Abstract Aeronautical companies are manufacturing many components of small (less than 200 mm) and medium (between 200 mm and 1000 mm) sizes by flexforming. In order to diversify the production facilities of these components, these companies are interested in evaluating the ability of electromagnetic forming processes to produce small parts. This paper describes the design of a set of experiments of

Abstract Full range constant strain rate tests are required for accurately characterizing initial yield point, strength differential effect and direct identification of constitutive laws describing the plastic behavior of materials. These tests require the use of a closed-loop control in order to achieve the constant strain rate, however this feature is not available in many laboratories. A method

Abstract Voids occurred after the manufacturing process are a common defect of composite materials. They appear to have a negative impact on the matrix-dominated material properties, the gravity of which depends upon the porosity content, the shape and the volume of pores. In the present work, the effects of porosity on the shear mechanical properties of unidirectional carbon fiber-reinforced plastic

Abstract Self-reinforced polypropylene (SRPP) is a composite in which the reinforcement and the matrix consist of the same polymer, namely polypropylene. The present work focuses on the development and experimental validation of an FE model for thermoforming of SRPP. The constitutive model of SRPP sheet is based on the Boisse – Charmetant hyperelastic law. Material properties required to fit the model

Abstract This paper investigates the manufacture of biaxial carbon fiber braids and the influence that different machine settings have on variability of the textile architecture produced. In parallel, numerical simulations of the braiding process with these different machine settings have been conducted. For these studies yarn tension and process speed are varied to generate cylindrical biaxial braids

Abstract This paper proposes an innovative electromagnetic forming process for the manufacturing of aluminum alloy tubes, namely electromagnetic impacting medium forming (EIMF) process using flat spiral coil. The proposed EIMF process was implemented and characterized by numerical and experimental methods. Based on medium height and discharge energy, deformation region of tube was analytically determined

Abstract Recent advances in mechanical and civil engineering are noticed in many innovative designs that frequently employ cold-formed High Strength Steels (HSS). Typical mobile cranes benefit from the advanced properties of these steel grades in a bent configuration. Here, the majority of load-carrying members are produced through cold-bending and subsequent welding procedures. These cold-foring processes

Abstract The quality of thin strip products is determined by the flow and heat transfer in a molten pool of twin-roll casting, thus it is of great significance to study the structure parameters of the delivery system, including the angle and height of end face nozzle, the angle and height of side nozzle as well as the taper angle of side nozzle. A methodology for simulation of twin-roll thin strips

Abstract The limited capability to predict material failure in composite materials and specifically in wavy composite layers has led to high margins of safety for the design of composite structures. Thus, the full lightweight potential of this class of materials is left unused. To understand the complex failure behavior of composite materials containing out-of-plane fiber waviness under compressive

Abstract Reliable sheet metal forming simulations depend on accurate descriptions of real process conditions. These conditions include material behavior, lubrication systems, tool deformations, press dynamics, and more. Research on material models is the most mature area for describing these conditions in a reliable way. Several advanced and flexible models exists. This study focuses on two versions

Abstract The hot deformation behaviour of one 7XXX series aluminium alloy, 7A04, has been studied by conducting isothermal hot compression tests with degree of compression up to 55% at the temperature ranging from 350 °C to 480 °C and strain rates ranging from 0.002 s−1 to 20s−1. Based on characteristic of the flow stress obtained from those tests, an extended Voce equation, which constant parameters

Abstract Hole flanges are commonly manufactured in mass production by conventional press-working. In an industrial context, the process limits are usually evaluated by means of the Limiting Forming Ratio (LFR), which defines the maximum attainable diameter of the flange related to the initial pre-cut hole. Nevertheless, the LFR does not provide enough information about material deformation, thickness

Abstract Radial-Axial Ring Rolling (RARR) is an industrial forging process for making strong, seamless metal rings. Conventionally, rings are made circular with constant cross-section. In this work we demonstrate a sensing and control strategy to create rings with variable radial wall thickness and variable curvature using standard RARR hardware. This has a number of potentially useful applications

Abstract In this study, to eliminate the extrudate swell, melt fracture and extrudate distortion problems of polypropylene (PP) micro-tube, the experiments of gas-assisted extrusion forming was firstly carried out. Meanwhile, a set of modified gas-assisted extrusion system was set-up, and a kind of novel gas-assisted die was also designed and manufactured. Under the role of gas-assisted extrusion system

Abstract To accurately model warm and hot forming operations, correct values for heat transfer coefficient (HTC) are required, among other parameters. In this work, an experimental methodology is proposed to obtain HTC data for a high strength steel alloys (Usibor® 1500 A-S), seven aluminum alloys (AA5182-O, AA5754-O, AA6013-T6, AA6063-T6, AA6061-T6, AA7075-T6 and a developmental AA7xxx-T76) and two

Abstract A new analytical method to determine the effective tool width in contact with the sheet workpiece in the plane strain compression test, which changes during the test if a tool with a radius is used, is proposed. A detailed description of this method and the corresponding procedure of the flow curve determination for high-strength sheet steels are presented. The underpinning assumptions of

Abstract The optimization of extrusion of energetic materials is a complex topic that requires the knowledge of the material behaviour in the processing conditions selected for this forming process. During the rheological characterization of multi-base colloidal propellants (nitrocellulose gels), certain mechanisms, such as apparent wall slip and loss of solvents, provoke a significant distortion on

Abstract This paper proposes a heuristic and genetic approach for cutting sheet metal parts that identify effective locations for micro-joints, thereby generating an optimized tool path. In the current industrial practice of Laser, Plasma and Abrasive Water Jet (AWJ) processes, one or more micro-joints (also known as a stitch) are used to link the cut parts with the sheet. These micro-joints are randomly

Abstract In order to improve the roundness of continuously variable wall conical rotatory parts, this paper aims to achieve precision forming of such sheet-metal casing part. The true stress-strain equation of GH3030 superalloy at normal temperature is established by experimental methods. On this basis, a power spinning finite element model about GH3030 superalloy continuously variable wall conical

Abstract The mechanical behavior of zinc alloys drastically depends on strain rate and temperature, which are not constant during forming processes. During the production of zinc sheets, the slight variations of the industrial equipment parameters induce different local thermomechanical conditions. These variations could be stemming from a non-homogeneous cooling during rolling process, or local segregation

Abstract The present study helps in providing a systematic approach towards the investigation of deep drawing and stretch forming processes for Inconel 625 alloy. Firstly, the flow stress nature and material properties of Inconel 625 super-alloy have been investigated and it has been found that temperature and deformation rate significantly affects the flow stress behavior. By using experimental flow

Abstract Formability predictions of Ti6Al4V titanium alloy sheets deformed at room temperature and 600 °C, using D-Bressan’s shear stress rupture criterion and the critical strain gradient macroscopic modelling are presented and discussed in relation to limit strain results obtained experimentally. Ti6Al4V Forming Limit Strain Curves were predicted and compared with experimental curves at 25 °C and

Abstract Finite element modeling of machining aims for guidance in the choice of the cutting parameters and for the comprehension of the involved phenomena. The modeling of the behavior of the machined material is a key parameter to develop a realistic model. It is nowadays still extremely difficult to acquire experimental data on the material flow stress due to the extreme conditions encountered during

Abstract The texture evolution of copper tube manufactured by floating plug drawing process was investigated by Electron Backscatter Diffraction techniques and Visco-Plastic Self-consistent (VPSC) modelling method. The results obtained from experimentation indicate that the initial textures of copper tube transformed sharply after the first pass of the drawing process, and the final textures in the

Processing tubes from poly (l-lactic acid) (PLLA) by stretch blow moulding (SBM) is used in the manufacture of bioresorbable vascular scaffolds (BVS) to improve their mechanical performance. To better understand this processing technique, a novel experimental setup by free stretch blow inside a water bath was developed to visualise the tube forming process and analyse the deformation behaviour. PLLA

Abstract Incremental sheet-bulk metal forming (iSBMF) enables the manufacture of functional lightweight components featuring a load-adapted shape with a high material efficiency. The flexibility of the incremental forming process allows for the modification of the strain path through the adjustment of the tool motion while maintaining the final product geometry. These modifications generate both a

The paper presents the analysis of hot deformation behavior of Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) alloy using the theory of dynamic material modeling (DMM) based on hot compression tests performed to a total true strain of 1 at the strain rates from 0.01 to 100 s−1 and at the temperatures within the range between 800 and 1100 °C. The processing maps according to the Prasad’s criterion were developed. The

Abstract It is worthy to investigate how it will affect the parameters calibration using an average stress state variable before the practical application of a ductile fracture criterion. In order to study this problem, ten notch specimens of AA7075-T6 sheet were designed to implement the tension tests and a parallel simulation of each test was run to obtain the variation of related variables such

In the original publication of this paper, an incorrect image of Figure 3 was used in error.

Abstract Large components, for instance in the energy industry, mining and heavy machinery, are produced from high weight cast as ingots followed by open-die forging. Besides achieving a certain final geometry and microstructure, one of the main objectives during the forging process is the elimination of casting defects, like voids from the solidification shrinkage. This process is divided in the two

Additive manufacturing is the more and more considered in industry, however efficient simulation tools able to perform accurate predictions are still quite limited. The main difficulties for an efficient simulation are related to the multiple scales, the multiple and complex physics involved, as well as the strong dependency on the process trajectory. This paper aims at proposing a simplified parametric

Abstract A numerical methodology is proposed to predict void content and evolution during autoclave processing of thermoset prepregs. Starting with the initial prepreg void content, the void evolution model implements mechanisms for void compaction under the effect of the applied pressure, including Ideal Gas law compaction, and squeeze flow for single curvature geometries. Pressure variability in

Abstract In bubble assisted vacuum thermoforming, measuring pressure-induced mechanical strains through the stereo-digital image correlation (stereo-DIC) technique while shaping thermoplastic sheet requires consideration of an appropriate reference state of surface deformations. However, when the stereoscopic measurements can be only performed after the heating step, the correlation problem should

Abstract To simulate the behaviour of textiles, three major characteristics are important, kinematic fibre interaction, shear behaviour, and thickness changes of the fabric caused by shearing. Instead of anisotropic continuum mechanical models normally used, a macroscopic finite element coupled with an internal unit cell, made of beam elements is proposed here. The beam elements represent the yarns

Hemming is the main assembly process used for auto-body panels. Surface defects resulting from the hemming operation may significantly influence the appearance aesthetics of an automobile. The formation of surface defects can be forestalled, and the process can be optimized and compensated by the numerical simulation method during the process design stage. In this study, the hemming assembly of a fuel

Bioresorbable Vascular Scaffolds (BVS) manufactured from poly (l-lactic acid) (PLLA) offer an alternative to metal scaffolds for the treatment of coronary heart disease. One of the key steps in the manufacture of these scaffolds is the stretch blow moulding process where the PLLA is biaxially stretched above glass transition temperature (Tg), inducing biaxial orientation and thus increasing ductility

Abstract Springback simulation of stamped sheet metal components using finite element method depends on the accuracy of appropriate material models and consideration of appropriate experimental strategies. In this work, tension-compression tests with different strategies, e.g. tension-compression, compression-tension up to various strain levels and multicycle compression-tension tests were conducted

Abstract To this day, the design of preforms for hot forging processes is still a manual trial and error process and therefore time consuming. Furthermore, its quality vastly depends on the engineer’s experience. At the same time, the preform is the most influencing stage for the final forging result. To overcome the dependency on the engineer’s experience and time-consuming optimization processes

Forming nickel-based superalloy aero-engine components is a challenging process, largely because of the risk of high degree of springback and issues with formability. In the forming tests conducted on alloy 718 at room temperature, open fractures are observed in the drawbead regions, which are not predicted while evaluating the formability using the traditional forming-limit diagram (FLD). This highlights

In the present paper, finite element simulations are used to gain a better understanding of the setting process of a blind rivet nut. A blind rivet nut is a mechanical fastener capable of clinching materials whilst providing a threaded solution without the need for thread forming. The technique relies on plastic deformation introduced by axial compression of the rivet nut in such a way that a counter

This paper presents an experimental study of the effect of mesoscopic buckles defect and reinforcement shear, which result from forming, on the low velocity impact behavior of a composite laminate. The material studied is a glass/polyester composite with three layers of mat and one layer of taffeta fabric. To assess the properties induced on the final composite, plates with different amplitudes of

The possibility to study and clearly define the physics phenomena that occur during the machining process of various metal materials is becoming one of the interpretative keys to quantify a product’s quality and life cycle performance. An accurate understanding of the surface integrity can be achieved through the knowledge of the fundamental details about the mechanical response and the behaviour of

Abstract Formability of a continuous fiber-reinforced material is known to be influenced by its intraply shear behavior. This study investigates a 2 × 2 twill weave carbon fabric and the corresponding vinyl-based thermoset prepreg developed for press-cured structural parts. Intraply shear tests of bias-extension and picture-frame were conducted for a range of industrial-relevant processing conditions

Abstract Dimensional analysis is performed as a method to evaluate the characteristics of superplastic forming processes. The analysis is focused on the forming time results from superplastic free bulge tests so that an estimator for the forming time is obtained based on dimensionless parameters. The dimensional analysis is performed by applying the normalisation to the dynamic equations and their

Abstract In the last decades, new flexible manufacturing processes have been developed to face the demands, by many industrial fields, for highly customized complex functional parts. The peculiar design of these components often overcomes conventional sheet metal and bulk metal forming processes capabilities. In order to face this issue, new hybrid techniques, capable of exploit key advantages of different

Abstract Continuous-bending-under-tension (CBT) has been conceived as a mechanical test or a forming process imparting cyclic bending during stretching of a metallic sheet or strip in order to increase its elongation to fracture (ETF) relative to simple tension (ST). In a recent work, over five times improved ETF by CBT over ST has been reported for a dual-phase (DP) steel DP 1180. This paper evaluates

Abstract To investigate the effects of forming parameters on the thermal rheological behavior and microstructure evolution of a 30CrMnSiNi2A ultra-strength steel during thermal plastic deformation, thermal compression tests were carried out under different forming temperatures and strain rates. The microstructure of 30CrMnSiNi2A steel suffered from thermal compression and rapid cooling was composed

Abstract Cold pilgering process is a seamless tube forming technology, in which the metal is subjected to a series of small incremental deformations. It has been extensively applied for the manufacturing of cladding tube in nuclear reactors, due to high dimensional accuracy and favorable texture evolution. Notwithstanding, the pilgered tubes showed a kind of shear cracks similar to those obtained during

Abstract Die swelling is one of the paramount factors that impresses dimensional accuracy and quality of functional parts in Fused Deposition Modeling (FDM), one of the most famous Additive Manufacturing (AM) processes. Die swelling is considered a critical phenomenon in polymer extrusion process affected by melt flow rate, extruder temperature and its geometry. In this research, the ABS melt polymer

The panel production of small batch sizes for the hull of large ships requires a stable and flexible forming process, which is momentarily manually controlled by a system operator. The manual forming press control includes the metal sheet handling above the forming tool for defining the contact point and engagement depth of the sword and subjective monitoring of the forming degree by using the light

Hydroforming is a relatively new metal forming process with many advantages over traditional cold forming processes including the ability to create more complicated components with fewer operations. For certain geometries, hydroforming technology permits the creation of parts that are lighter weight, have stiffer properties, are cheaper to produce and can be manufactured from fewer blanks which produces

The paper proposes a novel approach to model the in-plane resin flow in deformable thin-walled fiber preforms for liquid composite molding processes. By ignoring the through-thickness flow in large scale thin-walled components, the 3-D resin flow is simplified to an in-plane flow inside the preform by a specialized divergence theorem. Shell kinematics are used to describe the fiber preform deformation

The precise determination of the forming limit strains of a sheet metal is necessary in order to accurately predict the onset of failure in sheet metal forming processes. The method used to detect the onset of necking (i.e. the necking criterion) is a most important factor in formability analysis as it significantly affects the forming limit strains. Many different necking criteria have been developed

For affordable high-volume manufacture of sandwich panels with complex curvature and varying thickness, fabric skins and a core structure are simultaneously press-formed using a set of matched tools. A finite-element-based process simulation was developed, which takes into account shearing of the reinforcement skins, multi-axial deformation of the core structure, and friction at the interfaces. Meso-scale

Anisotropic composite cylinders and pressure vessels have been widely employed in automotive, aerospace, chemical and other engineering areas due to high strength/stiffness-to-weight ratio, exceptional corrosion resistance, and superb thermal performance. Pipes, fuel tanks, chemical containers, rocket motor cases and aircraft and ship elements are a few examples of structural application of fiber reinforced

Stringer sheet forming enables an efficient production of branched sheet metal structures. Compared to conventional sheet metal components, stringer sheets show a significant increase in stiffness and therefore offer new possibilities for lightweight design. A challenge in stringer sheet forming is the failure due to instability, which appears in the buckling of the stringer in concave curvatures.

In addition to strain hardening and residual stress, damage influences the product performance of forward rod extruded parts. Damage is usually neglected and difficult to quantify. The evolution of ductile damage in metal forming is closely correlated to the load path. An experimental approach using automated energy dispersive X-ray spectroscopy (EDX) particle analysis in scanning electron microscopy

This article describes the problems involved in modelling material cracking in skew rolling processes. The use of the popular damage criteria is impossible because of the lack of a calibration test that would make it possible to determine the critical value of material damage under conditions similar to those found in skew rolling. To fill this gap, a test called channel-die rotational compression

The majority of high-performance composite parts are nowadays designed using advanced numerical simulations that are able to accurately predict a part’s strength and deformation, providing that the internal ply architecture and exact fibre orientation are known with sufficient accuracy. However, most parts have some deviation of the fibre orientation from the ‘as-designed’ geometry, leading to the

Nowadays, the functional integration of workpieces challenges existing forming processes. The combination of established forming processes – like sheet metal and bulk forming – offers the possibility to counter this issue. The application of bulk forming operations on sheet metal semi-finished products, also called sheet-bulk metal forming (SBMF), is an innovative approach. The potential of SBMF cannot