Strain distribution in severe plastic deformation of using equal channel angular pressing at 90° and 120° channel angles

Severe plastic deformation is capable of producing metals with ultra fine grained microstructure, and is the focus of this study. Equal channel angular pressing (ECAP) was used to perform severe plastic deformation on a Zn alloy. The process was simulated using finite element analysis for different channel angles of 90° and 120°. The input for material properties, loads, velocities, boundary conditions, and contacts were extracted from experiment and was assigned to the finite element models. The strain distribution values were obtained from the finite element analysis to determine how much effect the channel angle affects the Zn alloy sampl

Design and Development an Ergonomic Transfer Lifter Assistor From Wheelchair To Bed Transfer For Patients Under 50kg

Moving a patient from their bed to some other places for daily routine is such hard work. Caregiver usually using a wheelchair to move a patient from place to place. Nevertheless, they are facing a problem in lifting the patient from bed to wheelchair. The caregiver needs to use lots of energy to lift the patient into a wheelchair, and it may take a long time. This study focuses on design and develop a transfer lifter assistor to assist the caregiver move the patient from bed to another place. It was flexible and easy to conduct. This innovation's advantages are that the height could be adjusted, making the patient more comfortable to sit on from a bed. The size could be adjusted up to 3 and a half feet. The structure mostly from steel and can be disassembled for storage purposes. The result shows that Transfer Lifter Assistor can perform effectively to lift patients with a maximum weight of 50 kilograms. It can support one patient at a time. This innovation has been successfully produced with cost-effective and can be owned by everyone

Influence of Interface on epoxy/clay Nanocomposites: 1. Morphology Structure

AbstractA current challenge for the material scientists nowadays is the design and invention of new material systems that have a low weight, low cost but possess high levels of mechanical performance, good design flexibility and processability. This challenge has arisen due to the modern trend of utilizing lightweight and high performance materials, which has the potential to contribute to the advanced future applications, such as in aerospace, automotives, biotechnology, electronics and many more. In this new world, polymer nanocomposites have developed to be one of the latest evolutionary steps in the polymer technology, besides showing a great deal to become the most versatile industrial advanced materials. In comparison with conventional composites, nanocomposites demonstrate significantly higher levels of mechanical performance with less content of particles. The particle interface has been known to play a critical role in conventional composites. Nevertheless, the understanding of the role of interface in morphology polymer nanocomposites remains in its infancy. Thus, this study aims to develop a series of epoxy polymer layered-clay nanocomposites with levels of interface strength by designing chemical reactions or physical entanglements between nanoparticles and matrix polymer. In order to achieve this goal, three types of modifier were adopted: ethanolamine (denoted eth), Jeffamine M2070 (m27) and Jeffamine XTJ502 (xtj). The interface strength was identified through the morphology observation such as X-ray diffraction and scanning electron microscopy of fracture surface, in which later are correlated with various mechanical properties of nanocomposites

Determination of energy consumption during turning of hardened stainless steel using resultant cutting force

Downsizing energy consumption during the machining of metals is vital for sustainable manufacturing. As a prerequisite, energy consumption should be determined, through direct or indirect measurement. The manufacturing process of interest is the finish turning which has been explored to generate (near) net shapes, particularly for hardened steels. In this paper, we propose using measured cutting forces to calculate the electrical energy consumption during the finish turning process of metals where typically the depth of cut is lower than the cutting tool nose radius. In this approach, the resultant cutting force should be used for calculating the energy consumption, instead of only the main (tangential) cutting force as used in the conventional approach. A case study was carried out where a hardened stainless steel (AISI 420, hardness of 47–48 HRC) was turned using a coated carbide tool, with a nose radius of 0.8 mm, without cutting fluid, and at 0.4 mm depth of cut. The experimental design varied the cutting speed (100, 130, and 170 m/min) and feed (0.10, 0.125, and 0.16 mm) while other parameters were kept constant. The results indicate that the electrical energy consumption during the particular dry turning of hardened steel can be calculated using cutting force data as proposed. This generally means machining studies that measure cutting forces can also present energy consumption during the finish or hard turning of metals, without specifically measuring the power consumption of the machining process. For this particular dry turning of hardened stainless steel, cutting parameters optimization in terms of machining responses (i.e., low surface roughness, long tool life, low cutting force, and low energy consumption) was also determined to provide an insight on how energy consumption can be integrated with other machining responses towards sustainable machining process of metals

Improvement in mechanical properties of ijuk fiber composite by using silane treatment

The rising concern towards environmental issues besides the need for more versatile polymer-based materials has led to increased interest in studying polymer composites filled with natural-fibers, usually referred to as “green” composites. However, the bonds between polymeric materials are not strong enough by referring to mechanical properties and other additional properties due to incompatibility between the polymer matrix and natural fiber filler. Thhis study tries to improveme the mechanical properties of Ijuk (Arenga pinnata) fiber filled polypropylene composite by using silane treatment. Vinyltrimethoxy silane was used for this purpose. The ijuk fiber was immersed in the silane solution before mixing with polypropylene at 10wt%, 20wt%, and 30wt%. The samples were tensile tested and their water absorption behavior was test as well. As the result, the treatment helps increasing the mechanical properties of the green composite material and decreases the percentage of water absorptio

Finite element analysis of mini implant biomechanics on peri-implant bone

Mini dental implant whose diameter is between 1.8 and 2.4 mm is a dental implant design currently implemented as bone screw in in orthodontics, as support for denture, and in situations when smaller diameter implant is the feasible option. Biomechanics of the peri-implant bone inserted by mini dental implant is of interest in this study where relevant studies are lacking. This study was intended to investigate using finite element analysis the induced stress and strain on peri-implant bone when a mini dental implant is loaded. The thread pitch of the mini dental implant and the peri-implant bone type were varied, with a constant loading (100 MPa pressure) applied on the mini implant. First, the mini dental implant with three different thread pitches (0.5 mm, 1.0 mm and 1.5 mm) were inserted into a type II bone. It was found that the higher the thread pitch, the higher the maximum stress (increased from 53.2 to 78.6 MPa) and the less distributed the stress on the peri-implant bone. Next is a mini dental implant with 1.0 mm thread pitch was inserted into peri-implant bone types II, III and IV. When the bone type changes from II to III, the maximum stress becomes lower (from 57.8 to be 51.7 MPa) but more high stress was distributed in the cortical bone. The strain was more than doubled (from 0.82 to be 1.76%) on the cancellous bone. When the bone type changes from III to IV, the maximum stress was doubled (from 51.7 to be 104.8 MPa) and more high stress was distributed over the cortical bone. In cancellous bone, the maximum stress was lower (from 9.1 to be 5.3 MPa), but the strain increases almost three folds (from 1.76 to be 5.07%)

Hybrid experimental-computational approach for solder/IMC interface shear strength determination in tin-lead solder joints

Damage-based models for solder/intermetallics (IMC) interface often require the interface properties such as tensile and shear strengths. The minute size of the solder joint renders direct experimental determination of these properties impractical. This paper presents a hybrid experimental-computational approach to determine the shear strength of solder/IMC interface. Displacement-controlled ball shear tests are performed on as-reflowed and thermally-aged solder specimens. The observed sudden load drop in the load-displacement curve corresponds to the crack initiation event and the load is indicative of the shear strength of the solder/IMC interface. Finite element simulation of the ball shear test is then employed to establish the complex stress states at the interface corresponding to the onset of fracture. The finite element model consists of Sn40Pb solder, Ni3Sn4 intermetallic and Ni layers, copper pad and a rigid shear tool. Unified inelastic strain theory describes the strain rate-dependent response of the solder while other materials are assumed to behave elastically. Quasi-static ball shear test is simulated at 30°C with a prescribed displacement rate of 0.5mm/min. Results show that steep stress gradients develop in the shear tool-solder contact and solder/IMC interface regions indicating effective load transfer to the interface. The bending (normal) stress is found to be of the same order of magnitude as the maximum shear stress. Higher stress values are predicted near the leading edge of the solder/IMC interface. The equivalent shear stress condition to the triaxial stress state at the interface, represented by the absolute maximum shear stress, τmax,abs should have reached the shear strength of the interface at fracture. The resulting shear strength of Sn40Pb/Ni3Sn4 interface is determined to be 87.5 MPa

Polycaprolactone-starch blends with corn-based coupling agent: physical properties and in vitro analysis

In an attempt to improve properties of polycaprolcatone-starch blend, this study uses zein as coupling agent in preparing the blend through a single-step process. Zein, which has affinity to both polar and non-polar groups, is expected to improve miscibility between the blends' constituents and its overall biocompatibility. Mechanical properties of the blend were tested and further characterizations (Fourier transform infrared spectroscopy, thermal properties) were performed to analyze the effect of zein as an addition to the blend's physical properties. The blend's biocompatibility was examined by indirect methods (contact angle and weight gain after immersion in simulated body fluid) and in vitro analysis. No significant effect on the blend's strength and stiffness was caused by adding zein. Hydrophilicity and cell affinity were improved when zein was added. Zein did not perform as a coupling agent that improved miscibility between polycaprolactone and starch, but its addition improved the blend's biocompatibility

The Effect of Squeeze Casting Process on Mechanical and Micro-structural Properties of Magnesium AZ31

The amount of damage that occurs in various cases of fractures in the bone, both accidents and other events is increasing, it is necessary to have materials which are natural or artificial that can interact with the body system with the aim of repairing, restoring and replacing damaged tissue or as a network connector. body. The use of magnesium as a biodegradable stent material is also based on a fixed tissue structure which is an important element in the body's organs, magnesium is also considered a non-carcinogenic element. The results of the implantation of the stent material that the mechanical properties of the material can survive during the implantation process without showing failure. The parameters used in this research, The sample used is a material that has been squeezed through the squeeze casting process with each pressure variation of 250 MPa, 350 MPa, 500 MPa and 550 MPa at a temperature of 4000C for a pressing time of 1 minute, with a holding time of 5 minutes and argon gas pressure of 1 bar. . In this study it can be concluded that the variation of pressure greatly affects the results of the level of hardness. In this test, it can be seen that the higher the pressure, the greater the hardness value. The highest value is found at a pressure of 550 MPa at 51 HRV, and the highest maximum stress value is 128.26 MPa, this value is close to the tensile strength of the mechanical properties of the cortical and concelues bone. with a holding time of 5 minutes and argon gas pressure of 1 bar. In this study it can be concluded that the variation of pressure greatly affects the results of the level of hardness. In this test, it can be seen that the higher the pressure, the greater the hardness value. The highest value is found at a pressure of 550 MPa at 51 HRV, and the highest maximum stress value is 128.26 MPa, this value is close to the tensile strength of the mechanical properties of the cortical and concelues bone. with a holding time of 5 minutes and argon gas pressure of 1 bar. In this study it can be concluded that the variation of pressure greatly affects the results of the level of hardness. In this test, it can be seen that the higher the pressure, the greater the hardness value. The highest value is found at a pressure of 550 MPa at 51 HRV, and the highest maximum stress value is 128.26 MPa, this value is close to the tensile strength of the mechanical properties of the cortical and concelues bone