents inside calorons and that it hops upon changing the boundary conditions. The latter effect we observe for thermalized backgrounds, too, analogously to what is known for fermion zero modes. We propose a new filter for equilibrium configurations which provides link variables as a truncated sum involving the Laplacian modes. This method not only reproduces classical structures, but also preserves the confining potential, even when only a few modes are used.Comment: talk presented by F. Bruckmann at Lattice2005 (Topology and Confinement), Dublin, July 25-30, 2005; 6 pages, 4 figures; uses PoS.cl

Yang-Mills streamlines and semi-classical confinement

Semi-classical configurations in Yang-Mills theory have been derived from lattice Monte Carlo configurations using a recently proposed constrained cooling technique which is designed to preserve every Polyakov line (at any point in space-time in any direction). Consequently, confinement was found sustained by the ensemble of semi-classical configurations. The existence of gluonic and fermionic near-to-zero modes was demonstrated as a precondition for a possible semi-classical expansion around the cooled configurations as well as providing the gapless spectrum of the Dirac operator necessary for chiral symmetry breaking. The cluster structure of topological charge of the semi-classical streamline configurations was analysed and shown to support the axial anomaly of the right size, although the structure differs from the instanton gas or liquid. Here, we present further details on the space-time structure and the time evolution of the streamline configurations.Comment: Invited talk presented at the conference "Quark confinement and the hadron spectrum IX", Madrid, Aug 30 - Sept 3, 201

Topological aspects of G2 Yang-Mills theory

Yang-Mills theory and QCD are well-defined for any Lie group as gauge group. The choice G2 is of great interest, as it is the smallest group with trivial center and being at the same time accessible to simulations. This theory has been found to have many properties in common with SU(3) Yang-Mills theory and QCD, permitting to study the role of the center. Herein, these investigations are extended to topological properties of G2 Yang-Mills theory. After giving the instanton construction for G2, topological lumps with instanton topological charge are identified in cooled lattice configurations. The corresponding topological susceptibility is determined in the vacuum and at low and high temperatures, showing a significant response to the phase structure of the theory.Comment: 13 pages, 6 figures, 1 tabl

Farm Level Risk Assessment Using Downside Risk Measures

Recent and presumable future developments tend to increase the risk associated with farming activities. This causes an increasing importance of risk management. Farmers have a wide variety of possibilities to influence the risk exposure of their operations. Among them are the choice of the production program as well as marketing activities including forward pricing and hedging with futures and options. In total all these opportunities comprise a portfolio of activities which must be selected as to match the resources of the farm as well as the farmer's attitudes towards risk. The paper addresses this issue using a whole farm stochastic optimisation approach based on a risk-value framework. The paper starts with a discussion of risk-value models and the relationship between them and the expected utility hypothesis. In the second part the approach is incorporated in a whole farm model that optimizes a portfolio of production activities and risk management instruments. A case study is used to analyse the possibilities and limitations of the approach and to illustrate the effects of yield and production risk on decision making.downside risk, risk management, risk measure, risk-value models, stochastic optimisation, Risk and Uncertainty,

Pseudemys

Number of Pages: 7Integrative BiologyGeological Science

Trachemys

Number of Pages: 17Integrative BiologyGeological Science

Hub flexibility effects on propfan vibration

The significance of hub flexibility in the nonlinear static and dynamic analyses of advanced turboprop blades is assessed. The chosen blade is the 0.175 scale model of the GE-A7-B4 unducted fan blade. A procedure for coupling the effective hub stiffness matrix to an MSC/NASTRAN finite element model is defined and verified. A series of nonlinear static and dynamic analyses are conducted on the blade for both rigid and flexible hug configurations. Results indicate that hub flexibility is significant in the nonlinear static and dynamic analyses of the GE-A7-B4. In order to insure accuracy in analyses of other blades, hub flexibility should always be considered