Takeshi Takatoya

Design-Informatics Approach for Intimate Configuration of Silent Supersonic Technology Demonstrator

The intimate configuration of the silent supersonic technology demonstrator has been designed using the design-informatics approach. As a first step, multidisciplinary design optimization with multi-objectives has been performed for the wing shape of a silent supersonic technology demonstrator among aerodynamics, structures, aeroelasticity, and boom noise. Aerodynamic evaluation was carried out by solving Euler equations on computational fluid dynamics, and composite structural weight evaluation was performed by using MSC. NASTRAN for strength and flutter requirements on computational structural dynamics. The intensity of sonic boom was evaluated by a modified linear theory. The optimization problem had four objective functions as the minimizations of the pressure drag and the boom intensity at supersonic condition, and the composite structural weight. The intimate configuration defined by 50 design variables was optimized on particle swarm optimization and genetic algorithm hybrid method. In the structural evaluation, the combination optimization of stacking sequences of laminated composites was performed for inboard and outboard wings with strength and flutter requirements. Consequently, 37 non-dominated solutions were obtained. As a second step, data mining has been performed to obtain the design knowledge for deciding a compromise solution. The data mining revealed the knowledge in the design space, such as the tradeoff information among the objective functions, and the correlations between objective functions and design variables. A compromise solution was successfully determined by using the obtained design knowledge. Design-informatics approach is essential for an efficient design process.

In-plane and Out-of-plane Characteristics of Three-dimensional Textile Composites

In an effort to achieve high performance and low cost manufacturing of composite structures, this study focuses on the resin film infusion (RFI) process and the three-dimensional (3-D) textile preform, which consists of in-plane and out-of-plane fibers for the near net-shape. Bismaleimide resin system is selected for the RFI process. In this study, the fundamental properties of 3-D textile composites under room temperature and dry conditions are characterized and compared with those of two-dimensional laminate composites of the same resin system. The 3-D textile composites show 0-13% lower in-plane properties, but 10-47% higher properties for open-hole and impact damage.

Evolutionary-Based Multidisciplinary Design Exploration for Silent Supersonic Technology Demonstrator Wing

Multidisciplinary design exploration with multiple objectives was performed for the wing shape of a silent supersonic technology demonstrator, considering aerodynamics, structures, and boom noise. Aerodynamic evaluation was carried out by solving Euler equations with computational fluid dynamics, and composite structural evaluation was performed by using Nastran for strength and vibration requirements with computational structural dynamics. The intensity of the sonic boom was evaluated by a modified linear theory. The optimization problem had five objective functions: minimization of the pressure and friction drags, boom intensity at the supersonic condition, and composite structural weight and maximization of the lift at the subsonic low-speed condition. The three-dimensional wing shape defined by 58 design variables was optimized with multi-objective particle swarm optimization and an adaptive-range multi-objective hybrid genetic algorithm method. In the structural evaluation, the combination optimization of stacking sequences of laminated composites was performed for inboard and outboard wings with strength and vibration requirements. Consequently, 75 nondominated solutions were efficiently obtained through 12 generations. Moreover, data mining was performed to obtain the design knowledge for deciding a compromise solution. The data mining revealed useful knowledge in the design space, such as the tradeoff information among the objective functions and the correlations between the objective functions and design variables. A compromise solution was successfully determined by using the obtained physical design knowledge.

Multidisciplinary Design Exploration of Wing Shape for Silent Supersonic Technology Demonstrator

Multidisciplinary design exploration with multi-objectives has been performed for the wing shape of a silent supersonic technology demonstrator among aerodynamics, structures, and boom noise. Aerodynamic evaluation was carried out by using Euler computation on computational fluid dynamics, and composite structural evaluation was performed by using NASTRAN for strength and vibration requirements on computational structural dynamics. The intensity of sonic boom was evaluated by a modified linear theory. The optimization problem had five objective functions as the minimizations of the pressure/friction drags and the boom intensity at supersonic condition, and the composite structural weight as well as the maximization of the lift at subsonic condition. The three-dimensional wing shape defined by 58 design variables was optimized on particle swarm optimization and genetic algorithm hybrid method. In the structural evaluation, the combination optimization of stacking sequences of laminated composites was performed for in/outboard wings with strength and vibration requirements, respectively. Moreover, since the result of a multi-objective optimization problem is not a sole solution but an optimum set due to tradeoffs, data mining was performed to decide a compromise solution. Consequently, 75 non-dominated solutions were obtained. The data mining revealed the knowledge in the design space, such as the relations among the objectives, and the correlations among objectives and design variables. A compromise solution was determined through data mining.

A Challenge of Modeling Thermo-Mechanical Response of Silica-Phenolic Composites under High Heating Rates

We have been building up a brand new ablation analysis code which is intended to predict simultaneously thermo-chemical and thermo-mechanical response of the SilicaPhenolic (SiFRP) ablator. In this paper, the model is applied to the RTG tests, FTE tests and the laser heating tests for model validation. The comparison to the SiFRP’s actual thermomechanical behavior shows that the present model gives better match by introducing the dependence of the elastic coefficient on the pore pressure in the high temperature region.

Design-informatics approach applicable to real-world problem

The design-informatics approach has been proposed for next-generation innovative design methodology. The multi-objective problem should be treated in a real-world engineering problem because of the various design requirements. When a multi-objective optimization is implemented, the obtained result is not a sole solution but a set of optimum solutions due to tradeoff relations among design requirements. Therefore, decision-making process is necessary as a post-process for optimization result. In the present study, the design-informatics approach, which is considered as a sequential process between an optimization and its post-process operations, is suggested and is applied to the large-scale and real-world design problem. Consequently, a compromised solution can be efficiently decided from the non-dominated solutions obtained by multidisciplinary design optimization. This approach would be a new efficient procedure for design manner, and also it would be the methodology that innovative design knowledge can be acquired.

Static Aeroelastic Analysis of Experimental SST NEXST-1 Flight Test using Wing-Body Configuration Model

Flight test of JAXAs non-powered scaled supersonic experimental airplane, NEXST-1, was successfully conducted on 10 October 2005. The wing shape of this airplane was designed at a specific flight condition whereas an aeroelastic wing shape varies at each flight condition depending on aerodynamic load. In order to predict accurate aeroelastic shapes and aerodynamic characteristics for each flight condition, the fluid-structure interaction analysis method of CFD and FEM was developed. In addition to this wing deformation, the fuselage deformation is required to be considered because the attack of angle measurement system is set near the nose. Comparison between the solution by this analysis and actual data acquired during the flight test was conducted, and also effect of the aeroelastic wing deformation on the aerodynamic characteristics was investigated and reconsidered for verifying the validity of our design.