Imperial College London
Emeritus Professor Gordon Williams

Emeritus Professor Gordon Williams

Faculty of Engineering, Department of Mechanical Engineering

Academic Visitor
 
 
 
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Contact

 

+44 (0)20 7594 7200g.williams Website

 
 
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Location

 

343City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

302 results found

Williams JG, 2010, Particle toughening of polymers by plastic void growth, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 70, Pages: 885-891, ISSN: 0266-3538

Journal article

Williams JG, Patel Y, Blackman BRK, 2010, A fracture mechanics analysis of cutting and machining, ENGINEERING FRACTURE MECHANICS, Vol: 77, Pages: 293-308, ISSN: 0013-7944

Journal article

Gamonpilas C, Charalambides MN, Williams JG, Dooling PJ, Gibbon SRet al., 2010, PREDICTING THE MECHANICAL BEHAVIOUR OF STARCH GELS THROUGH INVERSE ANALYSIS OF INDENTATION DATA, APPLIED RHEOLOGY, Vol: 20, ISSN: 1430-6395

Journal article

Patel Y, Blackman BRK, Williams JG, 2009, Measuring fracture toughness from machining tests, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, Vol: 223, Pages: 2861-2869, ISSN: 0954-4062

Journal article

Patel Y, Blackman BRK, Williams JG, 2009, Determining fracture toughness from cutting tests on polymers, ENGINEERING FRACTURE MECHANICS, Vol: 76, Pages: 2711-2730, ISSN: 0013-7944

Journal article

Gamonpilas C, Charalambides MN, Williams JG, 2009, Determination of large deformation and fracture behaviour of starch gels from conventional and wire cutting experiments, JOURNAL OF MATERIALS SCIENCE, Vol: 44, Pages: 4976-4986, ISSN: 0022-2461

Journal article

Stapountzi OA, Charalambides MN, Williams JG, 2009, Micromechanical models for stiffness prediction of alumina trihydrate (ATH) reinforced poly (methyl methacrylate) (PMMA): Effect of filler volume fraction and temperature, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 69, Pages: 2015-2023, ISSN: 0266-3538

Journal article

Blackman BRK, Kinloch AJ, Sanchez FSR, Teo WS, Williams JGet al., 2009, The fracture behaviour of structural adhesives under high rates of testing, Engineering Fracture Mechanics, Vol: 76, Pages: 2868-2889, ISSN: 0013-7944

Structural adhesive joints were subjected to high loading rates in mode I and their resulting fracture behaviour was studied in detail. Joints were formed between unidirectional carbon-fibre epoxy composites and between aluminium alloy substrates bonded with a tough, single-part automotive adhesive (XD4600) from Dow Automotive. Double cantilever beam (DCB) and tapered double cantilever beam (TDCB) tests were performed, from quasi-static loading rates up to 15 m/s, and a test rig was developed incorporating high-speed video acquisition for the high-speed tests. A detailed data reduction strategy was developed to account for (i) the types of different fracture behaviour regimes encountered, (ii) the dynamic effects in the test data, and (iii) the contribution of kinetic energy in the specimen arms to the energy balance. Using the above data reduction strategy, increasing the test rate over six decades (from 10−5 to 101 m/s) was found to lead to a reduction in the value of the adhesive fracture energy, GIc, by about 40% of its quasi-static value, i.e. from 3.5 to about 2.2 kJ/m2. Further, at quasi-static loading rates, the measured adhesive fracture energies were independent of substrate material and test geometry (i.e. DCB or TDCB). However, at faster loading rates, the TDCB tests induced higher crack velocities for a given loading rate compared with the DCB test geometry, and neither the test rate nor the crack velocity were found to be the parameter controlling the variation in GIc with increased test rate. Thus, an isothermal–adiabatic model was developed and it was demonstrated that such a model could unify the DCB and TDCB test results. Indeed, when the GIc values were plotted as a function of 1/√time, where the time was defined to be from the onset of loading the material to that required for the initiation of crack growth, the results collapsed onto a single master curve, in agreement with the isothermal–adiabatic model.

Journal article

Williams JG, Gamonpilas C, 2008, Using the simple compression test to determine Young's modulus, Poisson's ratio and the Coulomb friction coefficient, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, Vol: 45, Pages: 4448-4459, ISSN: 0020-7683

Journal article

Gamonpilas C, Charalambides MN, Williams JG, Dooling PJ, Gibbon SRet al., 2008, Characterisation of fracture behaviour of starch gels using conventional fracture mechanics and wire cutting tests, 15th International Congress on Rheology/80th Annual Meeting of the Society-of-Rheology, Publisher: AMER INST PHYSICS, Pages: 1232-+, ISSN: 0094-243X

Conference paper

Kawashita LF, Kinloch AJ, Moore DR, Williams JGet al., 2008, The influence of bond line thickness and peel arm thickness on adhesive fracture toughness of rubber toughened epoxy-aluminium alloy laminates, International Journal of Adhesion and Adhesives, Vol: 28, Pages: 199-210, ISSN: 0143-7496

The adhesive fracture toughness (G(A)) of rubber toughened epoxy-aluminium alloy laminates is studied using two types of peel test, namely fixed arm peel and roller-assisted mandrel peel. In the fixed arm tests, the peel angle is varied in the range 45-135 degrees and in the mandrel peel experiments, the mandrel roller size is selected in order to ensure conformance of the peel arm to the roller during fracture. The principal aims of the study are two-fold: (i) To investigate the influence of adhesive bond line thickness on G(A). (ii) To investigate the influence of peel arm thickness on G(A). The peel crack growth experiments were complemented with measurements of cohesive fracture toughness using tapered double cantilever beam geometry with a range of values for bond line thickness. Throughout the work, it is important to identify the mode of peel fracture and in particular to establish whether the peel cracks are cohesive (propagating in the adhesive) or interfacial (propagating at the interface between adhesive and substrate). To this effect, confocal laser scanning microscopy was used in order to study the peel arms after testing and to measure the thickness of adhesive coating on the peel arms. The experimental work was conducted on a wide range of laminates where two adhesives with a common substrate were employed. (C) 2007 Elsevier Ltd. All rights reserved.

Journal article

Gamonpilas C, Charalambides MN, Williams JG, Dooling PJ, Gibbon SRet al., 2008, Characterisation of large deformation behaviour of starch gels using compression and indentation techniques, 15th International Congress on Rheology/80th Annual Meeting of the Society-of-Rheology, Publisher: AMER INST PHYSICS, Pages: 1189-+, ISSN: 0094-243X

Conference paper

Xiao W, Charalambides MN, Williams JG, 2007, Sheeting of wheat flour dough, INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY, Vol: 42, Pages: 699-707, ISSN: 0950-5423

Journal article

Williams JG, Rink M, 2007, The standardisation of the EWF test, ENGINEERING FRACTURE MECHANICS, Vol: 74, Pages: 1009-1017, ISSN: 0013-7944

Journal article

Andena L, Rink A, Williams JG, 2006, Cohesive zone modelling of fracture in polybutene, 4th Conference on Fracture of Polymers, Composites and Adhesives, Publisher: PERGAMON-ELSEVIER SCIENCE LTD, Pages: 2476-2485, ISSN: 0013-7944

Conference paper

Cotterell B, Hbaieb K, Williams JG, Hadavinia H, Tropsa Vet al., 2006, The root rotation in double cantilever beam and peel tests, MECHANICS OF MATERIALS, Vol: 38, Pages: 571-584, ISSN: 0167-6636

Journal article

Ting SKM, Williams JG, Ivankovic A, 2006, Characterization of the fracture behavior of polyethylene using measured cohesive curves. I: Effects of constraint and rate, POLYMER ENGINEERING AND SCIENCE, Vol: 46, Pages: 763-777, ISSN: 0032-3888

Journal article

Ting SKM, Williams JG, Ivankovic A, 2006, Characterization of the fracture behavior of polyethylene using measured cohesive curves. III. Structure-property relationships, POLYMER ENGINEERING AND SCIENCE, Vol: 46, Pages: 792-798, ISSN: 0032-3888

Journal article

Ting SKM, Williams JG, Ivankovic A, 2006, Polyethylene using measured cohesive curves. II. Variation of cohesive parameters with rate and constraint, POLYMER ENGINEERING AND SCIENCE, Vol: 46, Pages: 778-791, ISSN: 0032-3888

Journal article

Brunner AJ, Blackman BRK, Williams JG, 2006, Calculating a damage parameter and bridging stress from <i>G</i><sub>IC</sub> delamination tests on fibre composites, Workshop on the Advances in Statics and Dynamics of Delamination, Publisher: ELSEVIER SCI LTD, Pages: 785-795, ISSN: 0266-3538

Conference paper

Williams JG, Hadavinia H, 2006, A cohesive zone global energy analysis of an impact loaded bi-material strip in shear, 11th International Conference on Fracture, Publisher: SPRINGER, Pages: 197-209, ISSN: 0376-9429

Conference paper

Obakponovwe O, Williams JG, 2006, Temperature effects on the fatigue of highly filled PMMA, JOURNAL OF MATERIALS SCIENCE, Vol: 41, Pages: 437-443, ISSN: 0022-2461

Journal article

Kawashita LF, Kinloch AJ, Moore DR, Williams JGet al., 2006, A critical investigation of the use of a mandrel peel method for the determination of adhesive fracture toughness of metal-polymer laminates, Engineering Fracture Mechanics, Vol: 73, Pages: 2304-2323, ISSN: 0013-7944

The application of peel tests for the measurement of adhesive fracture toughness of metal-polymer laminates is reviewed and the merits of a mandrel peel method are highlighted. The mandrel method enables a direct experimental determination of both adhesive fracture toughness (G(A)) and the plastic bending energy (G(P)) during peel, whilst other approaches require a complex calculation for G(P). In this method, the peel arm is bent around a circular roller in order to develop a peel crack and an alignment load attempts to ensure that the peel arm conforms to the roller. The conditions for peel arm conformance are thoroughly investigated and the theoretical basis for conformation are established. Experimental investigations involve the study of the roller size (radii in the range 5-20 nun are used), the peel arm thickness (varied from 0.635 to 2.0 mm) and the magnitude of the alignment load. In addition, the plane of fracture is studied since fractures can vary from cohesive to interfacial and this has a profound influence on the value of GA and on interpretation of results. A test protocol for conducting mandrel peel is developed such that the roller size for peel arm conformance can be established from preliminary fixed arm peel tests. The work is conducted on two epoxy/aluminium alloy laminates suitable for aerospace applications. Comparative results of adhesive fracture toughness from mandrel peel and multi-angle fixed arm peel are made with cohesive fracture toughness from a tapered double cantilever beam test. (c) 2006 Elsevier Ltd. All rights reserved.

Journal article

Blackman BRK, Brunner AJ, Williams JG, 2006, Mode II fracture testing of composites: a new look at an old problem, Engineering Fracture Mechanics, Vol: 73, Pages: 2443-2455, ISSN: 0013-7944

Journal article

Hadavinia H, Kawashita L, Kinloch AJ, Moore DR, Williams JGet al., 2006, A numerical analysis of the elastic-plastic peel test, Engineering Fracture Mechanics, Vol: 73, Pages: 2324-2335, ISSN: 0013-7944

The adhesive fracture energy, G., is determined from two types of elastic-plastic peel tests (i.e. the single-arm 90 degrees and T-peel methods) and a linear-elastic fracture-mechanics (LEFM) test method (i.e. the tapered double-cantilever beam, TDCB method). A rubber-toughened epoxy adhesive, with both aluminium-alloy and steel substrates, has been used in the present work to manufacture the bonded joints. The peel tests are then modelled using numerical methods. The overall approach to modelling the elastic-plastic peel tests is to employ a finite-element analysis (FEA) approach and to model the crack advance through the adhesive layer via a node-release technique, based upon attaining a critical plastic strain in the element immediately ahead of the crack tip. It is shown that this 'critical plastic strain fracture model (CPSFM)' results in predicted values of the steady-state peel loads which are in excellent agreement with the experimentally-measured values. Also, the resulting values of G(c), as determined using the FEA CPSFM approach, have been found to be in excellent agreement with values from previously-reported analytical and direct-measurement methods. Further, it has been found that the calculated values of G(c) are independent of whether a standard LEFM test or an elastic-plastic peel test method is employed. Therefore, it has been demonstrated that the value of the adhesive fracture energy, G(c), is independent of the geometric parameters studied and the value of G(c) is indeed a characteristic of the joint, in this case for cohesive fracture through the adhesive layer. Finally, it is noted that the FEA CPSFM approach promises considerable potential for the analysis of peel tests which involve very extensive plastic deformation of the peeling arm and for analysing, and predicting, the performance of more complex adhesively-bonded geometries which involve extensive plastic deformation of the substrates. (c) 2006 Elsevier Ltd. All rights reserved.

Journal article

Charalambides MN, Wanigasooriya L, Williams JG, Goh SM, Chakrabarti Set al., 2006, Large deformation extensional rheology of bread dough, Rheologica Acta, Vol: 46, Pages: 239-248, ISSN: 0035-4511

Journal article

Kinloch AJ, Hadavinia H, Kawashita L, Moore DR, Williams JGet al., 2006, A novel numerical method for analyzing peel tests, Florida, Proceedings of the 29th Annual Meeting of the Adhesion Society, 19 - 22 February 2006, Florida, USA, Publisher: Adhesion Society, Pages: 260-263, ISSN: 1086-9506

Conference paper

Kawashita LF, Moore DR, Williams JG, 2006, Protocols for the measurement of adhesive fracture toughness by peel tests, Journal of Adhesion, Vol: 82, Pages: 973-995, ISSN: 0021-8464

This article reports on the work of the European Structural Integrity Society Technical Committee 4 (ESIS TC4) and its activities in the development of test protocols for peel fracture. Thirteen laboratories have been working on peel test methods in ESIS TC4 since 1997 and their activities are ongoing. The aim of the work is to develop robust and credible test methods for the determination of adhesive fracture toughness by peel tests. Several geometric configurations have been used, namely, multi-angle fixed arm peel, T-peel, and roller assisted peel in the form of a mandrel test. The starting point of their work is an established analysis of a peel method that is often developed from a global energy approach. The adopted analysis is combined with an experimental approach in order to resolve ambiguities in the determination of adhesive fracture toughness (G(A)). The test methods involve the measurement of peel strength in order to calculate the total input energy for peel (G) and the calculation of the plastic bending energy (G(P)) during peel. The latter is often obtained from a measurement of the tensile behaviour of the peel arm. Adhesive fracture toughness is then G - G(P). Four ESIS TC4 projects are described. The first relates to fixed arm peel whilst the second and third involve both fixed arm and T-peel. The fourth project combines mandrel peel and fixed arm peel. Each project uses different types of polymeric adhesives in the form of quite different laminate systems. The selection of the laminate system enables all characteristics of laminate property to be embraced, for example, thin and thick adhesive layers, polymeric, and metallic peel arms and a range of flexibility in the laminates. The development of the enabling science required to establish the test protocols is described and software for conducting all calculations is referenced.

Journal article

Goh SM, Charalambides MN, Williams JG, 2005, Characterization of the nonlinear viscoelastic constitutive properties of mild cheddar cheese from indentation tests, JOURNAL OF TEXTURE STUDIES, Vol: 36, Pages: 459-477, ISSN: 0022-4901

Journal article

Rager A, Williams JG, Ivankovic A, 2005, Numerical analysis of the three point bend impact test for polymers, INTERNATIONAL JOURNAL OF FRACTURE, Vol: 135, Pages: 199-215, ISSN: 0376-9429

Journal article

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