Optimisation of the Ektorp sofa frame through the use of Finite element analysis

Abstract:

The interest in using finite element analysis (FEA) as a product development tool is present within IKEAof Sweden (IoS). To gain additional support from within IoS a project was issued to identify the meritsand demerits of FEA. This was done by applying FEA to optimise an existing product, namely theEktorp sofa frame. Three important questions are addressed in this report:

• How can the finite element method efficiently and reliably be applied to improve an existingproduct?

• What types of improvements can be anticipated from using the finite element method andhow can these be achieved?

• What products are suitable to be developed with the use of FEA?

As the sofa frame mainly consists of wood a literature study is conducted to answer several questionsregarding the use of wood in conjunction with FEA. Real life tests are performed to verify acquiredmaterial data.

The original design is analysed with FEA to act as reference for newer concepts and also to identifyareas of improvement. Additional design tools are also applied to complement the FEA.

Concepts are generated to improve a number of factors such as weight, number of components andcost. These concepts are analysed with FEA to be compared to the original design and incrementallychanged until meeting set requirements.

A final concept where the cost, weight and number of components are reduced is thoroughlydescribed and presented as a CAD model. The final result is the Ektorp sofa frame with its weightreduced by 10.9%, number of components reduced by 18.2% and material cost reduced by 13.4%.

The conclusion from this process is that FEA can efficiently and reliably be applied to improve anexisting product. This, however, requires thorough knowledge in FEA. Strength, weight and cost arethe most obvious factors that can benefit from the use of FEA while almost all design changes canbenefit indirectly as well. Almost any product can benefit from the use of FEA; however, severalfactors decide the efficiency and reliability of these analyses, such as analysis experience and productcomplexity.