science unit D Flashcards
aesthetics
the pleasing appearance or effect that an object has, (not all structures need to be aesthetically pleasing)
describe a frame structure
made up of rigid arrangement of parts, or structural components fastened together. can be arranged in 2 & 3 dimensions. compared to solid, they are lighter
describe a shell structure
has a solid outer surface and a hollow inner area that can be in a rounded or flat shape. the rounded ones are usually stronger because the curves distribute the load around the surface. lighter then solid, stronger than frame
describe a solid structure
formed in a solid piece of strong material, little or no space inside, relies on its own mass to resist the forces that act on it. stronger than all, more massive and harder to move
function
use or purpose of something
is a music stand a solid, frame or shell structure?
frame
is a sports dome a solid, frame or shell structure?
shell
is a hydro electric dam a solid, frame or shell structure?
solid
structure
object that provides support
structural strength
refers to a structures capacity to hold itself up as well as any weight added
structural stability
structures ability to maintain its position even when it is being acted on by a force .
what do you have to verify in a structure
the climate, culture, tradition, tech, economics
what are some homes in other places of the world?
yurts, tents, gel, tepee
whats a force
a push or pull that tends to cause an object to changes its movement or shape
how does magnitude effect a force
the magnitude or size of the force - the bigger a forces magnitude, stronger it is and the more effect it will have on a structure
how does direction effect a force
the direction in which a force acts on a structure also determines what effect that forces will have
how does location effect a force
the location on a structure where a force is applied affects the outcome
external force
a force that is applied on a structure by something else (ex, when you walk in the wind, external force)
mass
the amount of matter in an object. the more mass an object has, the greater the gravitational force
center of gravity
a point where theres a downward force of gravity acting on a structure, whats called the center of gravity.
how is the center of gravity applied to stability
when a structure is supported at the center of gravity, it will stay balanced. the location of the structure determines the structures stability
symmetry
a balanced arrangement of mass that occurs on opposite sides of a line or plane, or around a center or axis.
whats a load
an external force on a structure
what are static and dynamic loads
the weight of a structure and non moving load it supports is called a static load. || an external force that moves or changes with time - dynamic. it can change very quickly, also called a live load.
conditions to decide what type of bridge to build
what the bridge with be crossing
what kind of loads the bridge will be supporting
beam bridge
the most common bridge used, is flat, and supported at 2 ends. a longer beam bridge may be supported by other stuff
truss bridge
light weight, but strong, made of trusses (triangle) along its sides.
suspension bridge
hangs between two ends that holds it up, modern one has tall towers on ends that supports main cables. those cables are anchored in concrete, smaller cables support roadway
arch bridge
designed to with stand heavy loads. the dynamic loads of people cause pieces of wood or stone in arch to push against the pieces.
performance requirements
conditions that a structure must meet. performance requirements also apply to many other aspects of a structure like safety, effectiveness, and purpose
internal force
force that one part of a structure exerts on other parts of the same structure. force that acts within a structure
compression
force that acts to squeeze an object or push parts within an object together.
tension
force that acts to stretch and pull apart something. can cause lengthening and possibly snapping of a component
shear
force that acts to push parts that are in contact with each other in opposite directions.
complementary forces
when different kinds of internal forces act on a structure at the same time.
structural components (arch, beam, I beam, girders)
can support a large load ||| simple beam is a flat structure supported at both ends. I beams have less mass then a solid beam, shape of it gives it strength. in a shape of a rectangular prism (boxish).
structural components (truss, cantilever, columns)
truss - frame work of beams joined together, form of interlocking triangles. || beam that is only supported at one end, bends in a n shape. || solid that can stand by itself, can support beams.
what are some properties of material
brittleness, hardness, resistance to heat, compression
what is deformation
change of shape in a structure or any structural component, because the material is unable to resist the load acting on it.
joints that rely on friction
nail, screw, tack, or staple
joints that rely on bonding
(common) glue, tape, cement, welds
fixed vs movable
fixed joints are rigid to prevent any movement
moveable joints are flexible or mobile so that the structure can move
margin of safety
the limits within which a structure safety performance is felt to be acceptable
testing and monitoring for safety
to ensure the structure wont fail when the consumers use it (forces)
corrugation
process of forming a material into wave like ridges or folds, perfect for making a sturdy/light divider
lamination
gluing layers of a material together to create a strong bond
way of strengthening component arrangements
making greater use of trusses and arches
kevlar uses
tires, sporting goods, fiber optic cables
evaluation of products
cost, benefits, safety, impact on environment
