Advances in Industrial and Manufacturing Engineering最新文献

The tensile test always delivers an in-depth understanding of true stress-strain relationship. However, it is not easy for the researchers to understand and evaluate the tensile properties of micro-specimens. This paper presents a research work aiming at the design and manufacturing of a small universal test machine (UTM) for measuring the mechanical properties of the miniaturised samples. The newly developed machine is sensitive to small loads and permits to obtain the stress-strain curves for thin materials. This portable UTM consists of a stepper motor, a load cell, a linear variable differential transformer (LVDT), a load cell amplifier and a data acquisition system. Copper based small and thin (50 μm) tensile test samples were tested on this machine at room temperature, and the calculated results were compared with the test results derived from a commercial UTM (METEX - 1 kN) to justify the validation of the developed apparatus. The obtained mechanical properties are in good agreement with the values obtained from a commercial UTM. To confirm the possibility of in-situ micro-observation, the surface roughness analysis has been conducted on the developed apparatus for pure copper foils under 3D laser-confocal microscope. Finally, it is concluded that this kind of testing apparatus could be manufactured within a manageable budget.

Additive manufacturing of ceramics stands to transform applications requiring wear resistance in severe environments (including high temperatures and pressures, harsh chemicals, and biomedical implants, among many other uses). However, applications in electromagnetics are gaining increased attention as newly-available materials like zirconia provide very low electromagnetic loss and also provide the highest permittivity possible in 3D printing with near full density. By 3D printing zirconia lattices, the density can be modulated spatially by varying strut and beam thicknesses at arbitrary positions (such as when following a spatial function). As the effective permittivity is related to the density, the speed of electromagnetic radiation (the speed of light, c) can be controlled in the 3D space. As a preliminary investigation to understand processing limits and mechanical performance, this effort has focused on evaluating the compression and flexural strength of both 3D printed solid and lattice structures with millimeter-scale unit cells post-processed with different conditions. Non-destructive computer tomography was included to identify and validate remediation of internal delamination with hot isostatic pressing. Although zirconia lattices fabricated with NanoParticle Jetting™ were relatively delicate, millimeter periodic features were possible and provided sufficient strength to maintain structural integrity for non-critical loading.

When sheets of aluminum alloys are pierced or trimmed, tool failure occurs by the transfer of material from the sheet to the surface of the tool. This phenomenon referred to as galling adversely affects sheared edge quality and increases energy consumption. An instrumented pneumatic press was designed and built to conduct shear–punch tests on 2 mm-thick AA5754-O sheets and to investigate the progression of galling to AISI M2 steel punching tools during dry and lubricated punching. The punching tests were performed using a clearance of 2.0% of the lower die diameter. Cumulative galling volumes were measured using a non-contact optical surface profilometer, and the rate of material transfer (the galling rate) was estimated for both dry and lubricated punching. The galling initially occurred at a high rate, and for dry punching, it was reduced to $74.6\times {10}^4\mu m^3/stroke$ between 20th and 125th strokes. Lubricating the aluminum sheet with an oil-based lubricant mitigated the material transfer, and the galling rate after the 20th stroke was reduced to $3.1\times {10}^4\mu m^3/stroke$. Punching force-displacement curves indicated a higher amount of energy expended to shear AA5754-O sheets in the dry punching compared to the lubricated punching that is suggested to be due to the higher galling resulting in higher friction forces at the interface.

In this work, aluminum matrix composite (AMC) was successfully fabricated by multi-pass friction stir processing (MPFSP) with nanoparticles SiC. A constant rotational tool speed of 1350, feed rate of 65 mm/min, tilt angle of 2° was used to enhance the microstructure and mechanical properties of multi-pass FSP/SiC of AA6082-T6. It can be observed that Nanoparticles SiC were fragmented totally and uniformly distributed in fifth pass FSP. Agglomeration of SiC decreases with increases in the number of passes. The ultimate tensile strength (UTS) of base metal AA6082 exhibited 215.54 MPa, and % strain of 24.91. After implementing multi-pass FSP with nanoparticles of SiC on the AA6082, the UTS was enhanced simultaneously as the FSP pass increases. The UTS of 1st pass, 2nd pass, 3rd pass, 4th pass, and 5th pass was observed as 223.61 MPa, 238.37 MPa, 255.63 MPa, 281.79 MPa and 296.86 MPa, respectively caused by strain-free fine grains during dynamic recrystallization (DRX) mechanism. In contrast, Vickers's hardness value along the centerline (stir zone) was observed as 89, 101, 119, 125, 133 HV with 1st pass, 2nd pass, 3rd pass, 4th pass, and 5th pass respectively.

The implementation of human-robot collaborative systems in industrial environments have widely extended during the last five years, from manufacturing applications reproduced in laboratory facilities or digital simulations to real automotive shop floors. Commonly, one way to guide their design has been through the adoption of international standards focused solely on the safe operation of collaborative robots. The main objective of this paper is the identification of basic components comprising human-robot collaborative systems design. This is supported by two steps, 1) Provide an extensive compendium of current applications and components within a varied set of manufacturing sectors and tasks. 2) Based on the latter, propose a selection of “structural components” for collaborative work. We conceptualized structural components as the organizational and technological alternatives necessary to fulfil the basic requirements and functionalities of human-robot collaborative systems. This document presents a systematic literature review that includes 50 exemplary case studies implemented in different manufacturing environments throughout the last five years praxis (2016–2020). Four structural components were identified in this paper: interaction levels, work roles, communication interfaces and safety control modes. Furthermore, it was found that physical contact-based collaboration for screwing assembly of small-sized parts and material handling of heavyweight objects are suitable applications for the automotive industry. Moreover, certified augmented and virtual reality devices were highlighted as convenient assistive technologies for safety and training manufacturing needs. The presented categorization will allow practitioners on selecting settings of compatible structural components that could respond better to trendy manufacturing requirements searching for highly personalized products.

The fourth industrial revolution comprises the digital transformation of manufacturing by means of an intensive integration of advanced information and communication technologies. The possibility of creating interactive virtual replicas of the physical entities to predict and detect physical issues and optimize processes is one of the key benefits of the manufacturing digitization. In the oil and gas industry, one of the essential activities that can take advantage of innovative digital technologies is the geometrical quality assurance of pipe spools. In this sense, this work focuses on the development of digital twins of pipe spools that embrace attributes of their physical counterparts to manage dimensional variation and to assist the geometrical quality assurance process. Based on data available in the design stage of the product realization loop, i.e., dimensional tolerance, it was possible to estimate the process capability and to predict, by sensitivity analysis, the behavior of the spool elements when assembling them to each other.

The aim of this paper is to analyze the relation between magnetic and mechanical properties during and after forming processes. For this purpose, several tensile tests were carried out on sheet metal samples up to a defined plastic strain. The specimens were left in the clamping device in order to relieve the force in several steps until the specimen was completely relieved. As a consequence, the gradual relief leads to a reduction of internal stress states. During the forming process, the initial magnetic relative permeability and magnetic anisotropy of the sample were measured several times. Both properties are related to the mechanical states in the material through the effects of magnetic embrittlement and magneto-elasticity. The plastic strain of the specimens was determined by optical measurements and the stresses in the measurement range during the tensile test was determined with the help of a subsequent numerical simulation. This made it possible for the first time to measure the magnetic properties of samples with different plastic strain and different stress states. The evaluation shows that there is a strong correlation between permeability and plastic strain as well as anisotropy and stress. Based on these findings, it has been confirmed, that the determination of the plastic strain by a soft sensor is possible.

The implementation of control systems in metal forming processes improves product quality and productivity. By controlling workpiece properties during the process, beneficial effects caused by forming can be exploited and integrated in the product design. The overall goal of this investigation is to produce tailored tubular parts with a defined locally graded microstructure by means of reverse flow forming. For this purpose, the proposed system aims to control both the desired geometry of the workpiece and additionally the formation of strain-induced α′-martensite content in the metastable austenitic stainless steel AISI 304 L. The paper introduces an overall control scheme, a geometry model for describing the process and changes in the dimensions of the workpiece, as well as a material model for the process-induced formation of martensite, providing equations based on empirical data. Moreover, measurement systems providing a closed feedback loop are presented, including a novel softsensor for in-situ measurements of the martensite content.

To produce cold-rolled steel strips with specific mechanical properties and surface roughness typically temper rolling is adopted. In most cases, a uniform roughness pattern on the strip surface is mandatory. Due to the wear of the textured work rolls, their surface roughness ($Ra$) continuously reduces during the process, which should be accounted for process control. However, conventional temper rolling systems fail to guarantee a uniform surface roughness. In this work, the influence of strip tension on the imprinting of surface roughness during temper rolling is analyzed based on a multi-scale FE modeling concept to explore new ways for surface roughness control. This is done in simulation where, a macroscopic rolling model incorporating strip tension is coupled to a mesoscopic imprinting model and both models are validated using copper rolling trials. The influence of different thickness reductions, strip tensions and incoming strip's surface roughness on imprinting is modeled and compared. The numerical results reveal that a higher strip tension decreases the roughness transfer, which presents potential to control the roughness transfer ratio without changing other process parameters like the prescribed thickness reduction in the future.