Bridges, Truss Terminology, PLTW POE Lesson 4.1 Statistics, pltw poe material and trusses and material testing and properties of materials
Tension Force
A body subjected to a pull.
Static Equilibrium
A condition where there are no net external forces acting upon a particle or rigid body and the body remains at rest or continues at a constant velocity.
Moment of Inertia
A mathematical property of a cross section that is concerned with a surface area and how that area is distributed about a centroidal axis.
Statistical Process Control
A method of monitoring, controlling, and ideally improving a process through statistical analysis. Its four basic steps include measuring the process, eliminating variances in the process to make it consistent, monitoring the process, and improving the process to its best target value.
Scalar
A physical quantity that has magnitude only.
Vector Quality
A quantity that has both a magnitude and direction.
Sample Space
A set of all possible outcomes or events in an experiment that cannot be further broken down.
Statically Indeterminate
A structure or body which is over-constrained such that there are more unknown supports than there are equations of static equilibrium.
Event
A subset of a sample space.
Roller Support
A support that only prevents a beam from translating in one direction.
Pinned Support
A support that prevents translation in any direction.
Simple Truss
A truss composed of triangles, which will retain its shape even when removed from supports.
Planar Truss
A truss that lies in a single plane often used to support roofs and bridges.
Deviation
Amount of difference between a value and the mean.
Experiment
An activity with observable results.
Mean
Arithmetic average.
Normal Distribution
Bell-shaped probability distribution.
Pie Chart
Categorical data graph %.
Bar Chart
Categorical data graph.
Accuracy
Degree of conformity of a measure to a standard value.
Newton's First Law
Every body or particle continues at a state of rest or uniform motion in a straight line, unless it is compelled to change that state by forces acting upon it.
Frequency Polygons
Frequency distribution graph.
Histogram
Frequency distribution graph.
Frequency Distribution
Listing of data values along with their corresponding frequencies.
Data Variation
Measure of data scatter.
Mean Deviation
Measure of variation equal to the sum of the deviations of each value from the mean.
Median
Middle value of a set of values arranged in order of magnitude.
Data
Numbers or information describing some characteristic.
Structure
Something made up of interdependent parts in a definite pattern of organization, such as trusses, frames, or machines.
Probability
The calculated likelihood that a given event will occur.
Newton's Second Law
The change of motion of the body is proportional to the net force imposed on the body and is in the direction of the net force.
Statistics
The collection, evaluation, and interpretation of data.
Variance
The difference between samples.
Tolerance
The difference between the maximum and minimum dimensions allowed within the design of a product.
Bayes' Theorem
The probability of an event occurring based upon other event probabilities.
Reliability
The probability of satisfactory operation of the product in a given environment over a specified time interval.
Outcome
The result of an experiment.
Resultant Force
The resultant of a system of force is the vector sum of all forces.
Sense
The sense of a vector is the direction of the vector relative to its path and indicated by the location of the arrow.
Standard Deviation
The square root of the variance.
Quality Assurance
The use of quality control techniques associated with a process.
Mode
The value that occurs most frequently.
Process Control
To monitor and control a process so that the quality of the output/product improves.
Qualitative Data
Values that possess names or labels.
Quantitative Data
Values that represent a measurable quantity.
floor beam
a cross piece running under the deck.
Axial Stress
a force in a direction parallel to the long axis of the structure
Resilience
a mechanical property of how effective the material is at absorbing mechanical energy
Toughness
a mechanical property of how effective the material is at handling overloading before it fractures
stringer
a member supporting the deck that runs the length of the bridge span
member
a particular piece of a truss, providing support through its compression or tension.
force
a push or a pull; a vector quantity.
deck
a surface that rests between the two side trusses.
3 things that effect new and changing materials
advancements in materials, technology, and science
joint
another name for a connection; the point at which two structural pieces come together.
Deformation
any alteration of shape or dimensions of a body caused by stress
Variance
average of the squared difference from the mean
Strain
change in the length of an object in some direction per unit
Statistics
collection and analysis of numerical data in large quantities
Failure Point
condition caused by collapse, break, or bending, so that a structure can no longer fulfill its purpose
Elements
consist of only one type of particle or atom; cannot be broken down
span
distance from pier to pier
True or False: An element has similar properties as you move across a row in the periodic table
false
True or False: An elements properties are different when you have very little (<10,000 atoms) and a lot (greater 1.0x10^40 atoms) in one part
false
tension
force of pulling or stretching
compression
force of pushing
Stress-Strain Curve
graphical representation of a material's mechanical properties
Shear Stress
how easily a material can be twisted
Elastic Limit
maximum stress that a material will withstand without permanent deformation
Standard Division
measurement of variability
beam bridge
most common type of bridge/ least complicated
Quality Control
operational techniques necessary to satisfy all requirements; process monitoring
road bed
platform cars go across
Proportional Limit
point at which the deformation is no longer directly proportional to the applied force
Rupture Strength
stress developed in a material at rupture
Materials
substances out of which all things are made
Ultimate Stress
tensile strength; the maximum load a material in rectangular or cylindrical form can carry
Destructive Testing
test methods used to examine an object or system causing permanent damage to its usefulness
Non-Destructive Testing
test methods used to examine an object or system does not cause permanent damage to its usefulness
Problem Solving
the ability to get answers to questions through a conscious, organized process
Tension
the condition of a string, wire, or rod that is stretched between two points
Stress
the force acting across a unit area in a solid material resisting external forces
Elongation
the fractional increase in a material's length due to stress or tension
bottom chord
the line of members spanning the bottom-most section of the truss.
top chord
the line of members spanning the top-most section of the truss.
Fatigue
the loss of the load-bearing ability of a material under repeated load application
method of joints
the mathematical procedure for determining the forces acting on every member of a truss, given a certain load.
Reliability
the probability that a component part or system will perform its intended function under given circumstances for a specific period of time
Factor of Safety
the ratio of actual strength to required strength
Modulus of Elasticity
the ratio of stress to strain; E
Hooke's Law
the stress of a solid is directly proportional to the strain applied to it
Breaking Stress
the stress required to fracture a material
dead load
the weight of the bridge itself
live load
the weight of the traffic on the bridge
cables
thick rope or wire
suspension bridge
towers and deck suspended by cables
truss
triangular shape with framework
bridge
used to span the distance over a variety of obstacles and relies upon the forces of compression/ tension
Compression
when a material is reduced in volume by the application of pressure