Machine Design 1 Reviewer (Simple Stress) PDF

Summary

This document provides an overview of simple stress concepts within machine design. It covers topics such as ultimate stress, yield point, elastic limit, and proportional limit. The document also includes information on various properties of materials, such as alloying elements and their effects on the material.

Full Transcript

MACHINE DESIGN 1 Alloying Elements Free Carbon REVIEWER (SIMPLE STRESS) - usually considered to be the - Part of the carbon content of metallic ele...

MACHINE DESIGN 1 Alloying Elements Free Carbon REVIEWER (SIMPLE STRESS) - usually considered to be the - Part of the carbon content of metallic elements added for steel or iron that is in the the purpose of modifying form of graphite or temper Ultimate Stress / Tensile Strength the properties carbon - The highest point on the Anisotropy Hard Drawn stress-strain curve, is the maximum load divided by - exhibiting different - temper produced in a wire, the original area before properties when tested in rod, or tube by cold straining occurs different directions. drawing. Yield Point Brittleness Homogeneous Material - stress at which a low or - The tendency to fracture - having the same structure at medium-carbon steel without appreciable all points undergoes a marked deformation. elongation without an Isotropic Material increase in load Charpy Test - materials having the same Yield Strength - supported at both ends as a properties in all directions. simple beam, it is broken by - the stress for a specified the impact of a falling Izod Test deviation from the straight pendulum - test in which a specimen is part of the stress-strain supported at one end as a curve Cold Shortness cantilever beam and broken Elastic Limit - the brittleness of metals at by the impact of a falling ordinary or low pendulum. - Maximum stress that a temperature. material will withstand Killed Steel without permanent Cold Working - steel that has been deformation. - the process of deforming a deoxidized with a strong Proportional Limit metal plastically at a deoxidizing agent such as temperature below that at silicon in order to eliminate - the stress at which the which it recrystallizes to a reaction between the stress-strain curve deviates produce strain-hardening carbon and oxygen during solidification Modulus of Elasticity (E) Damping Capacity Machinability - the proportionality constant - the ability of a material to in tension; it is a measure of absorb vibrations. - indefinite property that stiffness refers to the relative ease Decarburization with which a material can Section Modulus be cut. - loss of carbon from the - The ratio I/C surface of steel, occurring Malleability during hot rolling and heat Modulus of Elasticity in Shear treatment - material's susceptibility to - also called modulus of extreme deformation in Ductility rolling or hammering; the rigidity and transverse modulus - property that permits ability of a substance to be permanent deformation hammered or beaten into Design Stress before fraction in tension thin sheets - also called safe stress, Elasticity Mechanical Properties working stress, and allowable stress; stress that - ability of a metal to be - those that have to do with is computed so that failure deformed and to return to its stress and strain; ultimate will not occur original shape strength and percent elongation Alloy Embrittlement Percent Elongation - composed of two or more - loss of ductility because of a elements of which at least physical or chemical change one is metal of the material. ria dela cruz | bsme 4-1 | plm - the extension in the vicinity permit one or more - heating of certain steels of the fracture of a tensile constituent to pass into solid above the transformation specimen solution range and then quenching, for the purpose of Percentage Reduction of Area Stiffness increasing the hardness - the smallest area at the point - the ability to resist Malleablizing of rupture of a tensile deformation specimen divided by the - annealing process whereby original area Temper combine carbon in white - a condition produced in a cast iron is transformed Physical Properties wholly or in part to temper non-ferrous metal by - properties such as density, mechanical or thermal carbon conductivity, coefficient of treatment Spheroidizing thermal expansion Toughness - heating or cooling of steel Plasticity produces a rounded or - capacity of material to - ability of a metal to be withstand a shock load globular form of carbide deformed considerably without breaking Stress Relieving without rupture Transverse Strength - heating of a metal body to a Poisson's Ratio suitable temperature and - refers to the results of a - the ratio of the lateral strain transverse bend test; also holding it at that (contraction) to the called rupture modulus temperature for a suitable longitudinal strain time for the purpose of (extension) Heat Treatment reducing internal residual stress Precipitation Heat Treatment - operations involving the heating and cooling of metal Tempering - brings about the or an alloy in the solid state precipitation of a constituent for the purpose of altering - reheating of hardened or from a supersaturated solid the properties of the metal normalized steel to a solution by holding the temperature below the body at an elevated Aging / Age Hardening transformation range, temperature also called followed by any desired rate - change in a metal by which artificial aging.Pro of cooling its structure recovers from Proof Stress an unstable or metastable Transformation Range condition that has been - Stress that causes a produced by quenching or - the temperature interval specified permanent cold working during which austenite is deformation of a material, formed during heating; it is usually 0.01% or less. Annealing also the temperature interval during which austenite Red Shortness - heating and slow cooling of disappears during cooling a solid metal, usually done - brittleness in steel when it is to soften it Hardness red hot Critical Range - a measure of a materials Relaxation resistance of indentation - has the same meaning as - associated with creep, is the transformation range Brinnel Hardness Number decreasing stress at constant strain Drawing - determined by a standard pressure applied to a 10-mm Residual Stress - often used to mean ball which is pressed for 10 tempering sec or more on the surface - stress not due to applied Graphitizing of the material being tested loads or temperature gradients - causes the combined carbon Rockwell Tester Solution Heat Treatment to transform wholly or in - measures the depth of the part into graphitic or free penetration by the indenter - The process of holding an carbon alloy at a suitably high Vickers Tester temperature long enough to Hardening ria dela cruz | bsme 4-1 | plm - has a square-base, diamond - is used for deoxidation and nitrogenous environment, pyramid indenter for stabilizing austenitic commonly ammonia gas, at stainless steels; it increases temperatures much lower Vickers Number the hardness and strength at than those used in the - the load in kilograms high temperature previously described divided by the impressed process Vanadium (V) area in square millimeters Carbonitriding - promotes fine-grain Shore Scleroscope Number structure, improves the ratio - a process of case hardening - obtained by letting a freely of endurance strength to steel by the simultaneous falling hammer with a ultimate strength of absorption of carbon and diamond point strike the medium-carbon steels nitrogen from a surrounding object to be tested and hot gaseous atmosphere, Hardenability followed by either measuring the height of rebound - capacity of steel to through- quenching or slow cooling harden when cooled from Flame Hardening ASTM above its transformation - American Society for range - a process of heating the Testing and Materials surface of an iron-base Case Hardening alloy, which is preferably SAE - a process of surface annealed or normalized, and hardening whereby the then quenching it - Society of Automotive Engineers surface or case is Work Hardening substantially harder than the AISI core or inside metal - the result of a metal being stressed at some point into - American Iron and Steel Carburizing its plastic range Institute - a process of adding carbon Wrought Iron Nickel (Ni) to the surface of steel by exposing it to hot - made by burning the carbon - strengthens unquenched and carbonaceous solids, from molten iron and then annealed steels, toughens liquids, or gases-above the putting the product through steel, and simplifies heat transformation temperature hammering and rolling treatment by lessening operations distortion Gas Carburizing Cast Iron Phosphorus (P) - the part is heated in carburizing gases, such as - includes white cast iron, - increases hardenability, methane, ethane, propane malleable iron, and nodular strengthens low-carbon and CO cast iron steels, improves machinability of free- Liquid Carburizing Gray Iron cutting steels, and improves resistance to corrosion - the part is immersed in a - has excellent wearing molten salt bath that imparts properties that are improved Selenium (Se) a case similar to that by certain alloys and by heat obtained with gas or pack treatment - improves machinability of carburizing except that the stainless steel; also added to White Cast Iron case in thinner, usually not leaded resulfurized carbon in excess of about 0.025 in. - most of the carbon is steels for the same purpose. Cyaniding combined chemically with Silicone (Si) the iron and as a result the - is accomplished by metal is very hard - strengthens low-alloy steel immersing the part in a hot and improves resistance to Chilled Iron liquid salt bath, sodium high oxidation cyanide (NaCN) being a - produced by using an iron Tantalum (Ta) common medium plate in the mold to cause Nitriding rapid cooling of the surface - is a stabilizer - the machined and heat- Malleable Iron Titanium (Ti) treated part is placed in a ria dela cruz | bsme 4-1 | plm - is heat-treated white cast Thermoplastic machine shaft iron. - plastic that softens as the - Those forming an integral Nodular Cast Iron temperature rises and part of machine itself. remains soft in the heated - also called ductile iron, has state Splines the castability, machinability, and Thermosetting - Permanent keys made wearability of gray iron, but integral with the shaft and higher in strength and - plastic that undergoes fitting into keyways ductility chemical change and broached into the mating hardens when heated, hub. It is recommended Cast Steel usually under pressure when the power transmitted is too high that three keys - combination of highest Phenolics are not enough, strength and highest ductility in cast ferrous - they are made from Shafting metal is obtained formaldehyde and phenolic bodies such as phenols, - Cylindrical machine used to Stainless Steel cresols or cresylic acid transmit rotary motion and power from a driver to a - relatively expensive, but Polyethylene driven element. where the environment is significantly corrosive or at - a relatively inexpensive Shaft high or quite low thermoplastic, is used temperatures, it provides widely for bottles and other - Cylindrical piece of metal economical answer for containers used to carry rotating many problems machine parts such as Teflon pulleys and gears to Brass - also called transmit power or motion. - an alloy of copper and zinc. tetrafluoroethylene (TFE); Axle has uses similar to those of Bronze nylon, but is more - A stationary member of expensive primarily loaded in bending - an alloy of copper and tin with gears, pulleys, and Nominal Size wheels rotating on it. Manganese Bronze - a dimension is the size by Spindle - high-strength brass which it is referred to as a Tin Babbit B23-49 matter of convenience; is - A shaft or short axles on used to describe the general machine. - has a tin base and is a size of a part. general purpose nearing Key material, also used for die- Tolerance - A machine member castings - the permissible variation of employed at the interface of Hastelloy B the size of a dimension pair of a mating male and female circular cross- - an expensive alloy of nickel, Bilateral sectioned members to molybdenum, and iron (5%) - the size of a part is prevent relative angular that is very useful in the permitted to be either larger motion between these chemical industry or smaller than the given mating. Monel dimension Keyway - a group of nickel alloys, Unilateral - A female mating member primarily composed of - the size of a part may be which forms a groove in the nickel and copper (67% Ni, larger only, or smaller only shaft to which the key fits. 30% Cu) than the given dimension Coupling Creep Strength / Rupture Stress transmission shaft - A mechanical device for - when plastic deformation is - Those shafts used to uniting or connecting parts involved, it is the criterion transmit power between the of a mechanical system. for design at a particular source and the machines operating temperature at a absorbing the power. specified length of time ria dela cruz | bsme 4-1 | plm

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