3C: Ultra-Lightweight Trailer Design


This project will explore the benefits to be realised by using composite materials in the context of new trailer axle steering technologies which enable novel arrangements of axles and substantially reduce frame loads and reduced underbody drag on trailers.

Reducing trailer side loads by using steerable wheels provides an opportunity to change the configuration of axles and break out of the traditional paradigm of long wheel-base beam-type structures. Reducing drag by improved under-body aerodynamics requires introduction of new panels. A composite trailer can combine aerodynamic and structural functions, leading to significantly reduced weight with improved performance. For example the ROADLITE 10 m trailer showed a 400 kg weight saving over a comparable steel trailer. This used a monocoque design with vacuum-infused GFRP [1]

It is believed that this approach can be taken much further by allowing axle layouts to be optimised simultaneously with the structural design and use of new hybrid material systems (novel sandwich structures, etc). However introduction of smaller elements within the structure, akin to the staged introduction of composites into aircraft, may be a more practical approach. Hence the focus of the project will be in two areas, adopting a ‘clean slate’ approach for the whole trailer and identifying composite solutions for specific components.

Objectives

(i) Identify and develop composite design solutions for appropriate trailer components
(ii) Develop a novel design approach for the overall chassis which incorporates the structural and aerodynamic requirements.
(iii) Target a 20% reduction in trailer mass, which is expected to generate up to 5% lower vehicle fuel consumption per freight task.
(iv) Provide an algorithm to model the effects of various trailer light-weighting strategies for incorporation into the decarbonisation quantification tool, Project 2B.

Programme and Deliverables

Project Tasks

Task 3C1. Survey of existing composite use. Identification of appropriate service vehicles, for example specialist urban delivery vehicle or convenience store 10 m trailers where some extra cost might be absorbed. Definition of appropriate target structures, for example the whole chassis and/or sub-components such as fairings for the under-body, tail gate, barn doors. (Cambridge and industrial partners).

Task 3C2. Structural optimisation methodology (Cambridge and industrial partners). A methodology for design and structural optimisation will be adapted from the database-driven optimisation method developed in Cambridge [2] for composites structural design. The methodology can include manufacturing and structural constraints and will allow evaluation of the trade-off between design complexity, mass, cost and fuel savings, aerodynamic features and novel wheel configurations. Input from industry partners will help quantify the relative importance of these aspects. For the chassis we will allow comparison of a ‘functional’ design (separate load-bearing and aerodynamics components) with an integrated shell design of a range of materials and layups, including an entirely monocoque structure or including pultruded stiffeners in key locations. The component studies will compare traditional and composite solutions.

Task 3C3. Design solution (Cambridge). We will use the design methodology developed in Task 3C1 to design a small number of candidate trailers and components. The algorithms used to quantify the benefits and trade-offs will be adapted for incorporation into the decarbonisation quantification tool, Project 2B. Detailed design of critical parts (e.g. suspension, joints) will adopt standard industry solutions where possible.

Deliverables

The work will result in: (i) a methodology to design against competing requirements, (ii) practical design solutions, (ii) demonstrator components with quantified benefits.

Impact

Academic Impact: We will provide a framework for academics and practitioners to address lightweight design of trailers, including interactions between the structural and construction aspects of the design, integration of the demands of underbody aerodynamics and the opportunities for alternative wheel layouts incorporating active steering.

Commercial and social Impact: The research will quantify the benefits of radical use of composites in trailers, include this quantification in a decarbonisation quantification tool, and demonstrate their use in practical applications.  Light-weighting of the trailer delivers direct societal impact in reduced fuel consumption and hence CO2 emissions via reduced energy for acceleration, hill climbing and reduced rolling resistance.

References

1.         Turner, M. and G. Boyce, ROADLITE – Manufacture of a lightweight, cost effective, polymer composite road trailer, in Proc JSAE Annual Congress. 2005

2.         Monroy Aceves, C., et al., Design methodology for composite structures: a small low air-speed wind turbine blade case study. Materials and Design, 2012 36:296-305