The Department of Aerospace Engineering at Iowa State University (www.aere.iastate.edu) invites applicants for faculty positions in each of the broad areas of Computational Propulsion, Thermal Management & Heat Transfer, and Experimental Robotics & Autonomous Aerospace Systems. Applications are sought for tenured and tenuretrack appointments at the level of Assistant or Associate Professor, and exceptional candidates who qualify for the rank of Full Professor may also be considered for the Dennis and Rebecca Muilenburg Chair in Aerospace Engineering.

A software tool for automated crack onset and growth simulations based on the eXtended Finite Element Method (X-FEM) has been developed. For the first time, this tool is able to simulate arbitrary crack growth and composite delamination without remeshing. The automated tool is integrated with Abaqus/Standard and Abaqus/CAE via the customization interfaces. It seamlessly works with the Commercial, Off-The-Shelf (COTS) Abaqus suite.

The relationships between a resistance curve (R-curve), the corresponding fracture process zone length, the shape of the traction/displacement softening law, and the propagation of fracture are examined in the context of the through-the-thickness fracture of composite laminates. A procedure that accounts for R-curve toughening mechanisms by superposing bilinear cohesive elements is proposed. Simple equations are developed for determining the separation of the critical energy release rates and the strengths that define the independent contributions of each bilinear softening law in the superposition. It is shown that the R-curve measured with a Compact Tension specimen test can be reproduced by superposing two bilinear softening laws.

ILC Dover, under contract by NASA Langley Research Center, and in cooperation with NASA Johnson Space Center is designing and manufacturing an expandable lunar habitat. This cylindrical habitat, or Engineering Development Unit (EDU), is a hybrid system with two hard end caps and a deployable softgoods section in the center. The softgood section packs into the endcaps and the unit roughly doubles in length upon deployment. The EDU is designed to demonstrate packing and deployment of an expandable habitat under expected loading conditions. Using a unique fabric lobe system, the structure is intended to be lighter in weight with a higher volume than a similar metal configuration. The restraint layer uses a webbing net construction with a coated fabric to carry the pressure loads up to 9 psi.

An Abaqus/Standard FEA based study was carried out to develop a structural format for a wing sail used on a sailing boat, V-39 Albatross. As well as providing a novel structural solu-tion to meet a challenging set of requirements, the study has given the necessary mass properties and stiffness data required to further progress the preliminary design phase of the overall boat. The brief for the boat is to set a new world outright sailing speed record at Portland, UK. The choice of location influences the overall concept from the outset, since the conditions are closer to real world conditions when compared to currently favored locations for speed sailing. The boat is configured to add at least 10 knots to the current record by setting a speed above 60 knots (111 km/h).

An analysis of the crippling test applied to thin profiles is considered in this paper by using a standard tension test machine. Crippling tests are compression tests leading to crush collapse. This kind of tests cannot be properly performed in the standard test machine because of an inefficient transmission of the compression load to the specimen. To accomplish a more accurate test an improvement device is designed and modelled. This proposed device consists of four symmetrically-arranged guides joining the two machine heads. The head rotation is thus avoided during the test and the compression load is transmitted to the profile without introducing bending effects through the heads.

The ability to accurately model welding processes in order to predict residual stresses and distortions is becoming increasingly important in the engineering industry. Abaqus can be used to model the welding process but this has been found to be considerably time consuming and requires a large number of assumptions to be made. Virtual Fabrication Technology is an analysis software suite that is designed to allow Abaqus to accurately model complex welding procedures. It was developed by the Battelle Memorial Institute in conjunction with Caterpillar Incorporated in the USA. The software is centred on a Graphical User Interface that is used to assign welding paths, parameters and material properties to FE models that have been imported from Abaqus/CAE.

A unified framework is presented that enables coupled multiscale analysis of composite structures and associated graphical pre and post processing within the Abaqus/CAE environment. The recently developed, free, Finite Element Analysis - Micromechanics Analysis Code (FEAMAC) software couples NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) with Abaqus/Standard and /Explicit to perform micromechanics based FEA such that the nonlinear composite material response at each integration point is modeled at each increment by MAC/GMC.

Finite element analysis (FEA) of a composite overwrapped pressure vessel (COPV) has traditionally been a tedious and time consuming task. FEA is often omitted in the development of many vessels in favor of a “build and burst” philosophy based only on preliminary design with netting analysis. This is particularly true for small vessels or vessels that are not weight critical. The primary difficulty in FEA of a COPV is the creation of the model geometry on the sub-ply level. This paper discusses employing a commercially available tool to drastically reduce the time required to build a COPV FEA model. This method produces higher fidelity models in only slightly more time. Analysis results are presented along with comparisons to burst test data.

Turon’s methodology for determining optimal analysis parameters for the simulation of progressive delamination is reviewed. Recommended procedures for determining analysis parameters for efficient delamination growth predictions using the Abaqus/Standard cohesive element and relatively coarse meshes are provided for single and mixed-mode loading. The Abaqus cohesive element, COH3D8, and a user-defined cohesive element are used to develop finite element models of the double cantilever beam specimen, the end-notched flexure specimen, and the mixed-mode bending specimen to simulate progressive delamination growth in Mode I, Mode II, and mixed-mode fracture, respectively. The predicted responses are compared with their analytical solutions.

Structures in general are subject to uncertainty due to manufacturing, assembly, environment of work, loads, etc … This scatter more specifically is associated for example to tolerances of thickness, position, waviness, etc, material mechanical properties distribution, layup alignment axes. All these deviations can be taken into account with stochastic analysis to reduce the total cost of the project considering all the phases of product life (manufacturing, assembly, maintainability…) and make a global robust design.

Thermal Barrier Coatings (TBC) have been used for almost three decades for heat insulation in high-temperature components to increase efficiency. Reliable diagnostic techniques that are practical to implement are needed to identify the location and severity of degradation in TBCs to protect against premature TBC failure. Luminescence spectroscopy has been utilized in detecting early damage, as it exhibits monotonic changes in the spectral characteristics with damage. Nevertheless there is still no agreement on what are the best spectral parameters that indicate damage. A new Finite Element model is presented, which is used to make realistic predictions of TBC lifetime, from as-manufactured to critically damaged.

Bird impact damage in complex aircraft structure has been investigated using explicit transient dynamic analysis by Abaqus/Explicit in order to fully employ its large library of elements, material models and the ability of implementing user defined materials. The numerical procedure has been applied on the very detailed large airplane secondary structure consisting of sandwich, composite and metallic structural items that have been modeled with 3D, shell and continuum shell elements, coupled with appropriate kinematic constraints. Bird has been modeled using Coupled Euler Lagrangian approach, in order to avoid the numerical difficulties connected with the mesh. The impact has been applied in the area that is the most probably subjected to the impact damage during the exploitation.

Innovative composite structures are increasingly being used in the aircraft industry. A critical point of these new composite parts is the attachment to the surrounding aircraft structure. In cooperation between different EADS Business Units, a new advanced composite load introduction rib is developed to minimize weight and manufacturing costs. The new design of the flap focuses on the load introduction rib and drive fitting including the integrated lugs for the attachment to the flap support structure. The calculation of composite load introduction requires the implementation of 3D elements for an accurate analysis of all stress components.

Boeing and Skyhook International entered into an agreement whereby Boeing will design and build two prototypes of the new Skyhook HLV aircraft. This hybrid airship is intended to carry 40 tons of cargo 100 miles. Due to the flexible, non-linear nature of fabric airship envelopes, as well as the complexity of designing a hybrid airship, the internal loads model for this aircraft is being developed in Abaqus and will be solved non-linearly. Additionally, certain key technologies within Abaqus are being used in the early stages of aircraft development to help speed up the design process and improve accuracy.

TENURE-TRACK FACULTY POSITION: The Department of Aerospace Engineering at Iowa State University invites applicants for a faculty position in the area of autonomous space systems. The appointment will start in August 2011. The search is focused at the Assistant and Associate Professor level, but exceptional candidates who qualify for the rank of Full Professor will also be considered. The primary research interests include robotic and human space exploration, on-board autonomy, and space systems analysis, with background in the disciplines of adaptive guidance and control, navigation, and space flight mechanics. A balanced research program with a strong experimental interest is desirable. An earned Ph.D.

Hello,

I am looking for any resource where I can get some data regarding the average force and its time variation with which the wind applies force onto an aircraft body especially the wing. To reframe the question in a better way: can anyone recommend a resource that has data about the wind velocity profile around the aircraft (especially the wings) or pressure/shear force profile on the boundary of the aircraft (especially the wings) during various phases in its flight. 

My focus is any aircraft type similar to B737, but anything even vaguely related will be of great help.

I will really appreciate if anyone in this community can help me with this.

Thanks,

Sourish

Hi Friends,

Iam looking for PhD positions in Composites Mechanics and Manufacturing area.

If you happen to know any information, kindly convey it to me.

Please find my Resume attached for your information.

Thanks and Regards,

Thiyagarajan Dev,

India