David Ewins
Imperial College London, and
BLADE, University of Bristol
Dramatic developments have taken place in structural dynamics over the past two decades. Many of today’s capabilities, such as finite element modelling of complex components, exceed the greatest expectations of earlier times but the developments have been uneven across the different types of activity: in particular, computational methods have improved and expanded to a much greater extent than have experimental methods. However, they do not – and for the foreseeable future in many areas, will not – completely eliminate the need for practical testing as the final proof of a structural design. It is increasingly clear that we need to find a new balance between the two primary approaches to the subject: theoretical and experimental.
Against this background, this talk presents a strategic review of the current status of the subject of structural dynamics and of the challenges and expectations which confront the structural dynamicist today, with particular reference to the aerospace and other hi-tech industries. Three particular areas are highlighted as representing major obstacles to further significant progress towards the goal of designing for structures and machines which fully comply with the demands of dynamic performance. These areas are:
(i) the relative inability to model the joints and interfaces which connect the components in almost all structures and machines;
(ii) the need for a radically new approach to the validation of theoretical models using test data and
(iii) the growing importance of uncertainty and variability issues (‘uncertainty’ or scatter in the dimensions of nominally-identical products; ‘variability’ in their dynamic characteristics resulting from the uncertainty) which are essential for reliable and robust design.
Ways forward for each of these critical issues are proposed.
