18 Sep Abaqus for dummies: Mechanics of Aircraft Trailing Edge Flap

Abaqus to study the mechanics of flaps

Welcome to our latest blog post, where we delve into the intricate mechanics of aircraft trailing edge flaps. Understanding the geometry and interactions of these components is crucial for enhancing the aerodynamic performance and lift of an aircraft. In this post, we will explore the detailed configuration and functioning of a three-flap system, examine the model interactions, and discuss the results of our analysis. Join us as we break down the complex mechanisms that enable smooth and efficient flap deployment, contributing to the overall efficiency and safety of modern aviation.

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Let’s continue the blog series dedicated to exploring the vast capabilities of Abaqus.
For engineers, researchers, and enthusiasts alike, Abaqus stands as a beacon of innovation, empowering users to simulate and analyze complex mechanical behaviors with unparalleled accuracy. However, navigating through its extensive features and functionalities can sometimes feel daunting.
In this series, we aim to demystify Abaqus by breaking down example problems into digestible segments, allowing you to grasp its essence and harness its full potential. Whether you’re a novice seeking to enhance your skills or a seasoned professional looking to delve deeper, this series will cater to your needs.
Each blog post will delve into a specific example problem, we will look at some animations and discuss the analysis. Through this series, our goal is not only to showcase the capabilities of Abaqus but also to inspire creativity and foster a deeper understanding of finite element analysis concepts. We encourage active participation, questions, and feedback from our readers, as together, we embark on this educational journey.

Trailing edge geometry and corresponding Abaqus model

The trailing edge flap mechanism is a vital component of an aircraft, significantly influencing its lift and overall aerodynamic performance.
In this example, the trailing edge flap structure comprises three flaps: BASE (yellow), MIDFLAP (purple), and ENDFLAP (orange), as shown in the picture below.. These flaps are interconnected by rigid links, referred to as arms, which are pinned to the flaps at various points. The model includes nine arms: ARM AB, ARM BF, ARM DEFG, ARM EI, ARM HIM, ARM JK, ARM MLJ, ARM NK, and ARM PO. BASE, MIDFLAP, and ENDFLAP are represented as display bodies, while the arms are modeled as rigid truss members. MIDFLAP and ENDFLAP are deployed by rotating ARM AB, which is pinned to BASE at point A.

Trailing edge Abaqus multibody connections

The bodies in the picture below are connected as follows:
JOIN connector elements attach the arms to BASE, MIDFLAP, and ENDFLAP at their endpoints. In some instances, arms are connected to other arms rather than directly to the flaps. Specific connections include:
– ARM AB connects to ARM BF at point B.
– ARM BF and ARM EI connect to ARM DEFG at points F and E, respectively.
– ARM EI and ARM MLJ connect to ARM HIM at points I and M, respectively.
– ARM MLJ connects to ARM JK at point J and to MIDFLAP at point L, which is not an endpoint of ARM MLJ.
LINK connector elements rigidly fix the pivot points on the flaps. These connectors, named LINK GL, LINK GN, LINK GP, LINK KO, LINK LN, and LINK LP, are crucial for supporting BASE, MIDFLAP, and ENDFLAP as these flaps are modeled as display bodies rather than deformable or rigid bodies. Specifically:
– LINK GL, LINK GN, LINK GP, LINK LN, and LINK LP position points G, L, N, and P on MIDFLAP.
– LINK KO positions points K and O on ENDFLAP.
To deploy the flap, BASE is fixed in space by securing points A, D, and H, and ARM AB is rotated 90 degrees about point A. One analysis also models the effects of plasticity in some of the connectors.

Trailing edge Abaqus

The rotation of ARM AB facilitates the deployment of MIDFLAP and ENDFLAP. The figures below present a series of illustrations depicting the positions of the flaps at the start and end of the analysis, as well as at various intermediate stages.

Trailing edge flap mechanism Abaqus reference

This blog post is based on the “Trailing edge flap mechanism” from the Abaqus Example Problem manual. More details can be found here.

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