Paul M. Weaver

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

PhD

About

497
Publications
210,893
Reads
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14,479
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
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
January 1998 - present
University of Bristol
Position
  • Professor in Lightweight Structures

Publications

Publications (497)
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
Pressure vessels are widely used in various aerospace and automotive applications. For some applications with limited space, spherical and ellipsoidal shapes are less attractive than toroids. Toroidal shapes can be defined as curved, endless hollow shapes that eliminate the need for end caps when used for pressure vessels. This study presents an an...
Article
Full-text available
This dataset encapsulates comprehensive information and experimental outcomes derived from the buckling test of variable-stiffness composite cylinders subjected to axial compression. It is the first dataset about the correlation between experimental and computational analysis for a Rapid-Tow Sheared composite cylinder, a recently developed advanced...
Article
Full-text available
Wind turbine blades are complex structures and, despite advancements in analysis techniques, differences persist between predictions of their elastic response and experimental results. This undermines confidence in the ability to reliably design and certify novel blade designs that include self-regulating features like bend–twist coupling. To addre...
Conference Paper
Incorporating, by design, tensile buckling into the macroscopic response of lattice structures offers a novel approach for adaptive (meta-)material/structure development. In this study, we explore the potential of utilizing the simultaneous tensile buckling of adjacent cells to induce a transformation in lattice topology. Unit cells are passively t...
Preprint
Full-text available
Wind-turbine blades are complex structures and, despite advancements in analysis techniques, differences persist between predictions of their elastic response and experimental results. This undermines confidence in the ability to reliably design and certify novel blade designs that include self-regulating features like bend-twist coupling To addres...
Article
Since the introduction of variable-stiffness composites, the design philosophy for high-performance lightweight composite structures has broadened greatly. Indeed, variable-stiffness composites have been shown to increase buckling performance and dynamic stability, as well as to modify the dynamic response by tailoring stiffness distributions. Thus...
Presentation
Full-text available
Invited lecture at Jiangsu University of Technology
Article
Full-text available
The capabilities of the rapid tow shearing (RTS) process are explored to reduce the well-known imperfection sensitivity of axially compressed cylindrical shells. RTS deposits curvilinear carbon fibre tapes with a fibre-angle-thickness coupling that enables the in situ manufacturing of embedded rings and stringers. By blending the material’s elastic...
Article
Structures with adaptive stiffness characteristics present an opportunity to meet competing design requirements, thus achieving greater efficiency by the reconfiguration of their topology. Here, the potential of using changes in the topology of planar lattice structures is explored to achieve this desired adaptivity and observe that lattice structu...
Article
The present work studies the thermal degradation of laser-heated poly-ether-ether-ketone (PEEK) as the heating duration increases. Its damage morphology, chemical composition, crystallinity content, and mechanical properties are examined with optical microscopy, attenuated total reflection-Fourier transform infrared spectroscopy, differential scann...
Conference Paper
Full-text available
Analysis of wind turbine blades using beam or shell models presents difficulties in accurately capturing the torsional stiffness and local 3D stress fields. Instead, modeling torsional effects accurately often necessitates three-dimensional analysis as achieved with solid elements in finite element analysis. The use of solid elements and complex lo...
Conference Paper
Large deflection analysis is an essential requirement to characterize the behavior of flexible beam structures including wings and rotor blades that undergo large displacements during service. The introduction of composite materials and particularly variable angle tow (VAT) technology make it possible to meet the lightweight and high-strength requi...
Article
Variable-angle tow (VAT) manufacturing methods significantly increase the design space for elastic tailoring of composite structures by smoothly changing fiber angle and ply thickness across a component. Rapid tow shearing (RTS) is a VAT manufacturing technique that uses in-plane shearing (rather than in-plane bending) to steer tows of dry or pre-i...
Conference Paper
Full-text available
Free vibration analysis is an essential requirement to capture the behaviour of composite structures subject to dynamic loading environment. To enhance the vibratory behaviour of composite structures, variable stiffness (VS) concept offers increased design flexibilities to tailor the structural response to meet a wide range of applications. Mechani...
Article
A micromechanical model for the analysis of structurally periodic flexoelectric plates with periodically varying thickness is developed on the basis of asymptotic homogenization. The period of thickness variation is small and comparable to the plate thickness; accordingly, the plate is usually referred to as having a “rapidly varying thickness.” Th...
Article
An essential aspect of design of laminated plate structures in many engineering applications is the analysis of free vibration behaviour in order to model the structure for random excitations. In this regard, numerical solutions to the systems of high-order partial differential equations governing free vibration response of the structure become imp...
Article
Over the past 25 years, interest in thermoplastic composites in aircraft has steadily increased. Combining winding and laser-assisted tape placement is a promising method to manufacture thermoplastic structures using in-situ consolidation, as shown recently by manufacturing a variable stiffness, unitized, integrated-stiffener thermoplastic wingbox...
Article
The design of composite flexible hinges in folding structures by exploiting unstable behaviour during bending, i.e. Brazier phenomena, can preclude the added weight and complexity of mechanical hinges. Novel applications motivating this study include folding aircraft wingtips to increase wing aspect-ratio and to comply with airport space restrictio...
Article
Full-text available
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
Full-text available
Pressure vessels are widely used in a broad range of applications in many industries including possible use for hydrogen storage. Additionally, pressure vessels comprise non-circular section fuselages such as in blended wing body aircraft. Failure performance, weight and packing efficiency are important factors that should be considered when design...
Article
Full-text available
A key aspect in the design of deployable space structures comprising slender elements such as booms is their deployed bending stiffness. In space, due to zero gravitational loading, a high level of bending stiffness is not required to support neighbouring structures, but instead is desirable to resist vibrations generated by the attitude control sy...
Article
In recent decades, renewable energy has attracted attention as a viable energy supply. Among renewable energy sources, offshore wind energy has been considerably growing since longer and larger wind turbine composite blades were deployed. The manufacture of the longer and larger composite blades leads to more wind energy production. However, the wi...
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
Full-text available
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...
Conference Paper
Planar cellular lattice structures subject to axial compression may undergo elastic bending or buckling of the unit cells. If sufficient compression is applied, the columns of adjacent cells make contact. This changes the topology of the lattice by establishing new load paths. This topology change induces a corresponding shift in the effective stif...
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
Full-text available
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
Full-text available
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
Full-text available
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...