Integrated simulation of the process chain composite extrusion–milling–welding for lightweight frame structures

Generally, the manufacturing of lightweight frame structures involves various processes that yield the final product. Simulation methods can be used to optimise the different process steps. When chaining these process steps together in the simulation, software interfaces become necessary to realise an integrated virtual process chain. In this paper two approaches are presented that solve this issue and demonstrate it for an exemplary part. Different software tools with appropriate interfaces and the use of only one software tool for the simulation of the whole process chain are investigated respectively. The results of both approaches are analysed and relevant conclusions are deduced.     

Interaction of finger representation in the human first somatosensory cortex: a neuromagnetic study

The authors studied immunologic features of saliva in 1714 workers exposed to vibration and other occupational hazards in microbiologic, chemical enterprises. The examinees demonstrated lower activity of lysozyme and concentrations of IgA, higher levels of IgG. Immunologic features of saliva was proved to have extreme diagnostic importance, therefore could be used to detect early signs of exposure to occupational hazards and to diagnose pathologic conditions caused by those hazards.     

A low cycle fatigue model of a short-fibre reinforced 6061 aluminium alloy metal matrix composite

A low cycle fatigue model has been developed to predict the fatigue life of both the unreinforced aluminium alloy and the short-fibre reinforced aluminium alloy metal-matrix composites based solely on crack propagation from microstructural features. In this approach a crack is assumed to initiate and grow from a microstructural feature on the first cycle. The model assumes that there is a fatigue-damaged zone ahead of the crack tip within which the actual degradation of the material takes place. The low-cycle fatigue crack growth and the condition for failure are controlled by the amount of cyclic plasticity generated within the fatigue-damaged zone ahead of the crack tip and by the ability of the short fibres to constrain this cyclic plasticity. The fatigue crack growth rate is directly correlated to the range of crack-tip opening displacement. The empirical Coffin–Manson and Basquin laws have been derived theoretically and applied to compare with total-strain controlled low-cycle fatigue life data obtained on the unreinforced 6061 aluminium alloy at 25 °C and on the aluminium alloy AA6061 matrix reinforced with Al₂O₃ Saffil short-fibres of a volume fraction of 20 vol.% and test temperatures from −100 to 150 °C. The proposed model can give predicted fatigue lives in good agreement with the experimental total-strain controlled fatigue data at both high strain low-cycle fatigue and low strain high-cycle fatigue regime. It is remarkable that the addition of high-strength Al₂O₃ fibres in the 6061 aluminium alloy matrix will not only strengthen the microstructure of the 6061 aluminium alloy, but also channel deformation at the tip of a crack into the matrix regions between the fibres and therefore constrain the plastic deformation in the matrix. The overall expected effect is therefore the reduction of the fatigue ductility.     

Mouse Selection Versus Voice Selection of Menu Items

Subjects completed a menu selection task using mouse and spoken language technologies for menu sizes that are powers of 2 from 2 to 256. It was found that mouse selection was faster than spoken language selection for menu sizes of 32 or less for most subjects. For small N, mouse selection was about three times faster. Spoken language selection was as fast or faster for menus of size 64 or larger. The trade-off size, approximately 64, was different for various subjects, but not greatly different. Data was gathered for words with one, two, and three syllables with the result that the trade-off size was the same for all three, but the error characteristics for spoken inputs were worse for shorter words, as would be expected.     

A non-rigid registration method for the efficient analysis of shape deviations in production engineering applications

A common requirement in production engineering applications is the comparison of designed and as-built parts. Due to manufacturing influences and geometric changes incorporated during physical prototyping, there may exist significant deviations between these shapes. In order to compensate the manufacturing influences and to incorporate geometric changes into the virtual design, a detailed analysis of the deviations is required. The designed (or reference) shape is usually given in terms of a CAD data set, while the as-built (or test) geometry is acquired by digitization of the physically manufactured prototype. Given these two geometries, one is faced with the problem of determining points of correspondence between them. This is also referred to as registration. In rigid registration, correspondences are determined by first aligning the two geometries rigidly using a best-fit approach. Subsequently, the correspondences between the aligned geometries are determined by finding for a point of one shape the closest surface point on the other. While several efficient rigid registration methods exist, they do not account for shape deviations, resulting in inaccurate correspondences when applied to such geometries. Non-rigid registration methods, conversely, do not search for a global best-fit alignment, but instead affect a deformation of the one geometry onto the other, allowing for an improved correspondence calculation. Most published state-of-the-art non-rigid registration methods are not necessarily applicable to production engineering scenarios due to, among others, the typical data sizes and the required level of accuracy in the correspondence determination. A further hindrance is their lack of shop-floor applicability, attributable to their calculation times as well as to the expertise that their application requires on behalf of the user. This paper presents a non-rigid registration method for the efficient calculation of correspondences in production engineering scenarios. By combination of several established methods from the field of geometric modeling, the test shape is iteratively deformed onto the reference shape. When the deformed test shape satisfiably approximates the reference geometry, correspondences are determined by projection. The procedure is applied to the problem of springback behavior, which arises in sheet metal forming. A validation of the method is achieved by comparing the calculated correspondences with the ideal correspondences, as determined by finite element simulation.     

The impact of autonomous vehicle technologies on product recall risk

Complex Advanced Driving Assistance Systems (ADAS) and Autonomous Vehicle (AV) technology are increasing the number of vehicle recalls. At the same time, financial risks resulting from extensive product recall events can severely affect vehicle manufacturers and their suppliers, exposing the automotive supply chain to business continuity, legal and reputational risk. However, these risk implications are under-appreciated by large segments of the supply chain. This study shows that product recall events are increasing in general but recall events associated with ADAS/AV technology form an increasingly large percentage of these recall events. Based on this analysis, we describe ADAS/AV-specific aspects of risk mitigation and present a multidimensional approach, combining production-centric risk mitigation avenues in the automotive supply chain with the transfer of residual financial risks via insurance. We find that this comprehensive risk mitigation approach benefits in higher transparency of total production costs and increased resilience of the automotive supply chain. Against the background of an increasing product recall risk resulting from the increasing automation and interconnectedness of modern vehicles, we therefore suggest a closer, more strategic cooperation between insurance companies, car manufacturers and automotive suppliers for the benefit of all parties.     

Modelling and simulation of process: machine interaction in grinding

This article presents an overview of current simulation methods describing the interaction of grinding process and grinding machine structure, e.g., vibrations, deflections, or thermal deformations. Innovative process models which describe the effects of the grinding wheel–workpiece interaction inside the contact zone are shown in detail. Furthermore, simulation models representing the static and dynamic behaviour of a grinding machine and its components are discussed. Machine tool components with a high influence on the process results are modelled more detailed than those with low influence. The key issue of the paper is the coupling of process and machine tool models for predicting the interactions of process and machine. Several coupling methods are introduced and the improvements of the simulation results are documented. On the basis of the presented simulation approaches, grinding processes and machines can be designed more effectively resulting in higher workpiece quality and process stability.