The geometric deviations of real parts pose a major challenge, particularly in the extensively automated mass production of complex assemblies. To meet this challenge, an attempt is made, with the aid of statistical tolerance analysis, to predict dimensional accuracy for various assembly concepts as precisely as possible depending on the individual part tolerances. Most recent developments enable consideration to be given to the deformability of the parts during joining in order to improve the prognostic quality of simulation. The methods that are employed reveal deficits if nonlinear effects such as contact, extensive deformations, or material inelasticities occur. In this work, contact between or with adjacent parts during joining will be investigated, and an efficient and reliable method, which can be unproblematically integrated into existing compliant assembly variation analysis programs, will be developed. To achieve this, the methods of springback calculation according to Liu et al. (1995, “Variation Simulation for Deformable Sheet Metal Assemblies Using Mechanistic Models,” Trans. NAMRI/SME, 23, pp. 235–241) have been extended and coupled with numerical contact mechanics methods in order to realistically portray the problem, which usually involves intensive computing, with a minimum of additional effort. The method that has been developed will be validated on the basis of two examples with the aid of nonlinear finite element analyses, the results of which can be regarded as state-of-the-art in mechanical problems involving contact. The quality of the results reveals that this method improves the quality of prognosis for a wide range of applications and, consequently, that production problems can be combated during an early development phase.

Surface wear of corresponding tribological pairings is still a major problem in the application of artificial joint surgery. This study aims at developing wear reduced surfaces to utilize them in total joint arthroplasty. Using a pico-second laser, samples of medical CoCrMo metal alloy and Al2 O3 ceramic were patterned by laser material removal. The subsequent tribological investigations employed a ring-on-disc method. The results showed that those samples with modified surfaces show less mass or volume loss than those with a regular, smooth surface. Using calf serum as lubricating medium, the volume loss of the structured CoCrMo samples was eight times lower than that of regular samples. By structuring Al2 O3 surfaces, the wear volume could be reduced by 4.5 times. The results demonstrate that defined surface channels or pits enable the local sedimentation of wear debris. Thus, the amount of free debris could be reduced. Fewer abrasives in the lubricated so-called three-body-wear between the contact surfaces should result in less surface damage. Apart from direct influences on the wear behavior, less amounts of free debris of artificial joints should also be beneficial for avoiding undesired reactions with the surrounding soft tissues. The results from this study are very promising. Future investigations should involve the use of simulators meeting the natural conditions in the joint and in vivo studies with living organisms.

The technical aspects of manual total hip arthroplasty are briefly described. The development, technique and technical problems of previous robotic systems in total hip arthroplasty are described with special details of the Robodoc--System. Recent advances regarding the minimally invasive technique of total-hip implantation and navigation are described. The current development of a robotic assisted system for total hip arthroplasty is presented. This project aims to combine the advantages of minimally invasive techniques and navigational systems with the accuracy that robotic assisted bone milling can provide. The project-name is RomEo (Robotic minimally invasive Endoprosthetics), the main project partners are the Helmut-Schmidt-University/Hamburg and the Department of Trauma and Orthopaedics of the BG Trauma Hospital Hamburg.

Deficit and redundancies in existing automotive product development hinder a systems engineering based development. In this paper we discuss a methodical procedure to eliminate deficits in the current product development and in turn to enable the introduction of a new systems engineering based development methodology. As the core part of our approach, we discuss how to transform an opaque heterogeneous product development to a homogenous consistent product development taking into account existing disciplines. Our approach paves the way to achieve a process structure that is more amenable to verification and validation. We show the effectiveness of our proposed solution approach on an automotive use case.