University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Homework 7: two FEM problems, postedyesterday, due Th October 22.

RQ#5 on FEM on Tuesday Oct 20. Read Chapters 13-15 (omit 16). Only basic questions.

Recitation next week on Friday Oct 23 will cover beams by DF and FEM (two problems)

Midterm exam Friday Oct 29, announced in HW 7.

Near Term Timetable

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Midterm Exam 2 and HW 5 have beengraded, may be picked up from table

Solutions for both are posted on the Web

Returned Today

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

To be held on Friday October 15, at Visions Lab(ECAE 1B73) - No recitations that day.To get access with your Buff Card and get an account, register at the OIT site specified on the ANSYS tutorial.Attendance recommended but not required

Demo is a hands-on, self-learning (individual) tutorial.Once in, sit at any empty computer and try logging inUsing your Identikey and PW. T.A.s available to help.

Access to VL is 24/7, except if classes are being held

ANSYS Demos for Computer Portion of Lab 2

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Because of limited seating (physically 25 workstations) the demo will be divided into four roughly-one-hour subsections

Sec 011: 1 PM and 2 PM Sec 012: 3 PM and 4 PM

Student distribution on next slide

Demo Times

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Section 011 (1-3 PM) Splitting

A-L 1 PMM-Z 2 PM

A-L 3 PMM-Z 4 PM

Section 012 (3-5 PM) Splitting

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Note: members of a group need notattend the same demo subsection, since the tutorial is individual

No Grouping Necessary

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

A Short Pictorial Introduction to FEM

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

such as beams, ribs and spars,were sufficient for modelinglow aspect ratio aircraft structures

(e.g. Lockheed Constellation,pictured on left)

Before 1950, standard structural elements

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

... starting about 1952 as a modeling tool to simulate delta wing military aircraft on digital computers

Digital computers began to be commercially sold by 1951. Only aerospace companies and some government agencies could afford them (a vacuum-tube monster weighting several tons and with the power of an iPhone cost theequivalent of $100M today)

The modern FEM was developed ...

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Most of the pre-1960 work was done at a few places

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

A key 1956 paper described the DSM as used today

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

... but it had a marketing problem:

no brand name

The method was well on its way by 1960

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Name was coined by Ray Clough in 1960

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

b. 1921, Seattle

served in Air Force during WWII

Ph.D. Aero & Astro MIT, 1950

joined Civil Engrg faculty at UC Berkeley, 1951

avid mountaineer & skier (holds many climbing records)

Ray Clough’s early career I

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

spent 1952-54 summers at Boeing at Jon Turner’s group so he could go mountain climbing on weekends

modern FEM started by 1956 JAS paper by Turner, Clough, Martin & Topp

back at Berkeley, became interesting in Civil applications, especially earthquake engineering

formed FEM research group in 1958

Ray Clough’s early career II

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

First Civil structure analyzed by FEM (1962)

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

20021956

Ray with Kurt Gerstle (his 1st student) on left pic

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

gave up FEM research in 1972 for earthquake engineering

head of NSF Earthquake Engineering Center at Richmond, CA, 1974-82

retired from Berkeley 1987

honored with National Medal of Science, 1994

Ray Clough’s late career

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

An Unimpeachable Gentleman

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

By 1970, FEM (DSM) had taken over computational mechanics and was expanding beyond structures

Some samples follow

Explosive Success ...

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

F-16 Structural Model

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

95% ofelements areHPSHEL318 DOF shells

F-16 Exterior Surface Zoom

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Some solid elements (bricks & tets) used for “wing fingers”

F-16 Interior Structure Zoom

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Liquid Natural Gas (LNG) Ship - Global FEM Model

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Stepwise Construction of Global Model

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

“Hot Spots “ Detailed Local Models

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Wave Motion and Hull Pressures

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

470 m high including superstructure

240 000 m3 of concrete

104 000 tons of steel reinforcement

Design life of 50 years

Largest man-made object ever moved

Supplies 10 percent of Europe’s gas consumption

The Troll Platform

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Floating TLP Platform

Made of reinforced concrete

16 vertical anchoring lines (tethers)

30 000 of pre-tensioning

Transverse stiffness supplied by secondary geometric effects

The Heidrun Platform

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Last But Not Least ...

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

16-bay Truss for Lab #2: FEM Model (Mathematica)

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

Idealization Process

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

FEM-DSM Breakdown

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

FEM-DSM Assembly & Solution

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

The Example TrussThe Example Truss

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015

The Truss ExampleThe Truss Example

University of Colorado - Intro to Aerospace Structures (ASEN 3112) - Fall 2015