List of alloys that can be used for legs / boom is too thick!!! - Jarrett D

LEGS
we have estimated that the maximum amount of stress any part of the legs are exposed to is around 8mpa. Although our calculations need to be refined it is unlikely that this value will not be greatly affected. Therefore i have put together a list of aluminium alloys that can be used.

alloy....................... ...compression yield stregnth (mpa)
Aluminum 2014-O .................................................185
Aluminum 2014-T4; 2014-T451 ............................425

Aluminum 2014-T6; 2014-T651 ...........................470

Aluminum 2048-T851 Plate .................................420

Aluminum 2618-T61.............................................370

Aluminum 5086-H112 ..........................................270

Aluminum 5086-H116; 5086-H32 .......................290

Aluminum 5086-H34 ..........................................325

Aluminum 5086-O ..............................................160

Aluminum 7039-T61 ..........................................390

Aluminum 7039-T64 ..........................................410

Aluminum 7178-T6; 7178-T651 ........................530

Aluminum 7178-T76; 7178-T7651 ...................460

Aluminum 7475-T7351 ...................................380

Aluminum A206.0-T7 Casting Alloy ..............372

Aluminum 206.0-T7 Casting Alloy ................372

Aluminum 208.0-F, Sand Cast .....................105

Aluminum 242.0-T21, Sand Cast ..................125

Aluminum 242.0-T571, Permanent Mold Cast .235

Aluminum 242.0-T571, Sand Cast ....................235

Aluminum 242.0-T61, Permanent Mold Cast ....305

Aluminum 242.0-T77, Sand Cast .....................165

Aluminum 295.0-T4, Sand Cast ......................115

Aluminum 295.0-T6, Sand Cast .....................170

Aluminum 295.0-T62, Sand Cast ...................235

Aluminum 296.0-T4, Cast ...............................140

Aluminum 296.0-T6, Permanent Mold Cast .180

Aluminum 296.0-T7, Cast ..............................140

Aluminum 319.0-F, Permanent Mold Cast .....130

Aluminum 319.0-F, Sand Cast ........................130

Aluminum 319.0-T6, Sand Cast ......................170

Aluminum 336.0-T551, Permanent Mold Cast 193

Aluminum 336.0-T65, Permanent Mold Cast ...296

Aluminum 354.0-T61, Permanent Mold Cast ....250

Aluminum 355.0-T71, Permanent Mold Cast .....215

Aluminum 355.0-T71, Sand Cast ........................205

Aluminum 355.0-T51, Permanent Mold Cast ....165

Aluminum 355.0-T51, Sand Cast .......................165

Aluminum 355.0-T61, Cast ................................215

Aluminum 355.0-T62, Permanent Mold Cast .....275

Aluminum 355.0-T6, Permanent Mold Cast ........185

Aluminum 355.0-T6, Sand Cast ..........................180

STEEL WIRE
I have calculted that if we use steel wire with a thickness of 1cm to lift the objects, it will be exposed to a maximum tension of 124.9 mpa. Therefore a medium carbon steel should be used to create the wire as it typically has a tensile strength much higher than this.

mass estimation of the legs and boom
using the dimensions given on the cad drawings i calculated a rough estimate of the mass of the crane legs and boom.

legs
given that all of the aforementioned alloys have a density between 2800 - 2650 kg/m^3

mass of the crane foot extender= 3.69-3.50kg
'' '' crane foot = 1.76- 1.67kg
'' ''crane leg = 3.25-3.08kg
'' ''crane shoulder = 5.00 - 4.74kg

Boom
when estimating the boom i came across something very worrying. i will show my calculations so someone can spot a mistake if i have made one.

density of carbon steel = 7800kg/m^3

cross sectional area of boom = (0.05x0.06)+2(0.02x0.07)= 5.8x10^-3 m^2
volume of boom = 5.1 x 5.8x10^-3 = 0.02958 m^3
mass of boom = 7800 x 0.02958 = 230.724 kg

here you can see that the boom is very heavy, therefore i suggest we make it thinner or shorter unless my calculations are wrong.

all facts and figures were obtained from http://www.matweb.com/