Thursday, 7 November 2019

ABCD of Engineering Drawing

It is not possible to build a part that exactly planed but its fitment can match it. The engineering drawing is the controlling document that ensures the manufacturability of part. It creates with GD&T and controlled precisely so that machinists and quality engineers will use, print dimensions, and drawing notes to develop a manufacturing process and inspection methodology. It will construct high-precision components and matching the designer’s original vision.

Drawing is a graphical and GD&T is a symbolic language that communicates ideas and information from one engineer to another.

Levels of Design
Three levels of design are considered in engineering design, which are as follows:

System Design: Design of a system which fulfill the specific function and purpose.

Parameters Design: Mechanical parameters, electrical parameters, thermal parameters, quantity parameters designing... of a system.

Tolerance Design: Design for tolerances for fitment of assembly.

Specification and Tolerance
  • 10 ± 0.5: Specification is 10 and tolerance is 1.
  • Part to Part variation is control by Size tolerance
  • Within Part variation is control by Geometric Tolerance (Shape)
  • Size Tolerance > Geometric (Shape) Tolerance e.g. ±1 > ± 1/32 (0.03)

Tolerance: Allowance for specific variation

Size tolerance is independent tolerance while Geometric tolerance controlled by its Feature Control Frame (FCF).

14 GD&T characteristics in 5 categories = 14.5

1. FORM = (4)
1.     Flatness, 
2.     Straightness 
3.     Circularity 
4.     Cylindricity

1.     Perpendicularity 
2.     Parallelism  
3.     Angularity

3. LOCATION = (3) 
1.     Symmetry 
2.     Position
3.     Concentricity

4. RUNOUT = (2) 
1.     Circular run-out 
2.     Total run-out

5. PROFILE = (2) 
1.     Profile of a line
2.     Profile of a surface

8/4/2 Rule for Datums : 8Yes / 4No / 2Yes or No

(Orientation+Location +Runout) Form Profile

Symbols except for the Form tolerances (straightness, flatness, circularity and cylindricity) can use datums.

Basic Rules of Drawing
  • Dimensions are measured at 68°F (degree fahrenheit) or 20°C in mechanical engineering system design.
               (68°F − 32) × 5/9 = 20°C
  • MinimumMaximumBasicStroke and Reference dimensions never have any tolerances limit. These dimensions are free from tolerances.
  • Dimensions shall have only one interpretation in engineering drawing. It never gives you conflict in between the interpretation and understanding of drawing.
  • Reference dimensions should be kept as minimum value.
  • Centerlines and featurelines are at right angle and angle is not mentioned in drawing.
  • No zero allowed before decimal and digits must be equal after decimal in Inch unit system. For example; .12.25 and .50 . It should not be 0.12, 0.25 and .5 in this case.
  • Zero is must before decimal and no extra zero allowed after decimal in MM unit system. For example; 0.120.25 and 0.5 It should not be .12, .25 and .50
  • Primary datum control the Orientation of the feature in the drawing.
  • All associates dimensions are basic dimensions (tolerance free) in profile tolerance.

Monday, 5 February 2018

Tuesday, 29 August 2017

Engineering Materials Ductile Vs Brittle

Engineering Materials Ductile Vs Brittle
When you select the material for design, you must be very sure about functionality and applications of the product. There are different aspects that can affect the product such as Yielding, Toughness, Hardness, Thermal conductivity etc.

Ductile materials are those which can undergo plastic deformation under the tensile loading and it is the ability to be drawn into wire. Ductile materials are generally used in metal forming processes.

Brittle materials do not undergo any plastic deformation that's why they fracture if load exceed yielding value. Brittle material are harder then ductile materials. Glass, Ceramic, Gray Cast Iron are some of the brittle materials examples. Brittle has less energy absorbing capacity.

In Brittle materials fracture occur before yield point but ductile materials go beyond yield point. 

Wednesday, 10 May 2017

A hyperelastic or Green elastic Material

A hyperelastic or Green elastic Material
A hyper-elastic or Green elastic material is a type of constitutive model for ideally elastic material for which the stress-strain relationship derives from a strain energy density function. The hyperelastic material is a special case of a Cauchy elastic material.
Linear elastic models do not accurately describe the observed material behaviour for many materials. The most common example of this kind of material is rubber. The stress-strain relationship can be defined as non-linearly elastic, isotropic, incompressible and generally independent of strain rate for rubber. Hyperelasticity provides a means of modeling the stress-strain behavior of such materials. The uses of hyperelastic material are:

The behavior of unfilled, vulcanized elastomers often conforms closely to the hyperelastic ideal. Filled elastomers are also often modeled via the hyperelastic idealization.
Biological tissues are also modeled via the hyperelastic idealization and so on.

Sunday, 9 April 2017

Computer Aided Engineering (CAE) Market

Computer Aided Engineering (CAE) Market
Computer Aided Engineering (CAE) market can be segmented into Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA), and Multi-Body Dynamics (MBD) tools.

The market is also classified on the basis of end use into electronics and electrical, defense, aerospace, automobile, and industrial machinery.

The market segments on the basis of geographical regions are North America, Europe, Asia Pacific, South America, and Middle East and Africa (MEA). Asia Pacific is expected to lead the CAE market owing to the increasing adoption of CAE tools and the emergence of large number of manufacturing industries in the region.

Friday, 20 January 2017

Computer Aided Technology (CAT) or Simulation Technology

Computer Aided Technology (CAT) or Simulation Technology
Computer Aided Technology (CAT) or Simulation Technology is the discipline of designing a model of an actual or theoretical physical system, executing the model on a digital computer, and analyzing the execution output. To simulate something physical, you will first need to create a mathematical model which represents that physical object.

A computer simulation is a technique or technology to model a real-life or hypothetical situation on a computer so that it can be studied to see how the system works. You may be made predictions about the behavior of the system by changing variables in the simulation. It is a tool to virtually investigate the behavior of the system under study.

Manufacturing engineering represents one of the most important applications of simulation. This technique or technology represents a important tool used by engineers when evaluating the effect of failure, cost, and life of the equipment s. Simulation can be used to predict the performance of an existing or planned system and to compare alternative solutions for a particular design problem.

CAT or Simulation technology play major role in application engineering and it is a hot trend in the current IT market.  An applications engineer is responsible for designing and application of technology products relating to various aspects of computing. To accomplish this, he/she has to work collaboratively with the company’s manufacturing, marketing, sales, and customer service departments.

Sunday, 20 November 2016

Finite Element Analysis (FEA) Technology in Engineering

Finite Element Analysis (FEA) Technology in Engineering
I have been involved in engineering simulation for 10 years. In past during my collage days, when I was studying in engineering, a good part of my course looked at the fundamentals of structural analysis such as strength of material, mechanics of machine and so on. We had spent an enough amount of time manually calculating the deformation and stress results of a beam element and trusses problems. I had learned two major things from this exercise. FEA was incredibly useful for real world engineering problems. I could get an engineering answer to a reasonably realistic problem by using the FEA technology approach. FEA software is must if you want to do this on a more meaningful way. FEA technology gives you, answer to an engineering problem very faster and optimize than any other way. From engineering point of view, you always wary about-

What about if the hole is bigger or smaller in the design? What if I made it out of aluminum instead of steel, or if the load increased or decreed?

To get the answer about all these question, you need a model that can be setup to Finite Element Analysis. Once its set up, run the simulation to get answer each of these questions.

Even with the fastest solver available now a days to solve the problems, if it takes a long time to build a model then total time to getting results might be restrictive. But, if you able to set-up an FEA model efficiently and get from geometry to solution as fast as possible depends on everything in between. So, performance definitely relies on solver speed, but also on usability and productivity of the FEA software and engineer. The most common question and problem occur in FEA to determining the stress intensity factors of a load applied on a model. This can be in the form of a structure analysis, solid mechanic analysis, dynamics, thermal analysis, electrical analysis, bio-materials, etc. Generally, FEA technology is used to calculate the component displacements, strains, and stresses result under internal and external loads conditions applied on the model. Most of the FEA calculations involved metallic components and can be analyzed by either linear or nonlinear stress analysis. The selection of the linear or nonlinear analysis, depends upon the stiffness and loads on the design.

FEA calculations and simulations are done in CAE/FEA software like ANSYS, SIMULIA/Abaqus, SOLIDWORKS Simulation and so on. A model is designed in a CAD software like CATIA, Inventor, Creo, SOLIDWORKS and imported into CAE software to be analyzed. By using FEA technology, never have an exact answer or solution of an FEA problem. It gives us approximate solution of engineering problems.

FEA is an important part of the product design and development process. It identifies where problems may occur in a product or component. FEA mathematically calculates the problematic areas of a model, and reduce the time and efforts to create a physical prototype. You can not make modification in prototype testing, easily and it you do it again and again then will increase the cost of the test. Same time prototype testing does not provide the numerical information but FEA testing gives you all the numerical information about the product testing to make the product development process easy.

Tuesday, 20 September 2016

Finite Element Method(FEM)?

Finite Element Method(FEM)?
The Finite-Element Method(FEM) is a computational numerical solution method that divides a physical model or digital(CAD) model into very small but finite-sized elements of geometric shapes. The collection of all these shapes make a set that called finite-element mesh and the junction points of these shapes or elements called as node. In other words, mesh discretization take place in FEM. This is modeled by approximating the field conditions within each element as a simple function, such as a linear or quadratic polynomial, with a finite number of degrees of freedom (DOFs).

Alexander Hrennikoff (Russian; 1896 — December 31, 1984) was a Russian-Canadian Structural Engineer, and known as a founder of the Finite Element Method.

Richard Courant (January 8, 1888 – January 27, 1972) was a German American mathematician. R. Courant's name is also known for the finite element method, with his numerical solution of the plain torsion problem for multiply-connected domains, published a paper in 1943.

This method was first applied to structural analysis problems. Over the last ten years or so, it has been realized that the finite element method(FEM) is also suitable and fit for a large class of multi-physics problems. There are three mathematical ways or methods that FEM can use to evaluate the values at the nodes.

  • Non-variational method ( Ritz method)
  • Residual mehod (Galerkin ethod)
  • Variational method and(Rayleigh-Ritz method)
Finite Element Method is also known as Finite Element Analysis (FEA) and it is a technological application of FEM. You can not compute the solution of the equestions, created in the FEM. To solve these questions, you need to use computer adied technology which is FEA. FEA is applied in engineering as a computational tool for performing engineering analysis with the help of computer adied technology and use of software program coded with FEM algorithm. It includes the use of mesh generation techniques for dividing a complex field problem into small elements. The complex field problem is usually a physical system with the underlying physics such as the Euler-Bernoulli beam equation, the heat equation, or the Navier-Stokes equations expressed in either PDE or integral equations.