Mechanical Engineering

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be...

In the paper there is presented a dynamic model of the articulated shaft. The model is used for the analysis of critical angular velocities. This model can be rewritten into a computer program to handle rotating parts of gear pumps. Using the knowledge of the custom frequencies of the rotating parts one can prevent operational malfunctions of the pumps. The problems described in the contribution will serve as a basis for the formulation of critical speed of the gear pumps within the Program for Support of Applied Research and Experimental Development ALFA TA04010579 of the Technology Agency of the Czech Republic. Key words: articulated shaft, critical angular speed, geer pump

V článku je prezentován dynamický model kloubového hřídele, který je využíván pro analýzu kritických úhlových rychlostí. Tento model může být přepsán do počítačového programu, pro řešení rotujících částí zubových čerpadel. Využití znalosti vlastních frekvencí rotujících částí může zabránit provozním poruchám čerpadel.
Problematika popsaná v příspěvku bude sloužit jako východisko při formulaci modelu kritických otáček zubových čerpadel v rámci Programu na podporu aplikovaného výzkumu a experimentálního vývoje ALFA TA04010579 Technologické agentury České republiky.
Klíčová slova: kloubový hřídel, kritická úhlová rychlost, zubové čerpadlo

https://www.ijert.org/computer-aided-exhaust-valve-design-automation-using-creo-and-microsoft-excel-spreadsheet

https://www.ijert.org/research/computer-aided-exhaust-valve-design-automation-using-creo-and-microsoft-excel-spreadsheet-IJERTV9IS080211.pdf

3D Modeling has been widely used because of their ease in understanding, visualization, and generation of manufacturing drawing compared to 2D drafting. However modeling process is a time consuming and many draftsmen do not have the skills of performing such task. Exhaust valve is one of the component reputedly required nearly in all ic engines. It is the nose of the combustion engine to return exhaust gases out at a time of exhaust stroke. There are many tools and computer languages like C, C++, Python, Visual basic, Go language etc useful for task automation. In this paper we are automate the designing and solid modeling task of exhaust valve by creating graphical user tool to take input parameters required for exhaust valve design using visual basic programming language into the excel spreadsheet and integrate this spreadsheet with Creo or Pro-Engineering parametric tool for 3D solid modeling automation. To demonstrate our study we are considered to automate the exhaust valve design and solid model generation made by authors S.S Gawale & Dr S.N Shelke(8).

International standards highlight the steps required by risk assessment and involving first hazard identification, then risk evaluation and finally, if necessary, risk assessment. To check approach appropriateness to "risk evaluation" from manual patient handling through MAPO, a cross study was carried out in view of checking relationship between this new risk assessment model and occurrence of acute low back pain. After proper training the MAPO screening method was assessed in 31 wards, 411 exposed subjects of geriatric hospitals. At the same time health data were collected on occurrence of low back pain episodes during the last year both in the exposed subjects' group and the external reference group (n�237). Risk and clinical assessment data were tutored and checked by EPM research unit. The logistic analysis was used as a method to evaluate the relationship between risk index and acute low back pain. Investigating relationship between acute low back pain episodes a...

ABSTRACT Lean Six Sigma Executive Overview (Case Study) Templates are a guide to Lean Six Sigma Green Belt, Lean Six Sigma Black Belt, and Lean Six Sigma Master Black Belt Projects. Lean Six Sigma Practitioners use the DMAIC (Define, Measure, Analyze, Improve, and Control) Phases. The Lean Six Sigma Executive Overview (Case Study) include the most common tools used in the DMAIC Phases. There are Backup Slides that include the tools and templates of Optional or less often tools. There are guidelines in the notes section. These templates are used to document Lean Six Sigma Projects as they are executed. I wish you well on your projects. Steven Bonacorsi, Lean Six Sigma Master Black Belt.

Laser welding will be  an important welding process for different applications in aerospace , aircraft , automotive, electronics  and other industries, due to its capabilities like minimum heat affected zone, welding of various thicknesses, adoptability to welding of various materials possessing widely varying physical properties like melting point, absorption, reflectivity etc. It utilizes laser source as a non contact heat generation technology to weld different materials so as to achieve welds of high quality narrow width and high penetration depths without the need of filler wires. It may be necessary to understand the effect of process parameters on the weldability of materials for successful welding. Laser welding popularly uses two types of lasers like CO2 and Nd:YAG (neodymium doped yttrium – aluminium – garnet)  with different powers. Nd:YAG lasers are used to weld materials of different thicknesses involving powers upto 5 kW. Whereas, CO2 lasers are used for applications which involve higher powers upto 20 kW. Laser welding allows a direct transition from light energy into heat energy. This technique is involved with the process of laser - matter interaction in which various parameters such as pulse energy, pulse duration, spot size, welding speed, laser power, weld width, penetration depth, reflectivity, absorption coefficient, thermodynamic properties etc. are used for analysis. This paper presents a review of the different parameters including process as well as materials on the weldability of various materials like carbon steels, stainless steels, magnesium alloys, aluminium alloys, refractory materials such as vanadium, titanium, zirconium, tantalum etc. The selection of appropriate parameter for welding of specified material is discussed. The prominent weld defects common to the laser welding such as porosity, oxide inclusions, cracking, loss of alloying elements etc., are discussed as related to the microstructure as well as mechanical properties such as hardness, tensile strength and fatigue strength etc.

The aim of the present study was to examine an adapted integrated psycho-social model to predict sport injury rehabilitation adherence. A longitudinal prospective design was used whereby 70 patients attending private physiotherapy clinics completed a battery of questionnaires both pre- and post-rehabilitation treatment based on the adapted framework. All participants were receiving treatment for tendonitis-related injuries. Adherence was monitored prospectively over the entire rehabilitation program using an observational measure of clinic adherence, a self-report measure of home-based adherence, in addition to monitoring attendance at rehabilitation sessions. In the initial phase of rehabilitation learning goal orientation, attitudes and perceived severity were found to predict rehabilitation intention. Intentions were also found to mediate the relationship between the aforementioned variables and clinic rehabilitation. Self-efficacy and self-motivation were predictors of clinic rehabilitation and attendance but not home rehabilitation. During the maintenance phase of rehabilitation coping ability and social support were predictors regarding all three measures of adherence. Implications for practitioners rehabilitating injured athletes are discussed.

This project is modeled around reducing the overall drag and lift coefficient by modifying the geometry and comprehending the underlying rootphenomenon for the variation in these drag values. The designing of models used in this project is done through SOLIDWORKS, and CFD simulation in FLUENT (ANSYS) respectively. The purpose of this project is to reduce the inefficiency caused due to aerodynamic factors of drag, lift by presenting development, design and optimization of the geometry modifications of the base model. The improvement of aerodynamic behaviour around the periphery of the model is investigated through numerical simulation. The Ahmed Reference Body having 10 degree rear slant angle has been taken as benchmark model in this paper. Simulation of variants of multifarious modifications and examination of their results is performed to find the best suited variant form (dimension) to boost the aerodynamic efficiency of the model. CFD simulations on Ahmed Body were carried out in order to serve as a benchmark for validating all the simulation results. The steady-state simulations are based on the Reynolds averaged Navier-Stokes equations, with turbulence closure provided through two-equation k-epsilon realizable models.

Coordinate metrology is a field of metrology that is becoming increasingly popular in the manufacturing industry. Coordinate metrology enables the three-dimensional measurement to be carried out on complex object in a single setup. The instrument used for this purpose is known as the coordinate measuring machine or CMM. In general, the CMM comprises three frames that move along three orthogonal axes, i.e. X-, Y-and Z-axis. Usually, a contact device known as measuring probe is attached to the end of the Z-axis. The displacement along each axis is measured by a linear measurement system and the readings are sent to an electronic controller. The electronic controller is connected to a computer that also enables various types of data processing to be performed. Repeated measurements on similar objects can be done easily by programming the motion of the axes of the machine. This reduces the time taken for measurement and inspection up to 80% to 90%. These machines are made in various sizes and the methods of operation are based on either manual or computer-aided. 7.2. Types of CMM The basic CMM consists of three axes, each provided with a guide way that enable precise movement along a straight line. Each guide way has a carrier that moves along. The carrier enables the second carrier to move along a straight line based on the first guide way. Each axis is fitted with a precision scale that records the position of the carrier measured from a reference point. The measuring probe is fitted to the carrier on the third axis. When the measuring probe touches the object being measured, the measurement system records the position of all three axes. There are several physical configurations of CMMs. All the configurations have a method of moving the probe along three axes relative to the object. Although there are many designs of CMMs but they can be grouped into five basic types as follows: (a) Cantilever type, (b) Bridge type, (c) Horizontal arm type, (d) Column type and (e) Gantry type 7.2.1 Cantilever type CMM The schematic diagram of the cantilever type CMM is shown in Figure 6.1. In the cantilever type CMM the measuring probe it attached to the Z-axis and moves in the vertical direction. The Z-axis carrier is fitted to the cantilever arm and provides movement in the Y-direction. The Z-axis movement is provided by the table. This type of CMM design provides easy access to the work area and has high workspace volume.

The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1) general aerobic warm-up with static stretching, 2) general aerobic warm-up with dynamic stretching, 3) general and specific warm-up with static stretching and 4) general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested for movement time (kicking movement of leg over 0.5 m distance), countermovement jump height, sit and reach flexibility and 6 repetitions of 20 metre sprints. Results indicated that when a sport specific warm-up was included, there was an 0.94% improvement (p = 0.0013) in 20 meter sprint time with both the dynamic and static stretch groups. No such difference in sprint performance between dynamic and static stretch groups existed in the absence of the sport specific warm-up. The static stretch ...