Tolerance management during the design of composite structures considering variations in design parameters

Composite structures play an important role in realising resource-efficient products. Their high lightweight potential and improved manufacturing technologies lead to an increased use in high-volume products. However, especially during the design and development of high-volume products, the consideration of uncertainties is essential to guarantee the final product quality. In this context, the use of modern lightweight materials, such as fibre reinforced plastics (FRP), leads to new challenges. This is due to their high number of design parameters, which are subject to deviations from their nominal values. Deviating parameters, e.g. ply angles and thicknesses, influence the manufacturing process as well as the structural behaviour of a composite part. To consider the deviating design parameters during the design process, a new tolerance optimisation approach is presented, defining tolerance values for laminate design parameters, while ensuring the functionality of the composite structure. To reduce the computational effort, metamodels are used during this optimisation to replace finite element simulations. The proposed approach is applied to a use case with different key functions to show its applicability and benefits.

Design of a Smart Morphing Wing Using Integrated and Distributed Trailing Edge Camber Morphing

In this study, the design and development of an autonomous morphing wing concept were investigated. This morphing wing was developed in the scope of, the Smart-X project, aiming to demonstrate in-flight performance optimisation. This study proposed a novel distributed morphing concept, with six Translation Induced Camber (TRIC) morphing trailing edge modules, inter-connected triangular skin segments joined by an elastomer material to allow seamless variation of local lift distribution along the wingspan. An FSI structural optimisation tool was developed, to achieve this optimised design, and to produce an optimal laminate design of fibre Glass weave material, capable of reaching target shapes and minimise actuation loads. Analysis of the kinematic model of the embedded actuator was performed, and a conventional actuator design was selected to continuously operate at the required load and fulfil both static and dynamic requirements in terms of bandwidth, actuation force and stroke. Preparations were made in this study for the next stage of the Smart-X design, to refine the morphing mechanism design and build a functional demonstrator for wind tunnel testing.

Study of Mechanical Properties of Hemp Fiber Composites for Electric Bicycle Frames

Electric bicycles are one of the two-wheeled transportation that has been widely used. The structure of the bicycle is generally composed of several components, one of which is the frame. The frame serves to support the load on the bicycle. At present, many changes in design, geometry and bicycle-forming materials have been carried out. In general, bicycle frames are made of metal and alloy because they have good strength to support the load of the driver. Lately, the use of composites has begun to develop as a bicycle frame material, because the frame of the bicycle has become lighter but still has the strength to support the load. This paper presents a study of the structure of electric bicycles using composite material based on epoxy matrices with rami fiber reinforcement. This study used an experimental and simulation method by designing composite laminates with A(90o/90o/90o), B(90o/45o/90o), and C(45o/45o/45o) fiber webbing layout and then carried out free compressive strength (UCS), optical microscopy and simulation using ANSYS 19.0 software. The results obtained are composite laminate design with a woven fiber layout (45o/45o/45o) having the highest strength value with a compressive stress value σ=58.64 MPa in the axial compressive plane, and σ=1.539 MPa in the tangential compressive plane. Likewise, the simulation results also obtained the highest strength in the webbing design (45o/45o/45o) which is equal σs=58.72 MPa in the axial compressive plane and σs=1.531 MPa in the tangential compressive plane.