Zhenmin Zou

The University of Manchester · School of Mechanical, Aerospace and Civil Engineering

This study investigates the effect of interface hybrid toughening on the fatigue performance of composite laminates by examining a single-step joint configuration with a bondline incorporating core-shell rubber (CSR) nanoparticles and thermoplastic micro-fiber polyphenylene sulfide (PPS) veils. Three types of bondlines for the single-step joint con...

This paper investigates how combining natural and synthetic fibers within yarns, altering the degree of hybridisation, and varying weave architectures affect the homogenized elastic properties and stress distributions in 2D woven composite laminae using a two‐scale homogenization scheme. The novelty lies in integrating a micro‐scale representative...

This research investigates the static and high-cycle-fatigue behaviour and failure mechanisms of co-cured composite single-step joints with two-scale interface toughening. Resin infusion followed by out-of-autoclave curing is used to manufacture the co-cured carbon/epoxy composite single-step joints without a structural adhesive. The co-cured compo...

Traditional thermosetting composites have high specific strength and stiffness but exhibit poor damage tolerance. To address this, fibre hybridisation emerges as a cost-effective strategy. This study investigates the transverse shear failure of fibre-hybrid unidirectional composite laminae, specifically primary E-glass fibres with secondary fibres...

In this paper, the effect of intra-yarn fibre hybridisation on the homogenised elastic properties and micro- and meso-scale matrix stress fields in 2D woven composite laminae (i.e. plain, 2/2 basket, 2/2 twill and 5-harness satin) is studied with a two-scale homogenisation scheme—employing a representative volume element model at micro-scale and a...

This paper investigates the effect of intra-laminar fibre hybridisation, i.e., primary and secondary fibres within a matrix, on the homogenised properties and micro-stress fields in uni-directional polymer composite laminae. The study is focused on S-glass/epoxy laminae which are hybridised with secondary fibres (e.g., polypropylene). Two-dimension...

In this work, unidirectional composite laminae with intra-laminar fibre hybridisation (i.e. two fibre types within a matrix) are studied to understand the influence of solid and hollow glass fibre content on the homogenised specific lamina properties of and the matrix micro-stress fields in carbon/solid-E-glass/epoxy and carbon/hollow-E-glass/epoxy...

This study investigates the effect of fiber‐hybrid non‐woven veils on the interlaminar fracture of out‐of‐autoclave carbon/epoxy laminates. The Mode‐I and Mode‐II interlaminar toughening performance and R‐curves behavior of out‐of‐autoclave composite laminates with carbon and thermoplastic fiber‐hybrid veils are investigated. Pure carbon veil (i.e....

This study investigates the effect of intra-laminar fibre hybridisation on the homogenised lamina properties and micro-stress fields, with an emphasis on natural and synthetic fibre combinations. A representative volume element (RVE) approach, considering random fibre distributions, is employed to study unidirectional flax/E-glass/epoxy composite l...

Degenerative disc disease (DDD) has become a significant public health issue worldwide. This can result in loss of spinal function affecting patient health and quality of life. Artificial total disc replacement (A‐TDR) is an effective approach for treating symptomatic DDD that compensates for lost functionality and helps patients perform daily acti...

Human finger joints are conventionally simplified as rigid joints in robotic hand design and biomechanical hand modelling, due to their anatomic and morphologic complexity. However, our understanding of the effect of the finger joint configuration on the resulting hand performance is still primitive. In this study, we systematically investigate the...

Core-shell rubber (CSR) particles and thermoplastic polyphenylene sulphide (PPS) veils are used to achieve hybrid interlaminar toughening of carbon/epoxy laminates by using vacuum assisted resin infusion and out-of-autoclave curing. Double cantilever beam (DCB) tests are carried out to investigate the effect of hydrothermal conditioning on the mode...

The effect of short micro-fibre-based veils on the mode-I and mode-II interlaminar fracture energies and R-curves of composite laminates is investigated in this study—with an emphasis on the role of veil binders. Non-woven polyphenylene sulfide veils with 10 g/m² areal weight and two different binders (i.e. cross-linked styrene and cross-linked pol...

Conventional thermosetting composites laminates have high specific in-plane properties but low damage tolerance. An approach to enhance damage tolerance in composite laminates is to use towlevel fibre hybridization with thermoplastic fibres. This paper aims to investigate post-cure thermally-induced residual micro-stress fields within the matrix an...

This paper investigates the effect of non-hybrid and hybrid toughening, via core-shell rubber (CSR) nanoparticles and non-woven micro-fibre veils, on the delamination resistance and crack migration in carbon fibre/epoxy laminates under mode-I and mode-II conditions—with an emphasis on the effect of veil fibre properties on toughening mechanisms and...

First order cutaneous neurons allow object recognition, texture discrimination, and sensorimotor feedback. Their function is well-investigated under passive stimulation while their role during active touch or sensorimotor control is understudied. To understand how human perception and sensorimotor controlling strategy depend on cutaneous neural sig...

Quantifying the effect of routing and topology of the inter-connected finger extensor mechanism on hand grasping performances is a long-standing research problem for the better clinical diagnosis, surgical planning and biomimetic hand development. However, it is technically demanding to measure the hand performance parameters such as the contact fo...

Human shoulder joints exhibit stable but highly active characteristics due to a large amount of soft tissues. Finite Element (FE) modelling plays an important role in enhancing our understanding of the mechanism of shoulder disorders. However, the previous FE shoulder models largely neglected the Three-Dimensional (3D) volume of soft tissues and th...

This paper aims to develop and validate a subject-specific framework for modelling the human hand. This was achieved by combining medical image-based finite element modelling, individualized muscle force and kinematic measurements. Firstly, a subject-specific human hand finite element (FE) model was developed. The geometries of the phalanges, carpa...

Stabilisation of proximal humerus fractures remains a surgical challenge. Spatial subchondral support (S3) plate promises to overcome common complications associated with conventional proximal humerus plates. This study compared the biomechanical performance of S3 plate with a fixed-angle hybrid blade (Equinoxe Fx) plate and a conventional fixed-an...

The objective of this study is to quantitatively evaluate the effects of rotator cuff tear propagation on glenohumeral joint stability in a previously constructed and validated finite element shoulder model. Rotator cuff tears with a sequence of increasing sizes were created from the anterior portion of the supraspinatus osseous insertion site and...

Optimal treatment of proximal humerus fractures remains controversial. Locking plates offer theoretical advantages but are associated with complications in the clinic. This study aimed to perform parametric design optimisation of proximal humerus plates to enhance their mechanical performance. A finite element (FE) model was developed that simulate...

This paper is concerned with the development and application of a frequency-dependent cohesive-zone model (CZM) for crack-growth analysis of low and high-cycle fatigue. The new model makes use of recent advances by combining a modified version of a recently developed frequency-dependent trapezoidal cohesive-zone model (Salih et al., 2017) and a new...

A cohesive zone model has been developed for the simulation of both high and low cycle fatigue crack growth. The developed model provides an alternative approach that reflects the computational efficiency of the well‐established envelop‐load damage model yet can deliver the accuracy of the equally well‐established loading‐unloading hysteresis damag...

Background: Treatment of proximal humerus fractures with locking plates is associated with complications. We aimed to compare the biomechanical effects of removing screws and blade of a fixed angle locking plate and hybrid blade plate, on a two-part fracture model. Methods: Forty-five synthetic humeri were divided into nine groups where four wer...

Cohesive zone models coupling interface damage and friction have been developed in the literature and are available in the commercial finite element package ABAQUS to consider the enhancing effect of through-thickness compression on interfacial fracture resistance. It is revealed in this paper that these models are extremely dependent on interface...

Background Open reduction and internal fixation of proximal humerus fractures can be difficult to achieve adequate, complication free results due to osteopenia of the proximal humerus and unstable fracture patterns. This study aimed to compare the biomechanical properties of a novel hybrid fixed angle blade plate (Fx plate) with an established fixe...

Purpose An analytical investigation has been carried out for a simply supported rectangular plate with two different loading conditions by using 3D SSA. Also, the accurate location of the neutral plane through the thickness of the plate can be identified: the neutral plane is shifted away from the middle plane according to the loading condition....

This paper is concerned with a new cohesive zone model (CZM) to better describe the effects of rate and cyclic loading. Rate is known to affect the manner in which cracks propagate in materials, yet there presently exists no rate-dependent cohesive model for fatigue simulation. The frequency of the applied cyclic load is recognised to influence cra...

Experiments in the literature show that through-thickness compressive stress significantly enhances interfacial fracture resistance. Most existing cohesive zone and interface element models which consider the enhancement only introduce friction in the model. In this paper, a new method is proposed to include both friction and enhanced interfacial s...

Fractures of proximal humerus are currently the third most common fractures in patients over the age of 65 years. An integrated experimental and computational framework is proposed for the development of novel proximal humerus plates with enhanced biomechanical and clinical performance. It involves in vitro mechanical testing of leading proximal hu...

To overcome deficiencies with existing approaches a new cohesive zone model is introduced and trialled in this paper. The focus is on rate-dependent cohesive zone models which have appeared in the recent literature but can be shown to suffer unrealistic behaviour. Different combinations of material response are examined with rate effects appearing...

In this paper, state space approach (SSA) is used for the determination of structural behaviour of simply supported orthotropic composite plates under uniformly transverse loading. The response results obtained by using SSA are then compared with the numerical results from finite element method (FEM). The effect of element types and mesh sizes on d...

The human shoulder is a complicated musculoskeletal structure and is a perfect compromise between mobility and stability. The objective of this paper is to provide a thorough review of previous finite element (FE) studies in biomechanics of the human shoulder complex. Those FE studies to investigate shoulder biomechanics have been reviewed accordin...

In this paper, state space approach (SSA) and finite element method (FEM) are used for simply supported orthotropic composite plates under different types of loading. The results obtained by using SSA are compared with the numerical results from ABAQUS. The effect of the plate thickness on displacements and stresses is described quantitatively. The...

Periacetabular osteotomy (PAO) is a surgical procedure to correct acetabular orientation in developmental dysplasia of the hip (DDH). It changes the position of the acetabulum to increase femoral head coverage and distribute the contact pressure over the cartilage surface. The success of PAO depends significantly on the surgeon's experience. Using...

Central reflection as a type of symmetry has been exploited in the context of structural analysis for the first time in this paper, especially in terms of applications to the formulation of unit cells for micromechanical FE analysis of materials of periodic microstructures. It reduces the size of the unit cell to be analysed without compromising us...

The periodic conditions of a microstructure with a staggered pattern have been systematically examined. A general unit cell has been formulated to which either any single component or any combination of the macroscopic stresses can be applied in the form of a load under a unique set of boundary conditions. The formulated unit cell and the obtained...

The aim of this paper is to validate the use of a finite-element (FE) based continuum damage mechanics (CDM) failure model to simulate the debonding and fracture of restored teeth. Fracture testing of plastic model teeth, with or without a standard Class-II MOD (mesial-occusal-distal) restoration, was carried out to investigate their fracture behav...

The in-plane dynamic crushing of 2D hexagonal-cell honeycombs has been simulated using finite elements to explore the dynamic response of cellular materials and to investigate the features of the crushing front and to examine the assumptions employed in a one-dimensional shock theory [Reid SR, Peng C. Dynamic uniaxial crushing of wood. Int J Impact...

The aim of this paper was to assess the suitability of the sandwiched beam in three-point bending as a technique for determining fracture toughness and R-curve behaviour of nuclear graphite using small beam specimens. Surface displacements of the cracked beam specimen were measured using Electronic Speckle Pattern Interferometry (ESPI) and Image Co...

The development of an analytical model based on a ‘bar–hinge’ idealisation is described. It is used to investigate the structural response of a one-dimensional chain of components each constructed from a pair of slightly bent elastic–plastic struts under axial impact loading. Each component (a typical type II structure) in the chain is modelled as...

This paper presents the latest development by the authors in modelling damage due to low velocity impact, i.e., negligible role of inertia to laminated composites. The most common modes of damage are transverse cracking and delamination. The problem has been addressed in a series of publications by the authors. Upon a successful partition of the to...

One-dimensional ‘steady-shock’ models based on a rate-independent, rigid, perfectly-plastic, locking (r-p-p-l) idealisation of the quasi-static stress–strain curves for aluminium foams are proposed for two different impact scenarios to provide a first-order understanding of the dynamic compaction process. A thermo-mechanical approach is used in the...

Experimental tests on graphite moderator bricks with keyways have been simulated using a failure model recently developed by the authors based on continuum damage mechanics. Failure of the specimens, induced by the application of pure bending moment, is characterised by unstable crack propagation, with very small cracks and damage zones formed at t...

This study of the dynamic compressive strength properties of metal foams is in two parts. Part I presents data from an extensive experimental study of closed-cell Hydro/Cymat aluminium foam, which elucidates a number of key issues and phenomena. Part II focuses on modelling issues. The dynamic compressive response of the foam was investigated using...

This paper is motivated by the somewhat unusual need to gain insight into the phenomenology of the mechanism by which a wavy edge is formed on the wreckage of some aircraft fuselage skins associated with aircraft destroyed in flight by on-board explosion.In order to explore the role of the plastic zone adjacent to the crack tip whilst avoiding the...

A failure model for nuclear graphite is presented in the context of continuum damage mechanics. It relates tractions to the relative displacements at an interface where cracking may occur. Both the stress-based and fracture-mechanics-based failure criteria are included in the model to construct a damage surface which shrinks in the stress space as...

Delamination, a typical mode of interfacial damage in laminated composites, has been considered in the context of continuum damage mechanics in this paper. Interfaces where delaminations could occur are introduced between the constituent layers. A simple but appropriate continuum damage representation is proposed. A single scalar damage parameter i...

A model for progressive interlaminar delamination is presented for laminated composite structures. Instead of a cumbersome 3D description, a computationally efficient 2D technique is adopted which models the laminated structure as an assembly of sublaminates connected through their interfaces. Constraints between sublaminates are removed to represe...

When two–dimensional or three–dimensional elasticity theory is applied to interfacial cracks, individual components of th energy–release rate are not well defined in their classical crack closure integral form due to oscillatory stress and displacemen fields around crack tips. These are associated with physically inadmissible interpenetration of cr...

Stresses around two similar circular cylindrical inclusions in an infinite medium under the generalised plane strain conditions subjected to uniform far-field stresses are investigated in this paper. The analysis is based on the complex stress potentials of Muskhelishvili [1]. Stresses can be found with any clearance between the two inclusions. Spe...

A pragmatic modelis proposed to predict interlaminar and intralaminar damage, i.e., delamination and matrix cracking, in filament wound pipes. The pipe is modelled as an assembly of sublaminates connected along their interfaces. The initiation of delamination and transverse matrix cracking is predicted based on stress-based failure criterion. Delam...

Individual energy release rates for delamination in composite laminates do not exist according to two- or three-dimensional elastic theory due to the oscillatory characteristics of the stress and displacement fields near the delamination tip (Sun, C.T., Jih, C.J., 1987. Engng. Fracture Mech. 28, 13–20; Raju, I.S., Creus Jr., J.H., Aminpour, M.A., 1...

An experimental procedure is described for measuring the critical energy release rate GIIC of filament wound pipes by making use of lateral indentation experiments on these pipes and correlating the dissipated energy to the delamination area. Factors that might influence the results of this procedure are discussed. Two pipes of different nominal th...

The effective properties of composites can be predicted from those of their constituents by analysing some appropriate unit cells. Such an analysis can be used in an opposite way to back out some properties of one of the constituents, in particular, the transverse properties of the fibre, from the effective properties of the composite, given the pr...