In forming processes, friction is a local phenomenon influenced by the contact conditions at the tool-sheet metal interface. A multi-scale friction model applicable for coated sheets is developed for ...the boundary lubrication regime which accounts for the physical behavior of coating and measured surface topographies of sheet and tools. The contact patches and therefore the real area of contact is determined at the tool-sheet metal interface for different contact loading conditions. A single asperity micro-scale ploughing model is adapted at each contact patch to determine the friction force from which the overall coefficient of friction is determined. The friction model is validated using different sets of lab-scale friction tests and cup drawing experiments on zinc coated (GI) steel sheets.
•1.A multi-scale friction model is developed for the boundary lubrication regime.•2.Applicable for coated sheets and accounts for physical behavior of the coatings.•3.Surface topographies of sheet and tools are used as the input in the model.•4.Single asperity ploughing model is adopted at macro-scale deformed sheet surface.•5.The model is validated using lab-scale friction tests and cup drawing experiments.
Metal forming process is one of the oldest manufacturing techniques. It has witnessed the shift from conventional to integration of smart systems for manufacturing of highly complex components. Many ...mathematical, experimental and simulation software techniques are discussed. Servo press is the most indispensable machine used for the manufacturing of delicate parts of automobile, aviation industry with high accuracy. The main motive of replacing or modifying the prevailing conventional manufacturing techniques into modern, smart and sustainable manufacturing like industry 4.0 is to become more competitive and to adopt customization & sustainability. Integration of industrial internet of things (IIoT) with automated supply chain has given optimized productivity, quality, and economical feasibility. This manuscript throws some light on different metal forming process, servo press application in automobile, aviation industry and different components require to make metal forming smart and sustainable in term of industry 4.0.
We study, experimentally and theoretically, the mechanical response of sheet materials on which line cracks or cuts are arranged in a simple pattern. Such sheet materials, often called kirigami (the ...Japanese words, kiri and gami, stand for cut and paper, respectively), demonstrate a unique mechanical response promising for various engineering applications such as stretchable batteries: kirigami sheets possess a mechanical regime in which sheets are highly stretchable and very soft compared with the original sheets without line cracks, by virtue of out-of-plane deformation. However, this regime starts after a transition from an initial stiff regime governed by in-plane deformation. In other words, the softness of the kirigami structure emerges as a result of a transition from the two-dimensional to three-dimensional deformation, i.e., from stretching to bending. We clarify the physical origins of the transition and mechanical regimes, which are revealed to be governed by simple scaling laws. The results could be useful for controlling and designing the mechanical response of sheet materials including cell sheets for medical regeneration and relevant to the development of materials with tunable stiffness and mechanical force sensors.
Modelling of metal forming processes is an essential task of production engineering. Due to the latest technological developments, a huge variety of models is already available and extending ...continuously. Thus, it is important to find a suitable model. This paper gives an overview on the common classification and characterization of modelling and models in metal forming, as well as introduces a model selection procedure. Based on this classification, various relevant process limits for metal forming are investigated regarding existing models. The conclusion of the paper shows open topics as well as upcoming challenges in modelling process limits in metal forming.
Metal forming is not only shaping the form of a product, it is also influencing its mechanical and physical properties over its entire volume. Advanced analysis methods recently enable accurate ...prediction of these properties and allow for setting these properties deterministically during the forming process. Effective measurement methods ensure the setting of these predicted properties. Several real examples demonstrate the impressive achievements and indicate the necessity of a paradigm change in designing products by including manufacturing-induced effects in the initial dimensioning. This paradigm change will lead to lightweight components and serve environmentally benign designs.
This paper reviews studies on the prediction of ductile fracture during metal forming using an ellipsoidal void model and some other models proposed by the author and some relevant studies. Section 2 ...discusses the research on the theory of voids for predicting ductile fracture during metal forming. Section 3 summarizes the simulation method for predicting ductile fracture during metal forming using the ellipsoidal void model, and Section 4 summarizes the simulation result on the ductile fracture prediction during metal forming using the ellipsoidal void model. Section 5 shows the applicability of the ellipsoidal void model and the simulation result on the ductile fracture prediction during metal forming using some other models.
This paper reviews studies on the prediction of ductile fracture during metal forming using an ellipsoidal void model and some other models proposed by the author and some relevant studies. Section 2 ...discusses the research on the theory of voids for predicting ductile fracture during metal forming. Section 3 summarizes the simulation method for predicting ductile fracture during metal forming using the ellipsoidal void model, and Section 4 summarizes the simulation result on the ductile fracture prediction during metal forming using the ellipsoidal void model. Section 5 shows the applicability of the ellipsoidal void model and the simulation result on the ductile fracture prediction during metal forming using some other models.
Damage in metal forming Tekkaya, A.E.; Bouchard, P.-O.; Bruschi, S. ...
CIRP annals,
2020, 2020-00-00, Letnik:
69, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Physical mechanisms of ductile damage in metal forming, experimental characterization methods for damage, and models predicting the damage level in formed components are reviewed. Applications of ...damage analysis in metal forming processes reveal that damage in metal formed parts is not failure, but a product property that accumulates between processes. Various metal forming process designs demonstrate that damage in formed products can be reduced and their performance can be increased. Static and fatigue strength, impact toughness, stiffness, and formability are typical examples of performance indicators that can be improved by damage-based process design. Potential scientific and technological challenges are addressed to realize damage-controlled metal forming processes.
Many high temperature (HT) forming processes require the use of solid lubricants in order to control friction and reduce wear. In an attempt to eliminate the need for solid lubrication in high ...temperature sliding applications, nickel-based self-lubricating coatings with the addition of Ag and MoS2 were prepared by means of laser cladding on stainless steel substrates.
The behaviour of the resulting laser claddings was thoroughly evaluated up to 600 °C, including the oxidation behaviour and reciprocating tribotesting using different counter body geometries (ball and flat pin). The self-lubricating coatings showed lower friction than the unmodified reference alloy at all tested temperatures, in addition to a significant microstructural stability after prolonged exposure at high temperatures. The addition of solid lubricants to the claddings was also found to be beneficial in terms of the counter body wear at HT, as no material loss could be measured for the bearing balls after testing at 600 °C against the self-lubricating claddings, despite the significant softening experienced by AISI 52100 bearing steel at HT.
•The encapsulation by sulfur-rich phases prevented silver depletion at HT.•Oxidation tests at 600 °C showed no changes to the cladding 5 Ag – 10 MoS2.•The self-lubricating claddings showed lower friction than the reference alloy.•Changes in tribological behaviour were seen for ball and flat counter bodies.•Tool steel counter bodies led to severe wear for the reference alloy.
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