Posted tagged ‘proof’

Prototype Advantages and Disadvantages

September 25, 2011

Rapid prototype is a process wherein a working model or prototype is developed for the purpose of testing the various product features like design, ideas, features, functionality, performance and output. This process of development of working model is quite quick. The user can give an early feedback regarding the prototype. Rapid prototyping is, generally, a significant and essential part of the system designing process and it is believed to decrease the project cost and risk.

01prototypesmithparadisebirdburlesque

The Rapid prototype that is developed by the process of rapid prototyping is based on the performance of earlier designs. Hence, it is possible to correct the defects or problems in the design by taking corrective measures. The product can be produced if the prototype meets the requirements of all designing objectives after sufficient refinement. There are many advantages of rapid prototyping.

ADVANTAGES:

  • Rapid Prototyping can provide with concept proof that would be required for attracting funds.

  • The Prototype gives the user a fair idea about the final look of the product.

  • Rapid prototyping can enhance the early visibility.

  • It is easier to find the design flaws in the early developmental stages.

  • Active participation among the users and producer is encouraged by rapid prototyping.

  • As the development costs are reduced, Rapid prototyping proves to be cost effective.

  • The user can get a higher output.

  • The deficiencies in the earlier prototypes can be detected and rectified in time.
  • The speed of system development is increased. It is possible to get immediate feedback from the user.

  • There is better communication between the user and designer as the requirements and expectations are expressed in the beginning itself.

  • High quality product is easily delivered by way of Rapid prototyping.

  • Rapid prototyping enables development time and costs.

  • There are many innovative ways in which Rapid prototyping can be used.

DISADVANTAGES:

  • Some people are of the opinion that rapid prototyping is not effective because, in actual, it fails in replication of the real product or system.

  • It could so happen that some important developmental steps could be omitted to get a quick and cheap working model. This can be one of the greatest disadvantages of rapid prototyping.

  • Another disadvantage of rapid prototyping is one in which many problems are overlooked resulting in endless rectifications and revisions.

  • One more disadvantage of rapid prototyping is that it may not be suitable for large sized applications.

  • The user may have very high expectations about the prototype’s performance and the designer is unable to deliver these.

  • The system could be left unfinished due to various reasons or the system may be implemented before it is completely ready.

  • The producer may produce an inadequate system that is unable to meet the overall demands of the organization.

  • Too much involvement of the user might hamper the optimization of the program.

  • The producer may be too attached to the program of rapid prototyping, thus it may lead to legal involvement.

  • The cost reduction benefit of rapid prototyping also seems to be debatable, as sufficient details regarding the calculation basis and assumptions are not substantial.

02PrototypeDisadvantages

Red Marbles, Blue Marbles

August 24, 2011

Problem: you have two jars, 50 red marbles, 50 blue marbles. you need to place all the marbles into the jars such that when you blindly pick one marble out of one jar, you maximize the chances that it will be red. (when picking, you’ll first randomly pick a jar, and then randomly pick a marble out of that jar) you can arrange the marbles however you like, but each marble must be in a jar.

Solution

Chance! chance is easy if you know how to do the formula. we know that we have two choices to make. first we’ll pick a jar, and each jar will have a 1/2 chance of being picked. then we’ll pick a marble, and depending how we stack the marbles, we’ll have a (# of red marbles in jar)/(# of total marbles in jar) chance of getting a red one.

for example, say we put all the red marbles into JAR A and all the blue ones into JAR B. then our chances for picking a red one are:

1/2 chance we pick JAR A * 50/50 chance we pick a red marble
1/2 chance we pick JAR B * 0/50 chance we pick a red marble

do the math and you get 1/2 chance for a red marble from JAR A and a 0/2 chance for a red marble from JAR B. add ‘em up and you get the result = 1/2 chance for picking a red marble.

think about it for awhile and see if you can figure out the right combination. we had a 50/50 (guaranteed) chance in picking a red marble from JAR A, but we didn’t have to have 50 red marbles in there to guarantee those fantastic odds, did we? we could’ve just left 1 red marble in there and the odds are still 1/1. then we can take all those other marbles and throw them in JAR B to help the odds out there.

let’s look at those chances:

1/2 we pick JAR A * 1/1 we pick a red marble
1/2 we pick JAR B * 49/99 we pick a red marble

do the math and add them up to get 1/2 + 49/198 = 148/198, which is almost 3/4.

we can prove these are the best odds in a somewhat non-formal way as follows. our goal is to maximize the odds of picking a red marble. therefore we can subdivide this goal into maximizing the odds of picking a red marble in JAR A and maximizing the odds of picking a red marble in JAR B. if we do that, then we will have achieved our goal. it is true that by placing more red marbles into a jar we will increase the chances of picking a red marble. it is also true that by reducing the number of blue marbles in a jar we will increase the odds also. we’ve maximized the odds in JAR A since 1/1 is the maximum odds by reducing the number of blue marbles to 0 (the minimum). we’ve also maximized the number of red marbles in JAR B. if we added any more red marbles to JAR B we would have to take them out of JAR A which reduce the odds there to 0 (very bad). if we took any more blue ones out of JAR B we would have to put them inJAR A which reduce the odds there by 50% (very bad).

it wasn’t really a good proof, but QED anyway 😛

MECHANICAL TESTING

August 23, 2011

Various tests:

  • Tensile Test

A tensile test, also known as a tension test, tests a material’s strength. It’s a mechanical test where a pulling force is applied to a material from both sides until the sample changes its shape or breaks. It’s is a common and important test that provides a variety of information about the material being tested, including the elongation, yield point, tensile strength, and ultimate strength of the material. Tensile tests are commonly performed on substances such as metals, plastics, wood, and ceramics.

01-Electronic_Tensile_Testing_Machine-calculate tensile strength-yield strength-ultimate strength-break value-elongation-testing steels, iron, plastics and composite materials

Tensile testing systems use a number of different units of measurement. The International System of Units, or SI, recommends the use of either Pascals (Pa) or Newtons per square meter (N/m²) for describing tensile strength. In the United States, many engineers measure tensile strength in kilo-pound per square inch (KSI).

01-TensileStrength-tensile test-Calculate Ultimate tensile strength-tensile property testing of plastics, steel, iron-material strength calculate - pascals - newton per square meter

  • Tensile test with electronic extensometer

01-electronic_extensometer-calculate proof stress - youngs modulus values-material stress-acccepts load-extension value

This instrument is to be used on Tensile or Universal testing machines to find out Proof stress & Young’s modulus values. In case of many brittle materials such as high carbon steels, alloy steels, light aluminium & magnesium alloys, it is difficult to get yield values. For such materials stress corresponding to a certain allowable amount of plastic deformation is termed as proof stress say 0.1% or 0.2% proof stress. The measuring range is up to 5mm & resolution is 0.001mm.

01-mechanical_extensometer-tensile test calculation-universal testing machine-utm

  • Tensile testing at elevated temperature.

01-tensile test at elevated temperature-high temperature tensile test-specialist tensile test

High temperature tensile testing is a procedure to test the properties of a material at above room temperature. It will determine the following parameters:

  • Tensile strength (breaking strength)
  • Yield strength
  • Elongation
  • Reduction of area

Specialist testing, measurement and control equipment is required to perform this test.
The results of such a test will provide a good indication of the static load bearing capacity of the material and therefore establishes the suitability of a material for its intended purpose.

  • Tensile test on Tor steel Bars

01-tor-steel-bar-rods-TMT steel Bars-concrete technology-durable-corrosion resistant-engineering and construction

TOR steel is one of the best grade of steel used in concrete reinforced. It’s a kind of high adherence steel. Other types of steel are used for less resistance concrete. Thermo mechanically Treated (TMT) bars are a type of corrosion resistant steel reinforcing bar used in concrete construction.

  • Bend test on plates

01-bend test on steels- cold bars -cold bend testing for steels

A bend test is used to determine whether a specific piece of metal in question will break or fracture under pressure. This is important in the construction of any project using metal, otherwise the building or the item being made could collapse from the immense pressure exerted on it. Every piece of metal made cannot be tested, therefore certain pieces are tested and if they pass, the other pieces are made using the same process. The results of a bend test are reported differently depending on the type of material tested. There is no standard method for reporting the durability that applies to all materials, rather each group has its own set by which it is judged and compared to other metals in that group.

The bend test is essentially measuring a metal’s ductility. Ductility defines how easily a metal can bend without breaking. The higher the ductility of a metal, the more it can bend without breaking or becoming deformed from its original shape. This is important because certain metals must handle pressure without snapping yet still be ductile enough to bend slightly and not lose their support or shape. Copper and steel are two metals that have a high ductility and do well under pressure.

  • Bend test on pipes

01-bend test on pipes

Bending tests are carried out to ensure that a metal has sufficient ductility to stand bending without fracturing. A standard specimen is bent through a specified arc and in the case of strip, the direction of grain flow is noted and whether the bend is with or across the grain.

  • Bend Test on Tor steel

01-wire-rods-rebend test on steels

The purpose is to make certain the weld and the base metal are properly fused, and that the weld metal and the heat affected zone (HAZ) have appropriate mechanical properties

  • Re-Bend test on Tor steel

01-wire-rods-rebend test on steels

The purpose of re-bend test is to measure the effect of strain ageing on steel. Strain ageing has embrittlement effect which takes place after cold deformation by diffusion of nitrogen in steel. Hence, there is limitation stated in some design codes to restrict the nitrogen content of steel to 0.012%.

  • Nick Break Test

01-nick break test-welding-fabrication-on sheets

The NICK-BREAK TEST is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions,  gas  pockets,  lack of  fusion,  and  oxidized  or burned metal. To accomplish the nick-break test for checking a butt weld, you must first flame-cut the test specimens from a sample weld.

MECHANICAL TESTING

August 23, 2011

Various tests:

  • Tensile Test

A tensile test, also known as a tension test, tests a material’s strength. It’s a mechanical test where a pulling force is applied to a material from both sides until the sample changes its shape or breaks. It’s is a common and important test that provides a variety of information about the material being tested, including the elongation, yield point, tensile strength, and ultimate strength of the material. Tensile tests are commonly performed on substances such as metals, plastics, wood, and ceramics.

01-Electronic_Tensile_Testing_Machine-calculate tensile strength-yield strength-ultimate strength-break value-elongation-testing steels, iron, plastics and composite materials

Tensile testing systems use a number of different units of measurement. The International System of Units, or SI, recommends the use of either Pascals (Pa) or Newtons per square meter (N/m²) for describing tensile strength. In the United States, many engineers measure tensile strength in kilo-pound per square inch (KSI).

01-TensileStrength-tensile test-Calculate Ultimate tensile strength-tensile property testing of plastics, steel, iron-material strength calculate - pascals - newton per square meter

  • Tensile test with electronic extensometer

01-electronic_extensometer-calculate proof stress - youngs modulus values-material stress-acccepts load-extension value

This instrument is to be used on Tensile or Universal testing machines to find out Proof stress & Young’s modulus values. In case of many brittle materials such as high carbon steels, alloy steels, light aluminium & magnesium alloys, it is difficult to get yield values. For such materials stress corresponding to a certain allowable amount of plastic deformation is termed as proof stress say 0.1% or 0.2% proof stress. The measuring range is up to 5mm & resolution is 0.001mm.

01-mechanical_extensometer-tensile test calculation-universal testing machine-utm

  • Tensile testing at elevated temperature.

01-tensile test at elevated temperature-high temperature tensile test-specialist tensile test

High temperature tensile testing is a procedure to test the properties of a material at above room temperature. It will determine the following parameters:

  • Tensile strength (breaking strength)
  • Yield strength
  • Elongation
  • Reduction of area

Specialist testing, measurement and control equipment is required to perform this test.
The results of such a test will provide a good indication of the static load bearing capacity of the material and therefore establishes the suitability of a material for its intended purpose.

  • Tensile test on Tor steel Bars

01-tor-steel-bar-rods-TMT steel Bars-concrete technology-durable-corrosion resistant-engineering and construction

TOR steel is one of the best grade of steel used in concrete reinforced. It’s a kind of high adherence steel. Other types of steel are used for less resistance concrete. Thermo mechanically Treated (TMT) bars are a type of corrosion resistant steel reinforcing bar used in concrete construction.

  • Bend test on plates

01-bend test on steels- cold bars -cold bend testing for steels

A bend test is used to determine whether a specific piece of metal in question will break or fracture under pressure. This is important in the construction of any project using metal, otherwise the building or the item being made could collapse from the immense pressure exerted on it. Every piece of metal made cannot be tested, therefore certain pieces are tested and if they pass, the other pieces are made using the same process. The results of a bend test are reported differently depending on the type of material tested. There is no standard method for reporting the durability that applies to all materials, rather each group has its own set by which it is judged and compared to other metals in that group.

The bend test is essentially measuring a metal’s ductility. Ductility defines how easily a metal can bend without breaking. The higher the ductility of a metal, the more it can bend without breaking or becoming deformed from its original shape. This is important because certain metals must handle pressure without snapping yet still be ductile enough to bend slightly and not lose their support or shape. Copper and steel are two metals that have a high ductility and do well under pressure.

  • Bend test on pipes

01-bend test on pipes

Bending tests are carried out to ensure that a metal has sufficient ductility to stand bending without fracturing. A standard specimen is bent through a specified arc and in the case of strip, the direction of grain flow is noted and whether the bend is with or across the grain.

  • Bend Test on Tor steel

01-wire-rods-rebend test on steels

The purpose is to make certain the weld and the base metal are properly fused, and that the weld metal and the heat affected zone (HAZ) have appropriate mechanical properties

  • Re-Bend test on Tor steel

01-wire-rods-rebend test on steels

The purpose of re-bend test is to measure the effect of strain ageing on steel. Strain ageing has embrittlement effect which takes place after cold deformation by diffusion of nitrogen in steel. Hence, there is limitation stated in some design codes to restrict the nitrogen content of steel to 0.012%.

  • Nick Break Test

01-nick break test-welding-fabrication-on sheets

The NICK-BREAK TEST is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions,  gas  pockets,  lack of  fusion,  and  oxidized  or burned metal. To accomplish the nick-break test for checking a butt weld, you must first flame-cut the test specimens from a sample weld.