In this fourth issue of Engineering and Computational Mechanics we are again aiming to present the diversity of computer methods and their applications in civil engineering mechanics. The civil engineering community has contributed significantly to the development and use of computer methods in engineering. Indeed, many pioneers of the finite-element method, such as Ray Clough and John Argyris to name but a few, have a background in civil engineering or structural engineering. The early works on computational mechanics exhibit an admirable blend of mathematical rigour with an appeal to intuitive understanding. To me personally, Einstein's phrase, ‘make everything as simple as possible, but not simpler’ always sounded very true but at the same time it seemed somewhat impenetrable and elusive for the uninitiated. It can perhaps be interpreted as a comfortable balance between fundamentals and applications – one without the other could never become ‘as simple as possible’. Einstein's phrase assumed true meaning when I read the early civil engineering textbooks on finite-elements of the 1960s and the 1970s. These texts often jump seamlessly from variational calculus to first principles and back. There are good mathematical reasons as well as good structural engineering reasons why the components of a single row or column of a finite-element stiffness matrix must add up to zero.
The balance between fundamentals and applications is reflected in this new issue of the Proceedings of the Institution of Civil Engineers. The topic of the first paper, by Metje et al., is how to determine structural deflections from measured strains. The basic operations from matrix method structural analysis are manipulated in an elegant manner, and two methods are suggested for the prediction of displacements of frames.
In the second paper, Driss et al. study the dynamic behaviour of gears by a time-dependent variation of the stiffness matrix of the system, using time domain as well as frequency domain analysis. The influence of defects becomes manifest as an amplitude modulation.
Yang et al. simulate bacterial transport in the third paper. The governing equations are of the transport type, accounting for advective and diffusive effects. The model is then used to make predictions on bacteria levels in the area of the Bristol Channel and the River Severn (UK).
In the final paper, Fang et al. develop a numerical model that can be used to describe concrete fracture. The finite-element formulation is based on the XFEM methodology, and it ensures finite-energy dissipation through a cohesive model of the crack. The formulation is able to simulate experimental results of a beam with a single notch under skew-symmetric fourpoint loading – a test that has for decades been a true challenge to many numerical analysts.
