Advanced Manufacturing under Impact / Shock Loading: Principles and Industrial Sustainable Applications

Trends and developments in advanced manufacturing of advanced materials from macroto nanoscale subjected to static, lowspeed / high speed / hypervelocity impact and shock loading, with sustainable industrial applications to net-shape manufacturing, bioengineering, transport, energy and environment, defense and safety, an outcome of the very extensive, over 50 years, work on these scientific and industrial areas performed by the author and his research international team, are briefly outlined. The impact of such advanced materials, manufacturing and loading techniques, products and applications on many technological areas, e.g. the manufacturing/machine tool sector, communications / data storage, transportations, health treatment, energy conservation, environmental and human-life protection, is significant and highly beneficial. Introduction The topics considered, an outcome of the very extensive academic and industrial work over 50 years on these fields performed by the author and his research international team, may be listed as: • Mechanics (Structural plasticity, Low / High speed impact loading, Hypervelocity impact, Shockwaves loading) • Precision / Ultraprecision manufacturing from macro-, microto nanoscale (Metal forming, Metal removal processing, Surface engineering / Wear, Non-conventional techniques) • Nanotechnology / Nanomaterials manufacturing • Ferrous and non-ferrous materials (Metals, Ceramics, Superhard, Polymers, Composites, Multifunctional), from macroto nanoscale (Nanostructured materials, Nanoparticles, Nanocomposites) • Powder production and processing technologies (High strain-rate phenomena and treatment under shock: Explosives, Electromagnetics, High temperature / high pressure techniques) • Biomechanics / Biomedical engineering • Transport / Crashworthiness of Vehicles: Passive and active safety for passengers and cargo (Surface transport: Automotive, Railway; Aeronautics: Aircraft, Helicopters) • Energy (Superconductors, Semiconductors, Electromagnetics, Solar cells, Photovoltaics, Nuclear reactors) • Environmental aspects (Impact on climate change: Nanotechnology; Automotive industry; Aeronautics industry) • Safety (Detection of explosives and hazardous materials) • Defense (Ballistics, Projectiles hitting targets, Shock loading) Explosion Shock Waves and High Strain Rate Phenomena Materials Research Forum LLC Materials Research Proceedings 13 (2019) 13-24 https://doi.org/10.21741/9781644900338-3 14 • Industrial sustainability Some trends and developments in Advanced Manufacturing from macroto nanoscale in the important engineering topics from industrial, research and academic point of view: nanotechnology, precision /ultraprecision engineering and advanced materials (metals, ceramics, polymeric, composites/nanocomposites) under static, low/high speed impact, hypervelocity impactand shock loading, with sustainable industrial applications to net-shape manufacturing, bioengineering, transport, energy/environment and defense / safety, are briefly outlined in the present ESHP 2019 Invited Lecture. Manufacturing Technology Principles The principles of advanced manufacturing technology may be identified by six main elements, see Fig. 1, with the central one being the enforced deformation to the material, i.e. the processing itself, brought about under consideration of the interface between tool and workpiece, introducing interdisciplinary features for lubrication and friction, tool materials properties and the surface integrity of the component. The as-received material structure is seriously altered through the deformation processing, subjected from static to very high-strain rate phenomena / shock loading, therefore, materials testing and quality control before and after processing are predominantly areas of interest to the mechanics, manufacturing and materials scientists. The performance of the machine tools together with the tool design are also very important, whilst, nowadays, the techno-economical aspects, like the notion of manufacturing systems, e.g. automation, modeling and simulation, rapid prototyping, process planning, computer integrated manufacturing, energy conservation and recycling, as well as environmental aspects are important in advanced manufacturing engineering [1]. Fig. 1 Advanced manufacturing technology principle Explosion Shock Waves and High Strain Rate Phenomena Materials Research Forum LLC Materials Research Proceedings 13 (2019) 13-24 https://doi.org/10.21741/9781644900338-3 15 The structural plasticity mechanics, governing the deformation of the material, see Fig. 2, are mainly associated with [1, 2]: (a) Low strain-rate phenomena, i.e. deformation under static-, low speed impact loading, for metals, polymers and composite materials, see Fig. 2(i). In this case, the material behavior is characterized by its stress-strain curve. Ductile metals and polymers are plastically deformed with the formation of stationary and traveling plastic hinges. Contrary to this ductile mechanism, the deformation mechanism for brittle composite materials is achieved by material fragmentation developing extensive microcracking processes easily controlled and depended on the properties of fibers and resins the fibers orientation. Fig. 2Structural plasticity mechanics (b) High strain-rate phenomena, i.e. deformation under high speed / hypervelocity impact-, shockwaves loading), for metals, ceramics and superhard materials (diamonds, CBN), see Fig. 2(ii). During dynamic / shock loading, a longitudinal, P-shockwave, with a real shockwave profile (pressure, P vs time, t), is initiated, traveling into the body at high speed, calculated from the corresponding state of the material under shock conditions, i.e. its Hugoniot curve (pressure, P specific volume, V relationship), defined as the loci of all shock states and essentially describing the material properties. The particles are accelerated into the pores at high velocities, impacting each other, which results in the development of shear S-waves in the particles due to jet impact at a point on the particle surface, traveling inside the particle and reflected at its surface resulting in jet formation due to spalling, with subsequent loading of the already formed jet moving between the interparticle voids in the same direction as the shock. The frictional energy release results, Explosion Shock Waves and High Strain Rate Phenomena Materials Research Forum LLC Materials Research Proceedings 13 (2019) 13-24 https://doi.org/10.21741/9781644900338-3 16 therefore, in melting at the surface regions with the associated bonding once the material is solidified. In the consolidation of brittle materials, particle fracture also occurs, leading to the filling of the gaps, whilst reactive elements can also be added to help the bonding process. The high-pressure state creates numerous lattice defects and dislocation substructures leading very often to localise shearing and microcracking. The energy dissipation modes due to shockwaves and the relevant mechanisms, are related to the shock released energy, E = 1⁄2 P (V-V0), where P is the peak shock pressure, V0 the initial specific powder volume and V the volume of the solid material. Quality of manufactured parts is mainly determined by their dimensional and shape accuracy, the surface integrity, and the functional properties of the products. Development of manufacture engineering is related to the tendency to miniaturization and is accompanied by the continuous increasing of the accuracy of the manufactured parts. The two main trends towards the miniaturization of products are, see Fig. 3: • Precision/ Ultraprecision manufacturing (Metal forming, Metal removal processing, Surface engineering / Wear, Non-conventional techniques), see Fig. 3(i), carried out by machine tools with very high accuracy; • Nanotechnology processing, see Fig. 3(i), i.e. the fabrication of devices with atomic and / or molecular scale precision by employing new advanced energy beam processes that allow for atom manipulation and therefore, the design and manufacture of the nanostructured materials, having every atom or molecule in a designated location and exhibiting novel and significantly improved physical, chemical, mechanical and electrical properties. The various stages of nanomaterials manufacturing are listed in Figure 3(ii) [3].