lilernoEngineeringOpening Lilerno
Chapter 12 · Guided self-study
Intro + external course studyJustify a material choice using properties, processing, cost, and environment.
Build the idea
An original introduction, worked example and practice, followed by a curated reading sequence. The external courses supply deeper teaching and problem sets.
This guide is an orientation, not a complete university module. Practical work needs suitable facilities, safety review and supervision.
Start with these prerequisites
Shared science foundations
A material is not selected by strength alone. Structure, processing, environment, cost and failure behaviour determine whether it fits a task.
Module lens
Density helps estimate mass; stiffness, strength and failure behaviour require other evidence and conditions.
Alloy, heat treatment, temperature, loading rate and manufacturing history can change properties. Use a named material grade and traceable datasheet for actual design; generic values in an exercise are only assumptions.
Bonding and microstructure help explain stiffness, plasticity, fracture and corrosion. A static strength calculation does not establish fatigue life. Composites can be direction-dependent, so a single scalar property may be inadequate.
See the relationship
Change one quantity, watch the graph respond, then explain the result in your own words.
Predict → change → explain
Does the lightest equal-volume part necessarily have the same stiffness?
Axes: Volume (cm³) → Mass (g). Bounds may rescale when inputs change.
At 100 cm³: 2.7 → 270 g; 7.8 → 780 g; chosen density → 400 g.
Rounded exercise densities 2.7 and 7.8 g/cm³, plus an adjustable hypothetical density. No material grade or strength claim.
Original Lilerno illustration. Inputs are illustrative; this is not experimental evidence or a design rating.
| Series | Volume (cm³) | Mass (g) |
|---|---|---|
| ρ = 2.7 | 0 | 0 |
| ρ = 2.7 | 2.5 | 6.75 |
| ρ = 2.7 | 5 | 13.5 |
| ρ = 2.7 | 7.5 | 20.25 |
| ρ = 2.7 | 10 | 27 |
| ρ = 2.7 | 12.5 | 33.75 |
| ρ = 2.7 | 15 | 40.5 |
| ρ = 2.7 | 17.5 | 47.25 |
| ρ = 2.7 | 20 | 54 |
| ρ = 2.7 | 22.5 | 60.75 |
| ρ = 2.7 | 25 | 67.5 |
| ρ = 2.7 | 27.5 | 74.25 |
| ρ = 2.7 | 30 | 81 |
| ρ = 2.7 | 32.5 | 87.75 |
| ρ = 2.7 | 35 | 94.5 |
| ρ = 2.7 | 37.5 | 101.3 |
| ρ = 2.7 | 40 | 108 |
| ρ = 2.7 | 42.5 | 114.8 |
| ρ = 2.7 | 45 | 121.5 |
| ρ = 2.7 | 47.5 | 128.3 |
| ρ = 2.7 | 50 | 135 |
| ρ = 2.7 | 52.5 | 141.8 |
| ρ = 2.7 | 55 | 148.5 |
| ρ = 2.7 | 57.5 | 155.3 |
| ρ = 2.7 | 60 | 162 |
| ρ = 2.7 | 62.5 | 168.8 |
| ρ = 2.7 | 65 | 175.5 |
| ρ = 2.7 | 67.5 | 182.3 |
| ρ = 2.7 | 70 | 189 |
| ρ = 2.7 | 72.5 | 195.8 |
| ρ = 2.7 | 75 | 202.5 |
| ρ = 2.7 | 77.5 | 209.3 |
| ρ = 2.7 | 80 | 216 |
| ρ = 2.7 | 82.5 | 222.8 |
| ρ = 2.7 | 85 | 229.5 |
| ρ = 2.7 | 87.5 | 236.3 |
| ρ = 2.7 | 90 | 243 |
| ρ = 2.7 | 92.5 | 249.8 |
| ρ = 2.7 | 95 | 256.5 |
| ρ = 2.7 | 97.5 | 263.3 |
| ρ = 2.7 | 100 | 270 |
| ρ = 2.7 | 102.5 | 276.8 |
| ρ = 2.7 | 105 | 283.5 |
| ρ = 2.7 | 107.5 | 290.3 |
| ρ = 2.7 | 110 | 297 |
| ρ = 2.7 | 112.5 | 303.8 |
| ρ = 2.7 | 115 | 310.5 |
| ρ = 2.7 | 117.5 | 317.3 |
| ρ = 2.7 | 120 | 324 |
| ρ = 2.7 | 122.5 | 330.8 |
| ρ = 2.7 | 125 | 337.5 |
| ρ = 2.7 | 127.5 | 344.3 |
| ρ = 2.7 | 130 | 351 |
| ρ = 2.7 | 132.5 | 357.8 |
| ρ = 2.7 | 135 | 364.5 |
| ρ = 2.7 | 137.5 | 371.3 |
| ρ = 2.7 | 140 | 378 |
| ρ = 2.7 | 142.5 | 384.8 |
| ρ = 2.7 | 145 | 391.5 |
| ρ = 2.7 | 147.5 | 398.3 |
| ρ = 2.7 | 150 | 405 |
| ρ = 2.7 | 152.5 | 411.8 |
| ρ = 2.7 | 155 | 418.5 |
| ρ = 2.7 | 157.5 | 425.3 |
| ρ = 2.7 | 160 | 432 |
| ρ = 2.7 | 162.5 | 438.8 |
| ρ = 2.7 | 165 | 445.5 |
| ρ = 2.7 | 167.5 | 452.3 |
| ρ = 2.7 | 170 | 459 |
| ρ = 2.7 | 172.5 | 465.8 |
| ρ = 2.7 | 175 | 472.5 |
| ρ = 2.7 | 177.5 | 479.3 |
| ρ = 2.7 | 180 | 486 |
| ρ = 2.7 | 182.5 | 492.8 |
| ρ = 2.7 | 185 | 499.5 |
| ρ = 2.7 | 187.5 | 506.3 |
| ρ = 2.7 | 190 | 513 |
| ρ = 2.7 | 192.5 | 519.8 |
| ρ = 2.7 | 195 | 526.5 |
| ρ = 2.7 | 197.5 | 533.3 |
| ρ = 2.7 | 200 | 540 |
| ρ = 7.8 | 0 | 0 |
| ρ = 7.8 | 2.5 | 19.5 |
| ρ = 7.8 | 5 | 39 |
| ρ = 7.8 | 7.5 | 58.5 |
| ρ = 7.8 | 10 | 78 |
| ρ = 7.8 | 12.5 | 97.5 |
| ρ = 7.8 | 15 | 117 |
| ρ = 7.8 | 17.5 | 136.5 |
| ρ = 7.8 | 20 | 156 |
| ρ = 7.8 | 22.5 | 175.5 |
| ρ = 7.8 | 25 | 195 |
| ρ = 7.8 | 27.5 | 214.5 |
| ρ = 7.8 | 30 | 234 |
| ρ = 7.8 | 32.5 | 253.5 |
| ρ = 7.8 | 35 | 273 |
| ρ = 7.8 | 37.5 | 292.5 |
| ρ = 7.8 | 40 | 312 |
| ρ = 7.8 | 42.5 | 331.5 |
| ρ = 7.8 | 45 | 351 |
| ρ = 7.8 | 47.5 | 370.5 |
| ρ = 7.8 | 50 | 390 |
| ρ = 7.8 | 52.5 | 409.5 |
| ρ = 7.8 | 55 | 429 |
| ρ = 7.8 | 57.5 | 448.5 |
| ρ = 7.8 | 60 | 468 |
| ρ = 7.8 | 62.5 | 487.5 |
| ρ = 7.8 | 65 | 507 |
| ρ = 7.8 | 67.5 | 526.5 |
| ρ = 7.8 | 70 | 546 |
| ρ = 7.8 | 72.5 | 565.5 |
| ρ = 7.8 | 75 | 585 |
| ρ = 7.8 | 77.5 | 604.5 |
| ρ = 7.8 | 80 | 624 |
| ρ = 7.8 | 82.5 | 643.5 |
| ρ = 7.8 | 85 | 663 |
| ρ = 7.8 | 87.5 | 682.5 |
| ρ = 7.8 | 90 | 702 |
| ρ = 7.8 | 92.5 | 721.5 |
| ρ = 7.8 | 95 | 741 |
| ρ = 7.8 | 97.5 | 760.5 |
| ρ = 7.8 | 100 | 780 |
| ρ = 7.8 | 102.5 | 799.5 |
| ρ = 7.8 | 105 | 819 |
| ρ = 7.8 | 107.5 | 838.5 |
| ρ = 7.8 | 110 | 858 |
| ρ = 7.8 | 112.5 | 877.5 |
| ρ = 7.8 | 115 | 897 |
| ρ = 7.8 | 117.5 | 916.5 |
| ρ = 7.8 | 120 | 936 |
| ρ = 7.8 | 122.5 | 955.5 |
| ρ = 7.8 | 125 | 975 |
| ρ = 7.8 | 127.5 | 994.5 |
| ρ = 7.8 | 130 | 1014 |
| ρ = 7.8 | 132.5 | 1034 |
| ρ = 7.8 | 135 | 1053 |
| ρ = 7.8 | 137.5 | 1073 |
| ρ = 7.8 | 140 | 1092 |
| ρ = 7.8 | 142.5 | 1112 |
| ρ = 7.8 | 145 | 1131 |
| ρ = 7.8 | 147.5 | 1151 |
| ρ = 7.8 | 150 | 1170 |
| ρ = 7.8 | 152.5 | 1190 |
| ρ = 7.8 | 155 | 1209 |
| ρ = 7.8 | 157.5 | 1229 |
| ρ = 7.8 | 160 | 1248 |
| ρ = 7.8 | 162.5 | 1268 |
| ρ = 7.8 | 165 | 1287 |
| ρ = 7.8 | 167.5 | 1307 |
| ρ = 7.8 | 170 | 1326 |
| ρ = 7.8 | 172.5 | 1346 |
| ρ = 7.8 | 175 | 1365 |
| ρ = 7.8 | 177.5 | 1385 |
| ρ = 7.8 | 180 | 1404 |
| ρ = 7.8 | 182.5 | 1424 |
| ρ = 7.8 | 185 | 1443 |
| ρ = 7.8 | 187.5 | 1463 |
| ρ = 7.8 | 190 | 1482 |
| ρ = 7.8 | 192.5 | 1502 |
| ρ = 7.8 | 195 | 1521 |
| ρ = 7.8 | 197.5 | 1541 |
| ρ = 7.8 | 200 | 1560 |
| ρ = 4 | 0 | 0 |
| ρ = 4 | 2.5 | 10 |
| ρ = 4 | 5 | 20 |
| ρ = 4 | 7.5 | 30 |
| ρ = 4 | 10 | 40 |
| ρ = 4 | 12.5 | 50 |
| ρ = 4 | 15 | 60 |
| ρ = 4 | 17.5 | 70 |
| ρ = 4 | 20 | 80 |
| ρ = 4 | 22.5 | 90 |
| ρ = 4 | 25 | 100 |
| ρ = 4 | 27.5 | 110 |
| ρ = 4 | 30 | 120 |
| ρ = 4 | 32.5 | 130 |
| ρ = 4 | 35 | 140 |
| ρ = 4 | 37.5 | 150 |
| ρ = 4 | 40 | 160 |
| ρ = 4 | 42.5 | 170 |
| ρ = 4 | 45 | 180 |
| ρ = 4 | 47.5 | 190 |
| ρ = 4 | 50 | 200 |
| ρ = 4 | 52.5 | 210 |
| ρ = 4 | 55 | 220 |
| ρ = 4 | 57.5 | 230 |
| ρ = 4 | 60 | 240 |
| ρ = 4 | 62.5 | 250 |
| ρ = 4 | 65 | 260 |
| ρ = 4 | 67.5 | 270 |
| ρ = 4 | 70 | 280 |
| ρ = 4 | 72.5 | 290 |
| ρ = 4 | 75 | 300 |
| ρ = 4 | 77.5 | 310 |
| ρ = 4 | 80 | 320 |
| ρ = 4 | 82.5 | 330 |
| ρ = 4 | 85 | 340 |
| ρ = 4 | 87.5 | 350 |
| ρ = 4 | 90 | 360 |
| ρ = 4 | 92.5 | 370 |
| ρ = 4 | 95 | 380 |
| ρ = 4 | 97.5 | 390 |
| ρ = 4 | 100 | 400 |
| ρ = 4 | 102.5 | 410 |
| ρ = 4 | 105 | 420 |
| ρ = 4 | 107.5 | 430 |
| ρ = 4 | 110 | 440 |
| ρ = 4 | 112.5 | 450 |
| ρ = 4 | 115 | 460 |
| ρ = 4 | 117.5 | 470 |
| ρ = 4 | 120 | 480 |
| ρ = 4 | 122.5 | 490 |
| ρ = 4 | 125 | 500 |
| ρ = 4 | 127.5 | 510 |
| ρ = 4 | 130 | 520 |
| ρ = 4 | 132.5 | 530 |
| ρ = 4 | 135 | 540 |
| ρ = 4 | 137.5 | 550 |
| ρ = 4 | 140 | 560 |
| ρ = 4 | 142.5 | 570 |
| ρ = 4 | 145 | 580 |
| ρ = 4 | 147.5 | 590 |
| ρ = 4 | 150 | 600 |
| ρ = 4 | 152.5 | 610 |
| ρ = 4 | 155 | 620 |
| ρ = 4 | 157.5 | 630 |
| ρ = 4 | 160 | 640 |
| ρ = 4 | 162.5 | 650 |
| ρ = 4 | 165 | 660 |
| ρ = 4 | 167.5 | 670 |
| ρ = 4 | 170 | 680 |
| ρ = 4 | 172.5 | 690 |
| ρ = 4 | 175 | 700 |
| ρ = 4 | 177.5 | 710 |
| ρ = 4 | 180 | 720 |
| ρ = 4 | 182.5 | 730 |
| ρ = 4 | 185 | 740 |
| ρ = 4 | 187.5 | 750 |
| ρ = 4 | 190 | 760 |
| ρ = 4 | 192.5 | 770 |
| ρ = 4 | 195 | 780 |
| ρ = 4 | 197.5 | 790 |
| ρ = 4 | 200 | 800 |
| Chosen part | 100 | 400 |
Save your place when you finish reading.
Original Lilerno example
Compare masses of two equal 100 cm³ parts using illustrative densities 2.7 and 7.8 g/cm³.
Mass = density × volume.
First part: 2.7 × 100 = 270 g.
Second part: 7.8 × 100 = 780 g.
This compares mass only, not equal stiffness or equal strength.
Test the model
Open learning, traceable sources
Work in this order. These links open the publisher’s material; free access does not always permit republication.
MIT OpenCourseWare · Spring 2004
Start with: Material behaviour and experimental characterization
Study how test results support a constitutive model, then compare processing and failure mechanisms.
MIT OpenCourseWare
Start with: Process physics
Relate one manufacturing process to microstructure and achievable properties.
Recall, then record
Close the explanation and answer these in your own words. Return tomorrow, then again later in the week.
Which grade and condition?
What changes with temperature?
Why does low mass not guarantee a good design?
Create a material-selection table with property source, units, conditions, uncertainty and reasons for rejecting alternatives.
Self-reported tasks, not an assessment of mastery or university credit. Reading a page does not complete a chapter.
Loading local record…
Open learning, traceable sources
Original Lilerno lessons and diagrams, supported by these references. Free access does not always permit republication. Links open the publisher’s material.
Process physics, manufacturing systems, quality, homework and a documented yo-yo design project.
CC BY-NC-SA 4.0 except separately credited material. Linked for external study, not reproduced. Some assigned textbooks/software require separate access.
Open source ↗Rights / publisher record ↗Mechanical behaviour, material selection, and experimental work.
CC BY-NC-SA, except marked exceptions; external study only.
Open source ↗Rights / publisher record ↗