类别 全部 - material - gravity - joints - forces

作者:grac3311 g 9 年以前

682

Forms and Function

Different types of structures include frame, mass, and shell constructions. Frame structures consist of a skeleton made from a strong material and are secured to the ground, examples being homes and snowshoes.

Forms and Function

Forms and Function

Internal and External Forces

Internal
shear

tears the structure in opposite parallel directions

torsion

twists structure

tension and compression

when too many books are placed on a shelf the shelf bends resulting in tension and compression

Compression

squashes structures resulting in decreased length

Tension

stretches structures resulting in increased length

External
dead loads

the weight of the materials used to build the structure

live loads

objects on or within structure

impact forces

strong winds

affect structure from outside

Stability and Center of Gravity

Center of Gravity
unstable structures like the tower of pisa's center of gravity is inside but not centered over the support base
stable structures can have their center of gravity outside or not centered over the support base
Stability
a stable structure can support a live load and the support base/points are not altered
a structure can become unstable if it can not support the live load
a chair may become unstable if a chair leg is lifted above the ground

Design Features

Joints
rigid joints prevent movement
mobile joints allow movement
any place where pieces are held together
Material
composite materials are using two different materials to use both benifits
chosen based on strength needed, environment etc
Shape
triangular shapes are strong
corrugations increase strength in structure
used to spread force
made to withstand forces
Function
may need to support humans, support wind etc
consider location
what the structure is supposed to do

Types of Structures

Shell
egg cartons, food cans, pipes
little building material
strong, hollow
Frame
homes, snowshoes
lightweight designs need to be fastened to ground
skeleton of strong material
Mass
snow sculptures, dams, mountains
held in place by own weight
built by piling materials