Holistic view and optimization of sandwich panel joints in the aircraft cabin

Motivation

In aircraft cabin monuments, there is a high variety of different load application points due to technical and customer-specific requirements. There is great potential for optimization, as current research usually only provides further isolated solutions and a holistic view is missing. In application, there is a lack of standards and identical requirements can produce a variety of designs and production methods.  A database of existing solutions as a decision-making guide for modifications and new developments, general design guidelines for load-path-optimized interfaces and a consistent design, layout and production process do not exist. The resulting variants of designs and production methods in practice make process optimization and, in particular, automation more difficult. Furthermore, highly loaded attachments are currently realized with hard fabric inserts. These are usually overdimensioned and do not conform to lightweight design, since the load distribution is unsteady and there is a stiffness jump to the honeycomb core, which leads to premature failure.

Objective

The aim of the project is to create a holistic, digitalized development and production process for the simulation-based design and digital production of load introduction points.

The goal of the Hamburg University of Technology in the CabinJoint project is the numerical optimization and automated production of load introduction points in sandwich components.

The goal of the Institute of Product Development and Mechanical Engineering Design is to integrate simulation models into the process chain in order to support the development and manufacturing of load introduction points with a methodical approach. The analysis of the models enables a reduction of the design variants to the optimal solution according to the application. Furthermore, numerical optimizations will be applied to develop load path optimized designs for highly loaded sandwich panel joints by means of numerical optimizations in order to reduce the weight. In addition, the use of virtual testing will be analyzed. This can greatly reduce the approval effort, as validated models can reduce practical load testing, allowing the use of individually optimized load application points in the first place.

Research Method

A holistic, methodical design and engineering process for the optimization of lightweight joining elements is being developed, enabling more efficient, digital development of new inserts and attachments, as well as modification with regard to individual customer requirements, taking into account manufacturing constraints and approvability.
In order to reduce the overall weight of highly loaded sandwich panels, the hard fabric inserts commonly used to date are to be replaced by individually manufactured inserts that realize a suitable continuous load distribution. In order to optimize the highly loaded joints, simulation models will be set up and initial load path analyses will be performed.  Subsequently, load path optimizations are carried out. Based on the results, various load path optimized load introduction points are manufactured and tested. From the results, design guidelines and a methodical procedure for the construction and design of joining techniques are derived.
Furthermore, virtual testing of the joint elements is investigated. To enable a reduction of the testing effort, virtual testing of modified interfaces based on the original validated test model is analyzed.