Stability of elastic structures

MECH. RES. C O M M .

Vol.3, 337-341, 1976.

0

c,s. N E W S UDINE

- PALAZZO

DEL T O R S O

Following the P r e l i m i n a r y 1976, M e c h a n i c s

Pergamon Press.

Printed in USA.

No. 3 - 1976

- PIAZZA

GARIBALDI,

1 8 - TEL. 6 4 9 8 9

Information given in the CISM-NEWS No.2 -

Research Communications

3 no.

2, 139-142

(1976),

the subsequent

A N N O U N C E M E N T

presents more details

1976

in order to enable p r o s p e c t i v e p a r t i c i p a n t s

to decide now w h e t h e D and where they want to attend.

Changes may

still occur due to n o n - f o r e s e e n events though this is not expected for. Further

items about how to apply etc.,

the P r e l i m i n a r y

Information referred to above,

directly the Secretariat as above.

can be obtained

from

or by contacting

of C I S M in 1-331OO UDINE

(Italy),

As it is late now for the first E~TV~S Session,

address June 30 -

July 30, only the second session will be c o n s i d e r e d here.

THE EULER SESSION (October 4-30,

1976)

STABILITY OF ELASTIC STRUCTURES (October 4-13,

The classical

1976)

theory of stability of elastic

nearly e x c l u s i v e l y to linearized spite of the great achievements

structures was

and strictly static problems. of this theory,

In the first place,

rical imperfections

the effects of nonlinearities

a too narrow and geomet-

on the stability b e h a v i o u r of elastic

CISM N E W S

337

De-

it became obvious

in the recent decades that the classical approach was one.

limited

struc-

338

CISM NEWS

tures had to be taken into account,

Vol.3~ No.4 and an e x t e n s i o n of the theory,

closely related w i t h the name of Koiter,

did soon d e v e l o p

reason.

from the engineer's

Moreover,

modern

v o l v e m e n t w i t h dynamics structures ets, etc.), bility.

new methods d e v e l o p e d

introduced

rock-

aspects of sta-

in other fields of

Second Method.

of n o n c o n s e r v a t i v e

influence of damping:

aircrafts,

into the stability theory of elastic

for example Liapunov's

the i n v e s t i g a t i o n

in-

as well as with

(pipes,

d e m a n d e d the inclusion of the dynamic

As a consequence,

structures,

culiar

and control of structures

e x p o s e d to rapidly moving m e d i a

e n g i n e e r i n g were

include

tasks following

for that

Also,

problems,

Damping can d e s t a b i l i z e

one had to and the pe-

a structure

in the p r e s e n c e of certain other n o n c o n s e r v a t i v e

forces.

more,

and taking there-

considering

stability as a dynamic process

fore inertia forces timal d i s t r i b u t i o n

into account,

did require studying

of the structure masses.

theory had to deal with stochastic dynamic

stability of structures,

parameters various

processes

d e f i n i n g of concepts

connected with the and load

quantities.

and many others,

into a m o d e r n theory of stability.

the op-

the m o d e r n

structural p a r a m e t e r s

being p o s s i b l y the randomly given

topics m e n t i o n e d here,

Finally,

Further-

All these

had to be built

The result was an extensive

and r e d e s i g n i n g

of methods.

Thus,

a reorien-

tation of e v e r y b o d y concerned with the stability of elastic tures has become The course

re-

struc-

indispensable.

is supposed to assist this r e o r i e n t a t i o n

all those i n t e r e s t e d

in the subject and already

stability of elastic

structures

lation of stability.

The course will consist

to a m o d e r n

and to introduce

familiar with the

and most recent formuof the following

five

sections: I.

Mathematical

2.

Nonlinear

3.

Control of Perfect and Imperfect Structures, the S t a b i l i t y Problems Involved;

4.

Dynamic and Stochastic

5.

Stability of Specific Design Problems;

covering the various value of the course

Foundations;

Problems

and M a t r i x Formulation; and

Stability; Structures

subjects m e n t i o n e d

and Related

previously.

The academic

lies in its t r a n s m i t t i n g new concepts

and

Vol.3, No.4

CISM NEWS

339

methods in mathematical physics related to the specific subject of ~he course.

Its practical value lies in the fact that by providing

the scientifically

inclined engineer with new tools,

it will enable

him to tackle the challenging stability problems posed by technology in its present phase of development covering specifically problems of aero and space mechanics. Invited lecturers S.T. Ariaratnam

(tentative list):

(University of Waterloo);

Institute of Technology); Waterloo);

H.H.E. Leipholz

K. Huseyin

A.H. Chilver

(Cranfield

(Department of Systems Design,

(University of Waterloo);

J. Roorda

(University of Waterloo). Coordinator: H.H.E.

Leipholz

(University of Waterloo).

DYNAMIC PHOTOELASTICITY AND PHOTOPLASTICITY (October 14-22, 1976) Dynamic photoelasticity

and photoplasticity

are optical methods

utilizing the phenomena of dielectric polarization caused by mechanical disturbances

in certain transparent media.

Dynamic photoelasticity

is usually applied to the study of the

problems of wave propagation primarily in elastodynamics

and of the

states of plane stress. Many areas of applications can be cited including civil engineering structures and machine elements, zation of sequencing explosions

optimi-

in a mine in order to obtain the

greatest shearing stress propagation of cracks, etc. Recent develo p m e n ~ concern the improvement of systems subjected to dynamic loading programmes,

the utilization of new materials

(e.g. orthotropic),

etc. The use of pulsed lasers leads to decisive progress in the precision of measurements techniques, particularly

and permits the application of holography

and with it, stress separation.

This possibility

is

interesting when materials are being used for which

the fracture load is near to the elastic limit

(high strength alloys