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Journal articleDalchau N, Szep G, Hernansaiz-Ballesteros R, et al., 2018,
Computing with biological switches and clocks
, NATURAL COMPUTING, Vol: 17, Pages: 761-779, ISSN: 1567-7818- Cite
- Citations: 33
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Journal articleLakin MR, Phillips A, 2018,
Automated analysis of tethered DNA nanostructures using constraint solving
, NATURAL COMPUTING, Vol: 17, Pages: 709-722, ISSN: 1567-7818- Cite
- Citations: 4
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Journal articleVillette CC, Phillips ATM, 2018,
Rate and age-dependent damage elasticity formulation for efficient hip fracture simulations
, Medical Engineering and Physics, Vol: 61, Pages: 1-12, ISSN: 1350-4533Prediction of bone failure is beneficial in a range of clinical situations from screening of osteoporotic patients with high fracture risk to assessment of protective equipment against trauma. Computational efficiency is an important feature to consider when developing failure models for iterative applications, such as patient-specific diagnosis or design of orthopaedic devices. The authors previously developed a methodology to generate efficient mesoscale structural full bone models. The aim of this study was to implement a damage elasticity formulation representative of an elasto-plastic material model with age and strain rate dependencies compatible with these structural models. This material model was assessed in the prediction of femoral fractures in longitudinal compression and side fall scenarios. The simulations predicted failure loads and fracture patterns in good agreement with reported results from experimental studies. The observed influence of strain rate on failure load was consistent with literature. The superiority of a simplified elasto-plastic formulation over an elasto-brittle bone material model was assessed. This computationally efficient damage elasticity formulation was capable of capturing fracture development after onset.
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Journal articleBai L, Yang J, Wadee MA, 2018,
Cellular buckling from nonlinear mode interaction in unequal-leg angle struts
, Thin-Walled Structures, Vol: 132, Pages: 316-331, ISSN: 0263-8231A variational model based on total potential energy principles that describes the nonlinear mode interaction in thin-walled unequal-leg angle struts under pure axial compression is presented. The formulation, which combines continuous displacement functions and generalized coordinates, leads to the derivation of a system of differential and integral equations that describe the static equilibrium response of the strut. Solving the system of equations using numerical continuation techniques reveals, for the first time, progressive cellular buckling (or snaking) represented by a sequence of snap-back instabilities arising from the nonlinear interaction of the weak-axis flexural, strong-axis flexural and torsional buckling modes—the resulting behaviour being highly unstable. For verification purposes, a finite element (FE) model is also devised and the sequential snap-back instabilities are also captured within its framework. Moreover, once an initial geometric perturbation is incorporated within the variational model it compares very well with the FE model.
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Journal articleZaharie DZ, Phillips ATM, 2018,
Pelvic construct prediction of trabecular and cortical bone structural architecture
, Journal of Biomechanical Engineering, Vol: 140, Pages: 1-11, ISSN: 0148-0731The pelvic construct is an important part of the body as it facilitates the transfer of upper body weight to the lower limbs and protects a number of organs and vessels in the lower abdomen. In addition, the importance of the pelvis is highlighted by the high mortality rates associated with pelvic trauma. This study presents a mesoscale structural model of the pelvic construct and the joints and ligaments associated with it. Shell elements were used to model cortical bone, while truss elements were used to model trabecular bone and the ligaments and joints. The finite element (FE) model was subjected to an iterative optimization process based on a strain-driven bone adaptation algorithm. The bone model was adapted to a number of common daily living activities (walking, stair ascent, stair descent, sit-to-stand, and stand-to-sit) by applying onto it joint and muscle loads derived using a musculoskeletal modeling framework. The cortical thickness distribution and the trabecular architecture of the adapted model were compared qualitatively with computed tomography (CT) scans and models developed in previous studies, showing good agreement. The sensitivity of the model to changes in material properties of the ligaments and joint cartilage and changes in parameters related to the adaptation algorithm was assessed. Changes to the target strain had the largest effect on predicted total bone volumes. The model showed low sensitivity to changes in all other parameters. The minimum and maximum principal strains predicted by the structural model compared to a continuum CT-derived model in response to a common test loading scenario showed good agreement with correlation coefficients of 0.813 and 0.809, respectively. The developed structural model enables a number of applications such as fracture modeling, design, and additive manufacturing of frangible surrogates.
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Journal articleMurphy N, Petersen R, Phillips A, et al., 2018,
Synthesizing and tuning stochastic chemical reaction networks with specified behaviours
, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 15, ISSN: 1742-5689- Cite
- Citations: 9
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Journal articleBoulanger DSM, Eccleston RC, Phillips A, et al., 2018,
A Mechanistic Model for Predicting Cell Surface Presentation of Competing Peptides by MHC Class I Molecules
, FRONTIERS IN IMMUNOLOGY, Vol: 9, ISSN: 1664-3224- Cite
- Citations: 23
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Journal articleZhang JX, Fang JZ, Duan W, et al., 2018,
Predicting DNA hybridization kinetics from sequence
, NATURE CHEMISTRY, Vol: 10, Pages: 91-98, ISSN: 1755-4330- Cite
- Citations: 132
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Journal articleBai L, Wang F, Wadee MA, et al., 2017,
Nonlinear mode interaction in equal-leg angle struts susceptible to cellular buckling
, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol: 473, Pages: 1-22, ISSN: 1364-5021A variational model that describes the interactive buckling of a thin-walled equal-leg angle strut under pure axial compression is presented. A formulation combining the Rayleigh-Ritz method and continuous displacement functions is used to derive a system of differential and integral equilibrium equations for the structural component. Solving the equations using numerical continuation reveals progressive cellular buckling (or snaking) arising from the nonlinearinteraction between the weak-axis flexural buckling mode and the strong-axis flexural-torsional buckling mode for the first time - the resulting behaviour being highly unstable. Physical experiments conducted on 10 cold-formed steel specimens are presented andthe results show good agreement with the variational model.
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Journal articleLapira L, Wadee MA, Gardner L, 2017,
Stability of multiple-crossarm prestressed stayed columns with additional stay systems
, Structures, Vol: 12, Pages: 227-241, ISSN: 2352-0124Prestressed stayed columns have an enhanced resistance to buckling through the effective use of crossarms and pretensioned stays when compared to conventional columns. An analytical derivation of the minimum, linear optimum and maximum initial pretension forces for configurations of prestressed stayed columns with multiple crossarms and additional stays is presented for the first time. The findings are validated through comparisons with finite element models developed in the commercial package ABAQUS. The influence of the initial pretension on the load-carrying capacity of the configurations considered is also analysed, providing insight into the actual optimum initial pretension force for the configurations accounting for the significance of geometric nonlinearities.
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