Research Areas

Our research group concentrates on topics for which the permanent staff has acquired an international reputation, and in which fundamental and strategic research of high quality can be carried out. Typically, our research projects combine engineering expertise in the field of the subject matter with the use of advanced computational tools in order to develop design solutions relevant to industrial needs. The final product of research can be a scaled prototype of an innovative technology or computer software for use in the industry. The following topics are areas of application of our research.

1. Tailored Structures

Optimal stiffness and strength design of structural components made of conventional metallic and/or fiber reinforced composite materials, through carefully calculated distribution of material and other physical properties to improve structural response related to vibration, buckling, postbuckling, and weight characteristics. Development of multi-level optimization and structural shape, topology, and layout optimization procedures. Inclusion of fabrication, such as use of advanced fiber- and tow-placement technologies in design tailoring of fiber reinforced composite structures.

2. Adaptive and Smart Structures

Design and optimization of actively sensed and actuated smart structural systems that incorporate adaptive materials such as piezoelectric and shape memory alloy devices to affect their shape and response characteristics to adapt to changing mission requirements and environmental conditions with minimum energy requirements. Development of novel concepts for multifunctional structures, and use of self-healing materials for reliable structures.

3. Structural Optimization

In engineering design problems one can use topology design amd material optimization. Optimal structures are generally unstable, therefore the complete picture of all loading conditions has to be looked at. Structures should be effective but stable. Analytical tools are being developed, and the large Finite Element Method based codes available by the chair are used.

4. Design Oriented Analysis of Composite Structures

Analytical and computational modeling of composite panels and shells under multiple loadings for automotive, helicopter, and passenger aircraft applications. In particular, fast analysis tools for stiffened and unstiffened panels under compression loads, novel structural configurations that have multiple concentric layups and grid stiffened composite structures for fuselage applications. Among the problems that are currently being studied are the analysis of skin-stiffened panels at stiffener termination locations, and design of improved crash absorbing composite structures.

5. Multi-scale material simulation

The optimization of the material performance at the engineering (macro) scale is accomplished by adapting its underlying microstructure. For the performance of high-fidelity simulations of complex engineering systems, an adequate connection between the micro-, meso-, and macro scales needs to be established. This can be done using so-called multi-scale methods, such as multi-scale algorithms for coupled nonlinear, multiple time/spatial scale PDE systems, subgrid-scale modeling, and methods for coupling discrete and continuum models. Essentially, the main challenge of multi-scale modeling is to accurately represent the relevant physical scales in a simulation without running into unacceptable computational times and large memory requirements.

6. Stability and Vibrations of Shells

Theoretical, numerical, and experimental studies of the collapse and vibration behavior of imperfect composite shells under combined loading. Emphasis is on cylindrical and conical shells, representative of fuselage, tail-cone, and launch vehicle components. Development of the Delft Interactive Shell DEsign COde (DISDECO) and an International Imperfection Data Bank.

7. Failure analysis of structural and functional materials

The demand of new high-performance materials in aerospace applications requires increasingly sophisticated methods to analyze the multi-physics processes controlling the structural response. These methods involve the coupling of multiple physical models or multiple simultaneous physical phenomena. Such methods can be applied, for example, to study the thermo-chemo-mechanical performance of a broad range of functional materials, such as thermal-barrier coatings and functionally-graded materials, and structural materials such as composites and high-strength, high-ductility metals.

8. Thermal Loading of Structures

Numerical (FEM) modeling of nonlinear transient thermo-mechanical and structural behavior of space re-entry structures, thermal protection systems, and integrated hot-structures. Development of thermal test facility and combined experimental/numerical verification of thermo-structural design problems.

9. Inflatable Structures

Mechanics of inflatable structural components made of thin membranes, such as tubular and torroidal members, and their design methods for the development of light-weight low-storage-volume deployable structures.

10. Aircraft Crashworthiness

Design and optimization of air vehicle structures to improve damage response and structural integrity, thereby enhancing their safety and survivability, under crash conditions that lead to large nonlinear deformations and material nonlinearities.