Paul M. Weaver

Paul M. Weaver
University of Limerick | UL · Bernal Institute, School of Engineering

PhD

About

451
Publications
162,113
Reads
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10,502
Citations
Introduction
My Group work on stiffness tailoring of composite structures. This often involves encouraging buckling phenomenon to facilitate shape changes, such as in multistable morphing laminates or by exploiting anisotropic properties to minimise weight of more conventional structures. We work closely with aerospace companies, wind turbine blade manufacturers and increasing amounts with the automotive sector.
Additional affiliations
January 1998 - present
University of Bristol
Position
  • Professor in Lightweight Structures
April 1994 - February 1998
University of Cambridge
Position
  • PostDoc Position
Description
  • Worked on Structural shapes selection under MF Ashby to support ongoing work for Cambridge Engineering Selector software

Publications

Publications (451)
Article
Full-text available
The imperfection sensitivity of cylindrical panels under compression loading is shown to be not only reduced but effectively eliminated using stiffness tailoring techniques. Shells are designed with variable angle-tow (VAT) laminae, giving their laminates variable-stiffness properties over the surface co-ordinates. By employing an asymptotic model...
Article
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Emerging manufacturing technologies, including 3D printing and additive layer manufacturing, offer scope for making slender heterogeneous structures with complex geometry. Modern applications include tapered sandwich beams employed in the aeronautical industry, wind turbine blades and concrete beams used in construction. It is noteworthy that state...
Article
This work is a proof-of-concept of the use of azomethine-bearing diamines as novel hardeners of standard epoxy compounds to yield cleavable and thermoformable covalent adaptable networks (CANs), with functional properties otherwise comparable to conventional epoxy networks. A suitable aromatic diamine (TPA-o-PD) was synthesised at acceptable purity...
Article
Full-text available
The design space for high-performance lightweight composite structures has grown considerably since the advent of the variable stiffness concept. In fact, variable stiffness composites have been found to improve buckling performance and dynamic stability, and to tune the structure's dynamic response by tailoring structural stiffness. Thus, in order...
Article
Full-text available
Abstract A novel two-dimensional inverse differential quadrature method is proposed to approximate the solution of high-order system of differential equations. A critical aspect of the proposed scheme is to circumvent the error arising from high sensitivity to noise associated with high-order numerical differentiation operations during direct appro...
Article
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High levels of strength- and stiffness-to-mass ratio can be achieved in slender structures by lengthwise tailoring of their cross-sectional areas. During use, a non-prismatic beam element can be subject to surface forces or loads acting on only a part of their cross-section. Practical examples involve tapered aircraft wings, wind turbine and helico...
Article
An investigation of the effect of strain rate on the dynamic compressive behavior of glass/polytetrafluoroethylene (PTFE) composite is presented. Experimental studies were carried out on two dimensional (2D), satin weave (SW) and three dimensional (3D) woven glass/PTFE composites using split Hopkinson pressure bar (SHPB) apparatus. Commercial grade...
Article
New exact analytical solutions are presented for the static deflection of coupled Timoshenko composite beams resting on two-parameter elastic foundations subject to arbitrary boundary and loading conditions. Governing differential equations are obtained from the principle of virtual work in which four degrees of freedom, namely axial elongation, tw...
Article
Despite their importance in benchmarking numerical simulations, buckling tests still feature compromises between component-level and high-fidelity large-scale tests. For example, compression-induced buckling tests cannot capture the through-thickness or span-wise stress gradients in wing skins. Consequently, the results obtained often require caref...
Conference Paper
Full-text available
View Video Presentation: https://doi.org/10.2514/6.2022-0664.vid Variable-angle tow (VAT) manufacturing methods significantly increase the design space for elastic tailoring of composite structures by smoothly changing the fiber angle and thickness across a component. Rapid Tow Shearing (RTS) is a VAT manufacturing technique that uses in-plane shea...
Conference Paper
Full-text available
View Video Presentation: https://doi.org/10.2514/6.2022-0869.vid Pressure vessels are widely used in a broad range of applications targeting different industries. Therefore, they need to be designed carefully to satisfy the specific design requirements related to each application. Failure performance, weight and packing efficiency are important fac...
Conference Paper
Geometrically nonlinear analysis is essential for characterizing the behavior of nonprismatic beam structures including wings, rotor blades and space antennas that undergo large deflections and rotations in service. Due to inherent flexibility of its kinematics representation, the Unified Formulation (UF) shows excellent capability for efficient de...
Article
Full-text available
Beam-like compliant elements have found wide-ranging application in many fields of engineering and science often where 3D large deflections can be of concern such as soft robotics, DNA mechanics and helicopter/wind turbine rotor blades. The homotopy analysis method (HAM) is used for the first time to obtain a novel analytical solution in converged...
Article
Cylindrical shells under compressive loading are highly sensitive to boundary conditions. Considering that these structures are connected by surrounding structural components with finite stiffness, an accurate evaluation of the effects of their boundary stiffness is crucial in their design. As such, this work investigates the effect of elastic boun...
Article
Thin-walled structures are extensively used in aerospace, automotive and mechanical engineering applications due to their high strength-and stiffness-to-weight ratios. However, the performance of these structures tends to be heavily influenced by localised features such as manufacturing defects or design details included for non-structural reasons,...
Article
Full-text available
New analytical solutions for the static deflection of anisotropic composite beams resting on variable stiffness elastic foundations are obtained by the means of the Homotopy Analysis Method (HAM). The method provides a closed-form series solution for the problem described by a non-homogeneous system of coupled ordinary differential equations with c...
Conference Paper
Cut-outs are inevitable in many structural components such as in aircrafts to accommodate windows or openings for access purposes or fasteners. Engineers usually view cut-outs, especially in primary structures, with disfavour as they result in stress/strain concentration and consequently reduced load carrying capability. Local reinforcements usuall...
Conference Paper
Bamboo poles, and other one-dimensional thin-walled structures are usually loaded under compression, which may also be subject to bending arising from eccentric loading. Many of these structures contain diaphragms or circumferential stiffeners to prevent cross-sectional distortions and so enhance overall load-carrying response. Such hierarchical st...
Conference Paper
The design of a multi-part aerospace structural component, such as a wingbox, is a challenging process because of the complexity arising from assembly and integration, and their associated limitations and considerations. In this study, a design process of a stiffeners-integrated variable stiffness three-bay wingbox is presented. The wingbox has bee...
Conference Paper
Pressure vessels are designed to store liquids and gases and have various applications spanning from chemical plants to automotive and aerospace industries. Currently, lightweight composite pressure vessels are desirable, especially in transportation industry applications because of their subsequent benefits in fuel consumption, cost and environmen...
Conference Paper
With the introduction of the variable stiffness concept, the design space for highperformance lightweight composite structures has expanded significantly. A larger design space, in particular, allows designers to find more effective solutions with higher overall stiffness and fundamental frequency when considering prestressed dynamically excited ae...
Article
Composite materials are gaining increasing interest for design purposes in many industries such as aeronautical and automotive, not only because of their reduced weight, but also due to their enhanced mechanical properties. The heterogeneity inherent in the nature of composites arises not only because of the mismatch in fibre/matrix properties but...
Article
In the present study, abrasive wear tests were conducted to investigate the effect of hygrothermal ageing on the friction and wear resistance of glass/Polytetrafluoroethylene (PTFE) composites. Non-hybrid and hybrid composites were manufactured with PTFE coated two-dimensional plain weave (2D), three-dimensional knitted (3D), satin weave (SW) fabri...
Conference Paper
Pressure vessels are designed to store liquids and gases and have various applications spanning from chemical plants to automotive and aerospace industries. Currently, lightweight composite pressure vessels are desirable, especially in transportation industry applications because of their subsequent benefits in fuel consumption, cost and environmen...
Article
Full-text available
Morphing composite structures are of significant interest due to the fact that they exhibit superior mass-to-stiffness ratios and a large degree of tailorability in comparison to traditional materials and structures. One such morphing composite structure is the multistable composite cylindrical lattice. Current work introduces a novel variable-topo...
Article
Full-text available
Morphing composites are relatively new types of structure that change their shape due to inherent combinations of anisotropy, pre-stress and curvature. They have found use in deployable spacecraft structures, including booms and solar generators. However, little work has been completed on the utilisation of morphing composites in the design of curv...
Article
Heterogeneous materials can show size-dependent behaviour in which the bending modulus depends on sample size. In fibre composite materials the interaction between fibre and matrix can lead to such a size effect.Then the effective modulus calculated by the rule of mixtures can either underestimate or overestimate the bending modulus of the laminate...
Article
Full-text available
The use of composite laminates for advanced structural applications has increased recently, due in part to their ability for tailoring material properties to meet specific requirements. In this regard, variable stiffness (VS) designs have potential for improved performance over constant stiffness designs, made possible by fibre placement technologi...
Article
Cut-outs are widely used to accommodate windows, openings for access purposes or fasteners in primary structural parts of airplanes. The presence of cut-outs in composite panels results in stress or strain concentrations leading to potentially reduced load carrying capacity. Steering tows around cut-outs using emerging techniques in 3D printing and...
Article
Full-text available
The Unified Formulation (UF) has gained attention as a powerful tool for efficient design of structural components. Due to the inherent flexibility of its kinematics representation, arbitrary shape functions can be selected in different dimensions to achieve a high-fidelity characterisation of structural response under load. Despite this merit, the...
Article
Full-text available
Non-prismatic beams are widely employed in several engineering fields, e.g., wind turbines, rotor blades, aircraft wings, and arched bridges. While analytical solutions for variable cross-section beams are desirable, a model describing all stress components for beams with general variation of their cross-section under generalised loading remains an...
Article
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Engineering systems are typically governed by systems of high-order differential equations which require efficient numerical methods to provide reliable solutions, subject to imposed constraints. The conventional approach by direct approximation of system variables can potentially incur considerable error due to high sensitivity of high-order numer...
Article
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Composite materials can enhance morphing and deployable structure capability due to their high degree of tailorability and their favourable stiffness- and strength-to-weight ratios. One such structure, the bistable helical lattice, is augmented in current work. To date this type of structure, shows promise in aerospace systems which require linear...
Article
Full-text available
The introduction of the variable stiffness concept has broadened the design space for high-performance lightweight composite structures. In particular, when considering prestressed dynamically excited aerospace components, a wider design space allows designers to find more effective solutions with higher overall stiffness and fundamental frequency....
Article
Flexible hinges enable the design of folding structures without using mechanisms by making use of intrinsic structural characteristics in the action of folding. This technology introduces potential benefits including weight reduction, omission of lubrication and potentially better system reliability. To achieve such technology, we exploit a well-kn...
Article
Full-text available
Beams resting on elastic foundations are widely used in engineering design such as railroad tracks, pipelines, bridge decks, and automobile frames. Laminated composite beams can be tailored for specific design requirements and offer a desirable design framework for beams resting on elastic foundations. Therefore, the analysis of flexural behaviour...
Article
Full-text available
Deployable spacecraft technology should be both lightweight and compact for storage while also being rigid and expansive once deployed. A new type of structure that can meet both of these requirements is the morphing cylindrical lattice. This multi-stable structure can morph from a compact stowed state, to a long and slender deployed beam. It compr...
Article
Full-text available
The fully anisotropic response of composite beams is an important consideration in diverse applications including aeroelastic responses of helicopter rotor and wind turbine blades. Our goal is to present exact analytical solutions for the first time for coupled deflection of Euler-Bernoulli composite beams. Towards this goal, two approaches are pro...
Article
Full-text available
An analytical solution is obtained for the 3D static deflection of variable stiffness composite beams subject to non-uniformly distributed loads. Governing differential equations with variable coefficients, reflecting the spatially variable stiffness properties, are presented in which four degrees of freedom are fully coupled. The general analytica...
Conference Paper
Full-text available
In this work, the bending stiffness of a fibre composite lamina is investigated analytically by using Euler­ Bernoulli elasticity theory. Closed form solutions are obtained for the equivalent bending modulus, E ̂_b, in terms of fibre volume fraction, v_f, mismatch of fibre-matrix material properties, β=E_f/E_m and the number of fibres, N, in the th...
Conference Paper
Design of primary structural parts for aerospace applications is a challenging process. When it comes to multi-part units such as a wingbox, it becomes even more demanding due to added complexity arising from assembly and integration processes, together with their associated considerations and limitations. In this work, a three-meter long, variable...
Conference Paper
Composite cylindrical shells are widely used in space launch systems due to their high load-carrying capability and also for being light weight. However, these structures are prone to buckle at a much lower load than classical predictions for the perfect cylinder. In literature, the effect of geometrical imperfections on the buckling response of th...
Conference Paper
Geometric imperfection sensitivity is the largest influencing factor that limits the design of thin-walled monocoque cylinders. Current generation cylindrical architectures, such as those found in rocket launch vehicles, rely on the use of sandwich or blade-stiffened structures to reduce the imperfection sensitivity of the cylinder. Whilst much res...
Conference Paper
Full-text available
Geometrically nonlinear analysis is an important procedure for accurate stress prediction of flexible beam structures that undergo large displacements and rotations. In the context of geometrically nonlinear analysis, the Unified Formulation (UF) has shown capability for efficient prediction of stresses in thin and thick composite beams using high-...
Conference Paper
The design of localized and controlled compliance in thin-walled structures by exploiting unstable behavior during bending, i.e. Brazier phenomena, has potential for dispensing with mechanically-hinged structures. This morphing hinge-free technology offered by flexible hinges saves weight, eliminates friction-related problems and reduces part-count...
Conference Paper
Cut-outs are widely used to accommodate windows, openings for access purposes or fasteners in primary structural parts of airplanes. The presence of cut-outs in composite panels results in stress or strain concentrations and potentially reduced load carrying capacity. A promising solution to alleviate the stress concentration is to tailor the panel...
Conference Paper
Full-text available
The exact analytical solutions for static response of fully coupled composite beams subject to arbitrary loading and boundary conditions are presented. The analysis is based on the Euler-Bernoulli and Timoshenko beam theories. The governing equations are presented as a set of coupled inhomogeneous ordinary differential equations, and then expressed...
Conference Paper
Full-text available
Modelling of laminated structures requires adequate computational frameworks which can accurately estimate displacement and stress fields resulting from systems of high-order partial differential equations [1]. The recently developed inverse differential quadrature method (iDQM) [2] shows promising outcomes for obtaining solution of high-order syst...
Article
The mechanical properties, thermal behaviour, and spectral characteristics of polydimethylsiloxane (PDMS) composites utilising a nonwoven polyetherimide (PEI) veil with SrAl2O4:Eu²⁺, Dy³⁺ (SAOED) phosphors have been investigated. Elasto-mechanoluminescence (EML) was characterised by observing the light emission under cyclic displacement testing. EM...
Article
The design of thin-walled cylinders in axial compression is limited by sensitivity to geometric imperfections. This paper focuses on reducing this imperfection sensitivity from a design perspective. By using variable-angle composites, the load paths are tailored to reduce the effective area over which imperfections can initiate buckling. Continuous...
Article
Full-text available
Composite materials, due to their high specific strength and stiffness, are commonly used to design lightweight structures. However, the anisotropy of composite laminates induces complex multi-modal failure mechanisms and often undesired mechanical couplings. For this reason, empirically-based design guidelines are generally employed to increase co...
Article
Full-text available
Increasing applications of laminated composite structures necessitate the development of equivalent single layer (ESL) models that can achieve similar accuracy but are more computationally efficient than 3D or layer-wise models. Most ESL displacement-based models do not guarantee interfacial continuity of shear stresses within laminates. A possible...
Article
Full-text available
A parametrically driven structural model based on Mindlin-Reissner plate theory is developed to capture the three-dimensional deflections of a compliance-based morphing trailing edge device with severe structural discontinuities. The model is used to study the Fish Bone Active Camber (FishBAC) device, which is represented as a discontinuous plate s...
Article
The optimal design of the postbuckling response of variable angle tow composite structures is an important consideration for future lightweight, high-performing structures. Based on this premise, a new optimisation tool is presented for shell-type structures. The starting point is an isogeometric framework which uses NURBS interpolation functions t...
Article
Full-text available
Pressure vessels enable liquids and gases to be stored and transported safely, finding pervasive use in many industries. These types of structure can be manufactured into many different shapes and from various materials to satisfy the requirements of their specific applications. Maximum allowable pressure is an important factor that should be consi...
Article
Full-text available
Due to high specific strength and stiffness ratios, composite materials are widely used in industries where minimising structural mass is of paramount importance, such as the aerospace sector. However, designing lightweight composite laminates is challenging due to the large number of discrete design variables involved, e.g. ply numbers and fibre o...
Article
Full-text available
Structures used in space applications demand the highest levels of stiffness for their mass whilst also performing in a hostile environment. To partly address these requirements and so as to also pack efficiently for stowage during launch we propose a new type of compact telescopic morphing lattice space boom. This boom stows within a 1U CubeSat vo...
Article
Full-text available
Aerospace and industries where both localised compliance and weight savings play a central role in design can benefit from using flexible hinges. These morphing structures use no mechanical hinges for folding. They fold by exploiting the limit point, i.e. the Brazier moment, of a geometrically nonlinear structural response characteristic of thin-wa...
Article
Full-text available
Using the Variational Iteration Method (VIM) the 3D static deflection problem of composite beams subject to concentrated tip and uniformly distributed loads is analysed, resulting in a system of coupled non-homogeneous ordinary differential equations. Using a general Lagrange multiplier, identified by variational theory, a special type of functiona...
Conference Paper
Full-text available
As materials and engineering design tools become more complex, engineers are looking to mimic structures and systems, occurring in nature, to design more efficient mechanical structures. One such structure is a morphing composite lattice structure, whose design was inspired by the tail of the bacteriophage T4 virus [1]. To date the morphing behavio...
Chapter
The buckling behavior of bamboo culm is highly affected by internodal properties, i.e. material properties and geometric parameters of the trunk. In this study, the effects of Phyllostachys Edulis bamboo culms have on buckling phenomena under bending and compressive loads are investigated. Internodal walls are assumed to be composed of orthotropic...
Article
Full-text available
Elastic boundary conditions play an important role in the buckling analysis of cylinders under compressive loading. These structures are used widely in aerospace applications and are highly sensitive to geometrical, material, loading, and boundary imperfections. In fact, the presence of these imperfections can lead to catastrophic failure. In 1968,...
Conference Paper
Full-text available
The development of software and methodologies able to efficiently and accurately predict the aeroelastic performance of wind turbines at low computational cost — enabling the rapid turnaround of novel concepts — is key to further reducing the levelised cost of energy. However, even the conventional low fidelity methods used for preliminary blade an...
Article
Full-text available
This paper presents, through the structural design of a 20 MW wind turbine blade, a selection of novel analysis and optimisation methods for wind turbines. These methods are integrated in the software— A eroelastic T urbine O ptimisation M ethods (ATOM). A key feature is the novel, computationally-efficient piecewise linear model for running rapid...