Mechanical and microstructural characterization of titanium gr.5 parts produced by different manufacturing routes.

Since a few decades, the aircraft industry has shifted its preference for metal parts to titanium and its alloys, such as the high-strength titanium grade 5 alloy. Because of titanium grade 5 limited formability at ambient temperature, forming operations on this material requires high temperatures. In these conditions, a peculiar microstructure evolves as a result of the heating and deformation cycles, which has a significant impact on formability and product quality. On the other hand, additive manufacturing technologies, such as selective laser melting and electron beam melting, are increasingly being used and are replacing more traditional approaches such as machining and forging. Fundamental part characteristics such as mechanical and microstructural properties, geometric accuracy, and surface quality strongly depend on the selection of the manufacturing method. The authors of this paper seek to identify the strengths and limitations imposed by the intrinsic characteristics of different manufacturing alternatives for the production of parts of aeronautical significance, providing guidelines for the choice of the most appropriate manufacturing route for a given application and part design.

Workforce and supply chain disruption as a digital and technological innovation opportunity for resilient manufacturing systems in the COVID-19 pandemic.

During the SARS-CoV-2 pandemic (also known as COVID-19), workforce downsizing needs, safety requirements, supply chain breaks and inventory shortages affected manufacturing systems' and supply chain's responsiveness and resilience. Companies wandered in a disrupted scenario because recommended actions/strategies to survive - and thrive - were not available an improvised actions to keep their operations up and running. This paper analyzes the COVID-19 impacts on the workforce and supply resilience in a holistic manner. The following research questions are discussed: (i) how can manufacturing firms cope with urgent staff deficiencies while sustaining at the same time a healthy and safe workforce in the perspective of socially sustainable and human-centric cyber-physical production systems?; (ii) is remote working (cf. smart working) applicable to shop-floor workers?; (iii) is it possible to overcome supply chain breaks without stopping production? In the first part, we propose three Industry 4.0-driven solutions that would increase the workforce resilience, namely: (i) the Plug-and-Play worker; (ii) the Remote Operator 4.0; (iii) the Predictive Health of the Operational Staff. In the second part, the concepts of (i) Digital & Unconventional Sourcing, i.e. Additive Manufacturing, and (ii) Product/Process Innovation are investigated from a novel business continuity and integration perspective. We ultimately argue that forward-looking manufacturing companies should turn a disruptive event like a pandemic in an opportunity for digital and technological innovation of the workplace inspired by the principles of harmonic digital innovation (that places the human well-being at the center). These aspects are discussed with use cases, system prototypes and results from research projects carried out by the authors and real-world examples arising lessons learned and insights useful for scientists, researchers and managers.

Experimental Characterization of the Torsional Damping in CFRP Disks by Impact Hammer Modal Testing.

Composite materials are widely used for their peculiar combination of excellent structural, mechanical, and damping properties. This work presents an experimental study on the dissipation properties of disk-shaped composite specimens exploiting vibration tests. Two different polymer matrix composites with the same number of identical laminae, but characterized by different stacking sequences, namely unidirectional and quasi-isotropic configurations, have been evaluated. An ad-hoc steel structure was designed and developed to reproduce an in-plane torsional excitation on the specimen. The main idea of the proposed approach relies on deriving the damping properties of the disks by focusing on the modal damping of the overall vibrating structure and, in particular, using just the first in-plane torsional deformation mode. Experimental torsional damping evaluations were conducted by performing vibrational hammer excitation on the presented setup. Two methods were proposed and compared, both relying on a single-degree-of-freedom (SDOF) approximation of the measured frequency response function (FRF).