Exam 3 MAE 1351, (EXAM 3) MAE 1351 - UTA, Exam 3 MAE 1351

boundary conditions

constraints and loads added to the boundaries of a finite element model

interference

amount of overlap between two instances in an assembly

clearance

minimum distances between two instances in an assembly

arc

A curved entity that represents a portion of a circle

boundary boxes

A square box used to sketch circles or ellipses

tick mark

A short dash used in sketching to locate points on the paper

right-handed system

Any 3-D coordinate system that is defined by the right hand rule

right-hand rule

Used to define a 3-D coordinate system where by pointing fingers of the right hand down the x-axis and curling them in the direction of the y-axis, the thumb will point down the z-axis

left-handed system

Any 3-D coordinate system that is defined by the left-hand rule.

isometric axes

A set of three coordinate axes that are portrayed on the paper at 120 degrees relative to one another.

isometric dot paper

Paper used for sketching purposes that includes dots located along lines that meet at 120 degrees.

isometric pictorial

A sketch of an object that shows its three dimensions where isometric axes were used as the basis for defining the edges of the object

shading

Marks added to surfaces and features of a sketch to highlight to define 3-D space

isometric line

Lines on an isometric drawing that are parallel or perpendicular to the front, top, or profile viewing planes

axonometric drawing

A drawing in which all three dimensional axes on an object can be seen, with the scaling factor constant in each direction. Usually, one axis is shown as being vertical.

cabinet oblique drawing

An oblique drawing where one half the true length of the depth dimension is measured along the receding axes.

cavalier oblique drawing

An oblique drawing where the true length of the depth dimension is measured along the receding axes.

vanishing point (vp)

In the construction of a perspective view, the point on the horizon where all parallel lines in a single direction converge.

plan view

In the construction of a perspective view, the object as viewed from the top, as if created by orthogonal projection.

station point (sp)

In the construction of a perspective view, the theoretical location of the observer who looks at the object through the picture plane.

picture plane (pp)

In the construction of a perspective view, the viewing plane through which the object is seen. The PP appears as a line (edge view of the viewing plane) in the plan view

measuring line (ml)

In the construction of a perspective view, a vertical line used in conjunction with the elevation view to locate vertical points on the perspective drawing.

measuring walls

In the construction of a perspective view, a line that extends from the object to the vanishing point to help establish the location of horizontal points on the drawing

perspective drawing

A drawing in which all three-dimensional axes on an object can be seen, with the scaling factor linearly increasing or decreasing in each direction. Usually one axis is shown as being vertical. This type of drawing offers the most realistic presentation of an object.

pictorial

A drawing that shows the 3-D aspects and features of an object.

trimetric drawing

An axonometric drawing in which the scaling factor is different for all three axes.

center-of-mass (centroid):

The origin of the

coordinate axes for which the first moments are zero.

reverse engineering

: A systematic methodology for

analyzing the design of an existing device.

What are some of the mass properties that can be

computed for a CAD model?

Density, Mass, Volume, Surface area, Center-of-mass or centroid, principle aces-of-inertia and principle moments-of0inertia, radius-of-gyration

Is it easier to spin a

wheel with a large diameter or a small diameter?

a wheel with a large diameter will be harder to accelerate

to a desired rotation rate than a wheel with a small diameter. so its easier to spin a wheel with a small diameter

What kinds of boundary conditions can be applied

to a finite element model?

stress analysis - forces or defined displacements

thermal analysis - input temperature.

objects subjected to external

forces, you must fix some of the nodal points in space so the object is not able to move

at those points.

In general, will accuracy

improve as element size gets smaller or as it gets

larger?

yes it will improve however error can appear if it is too small

Measure Point

This command returns the coordinates (x-, y-, and z-) of a specific

point on a sketch or model. Usually, this point has to be a pickable point, such as

a corner or circle center

Measure Line Length

This measure command returns the length of a line (it can be from a point to another point)

Measure Line Distance

This measure command returns the shortest (perpendicular)

distance between a line and another identified entity, such as a point

Measure Circle

This measure command returns the center and diameter of a circle,

such as a hole diameter

Measure Arc

The Measure Arc command returns the center and radius of an arc

Measure Surface

Measure Surface returns the area of a specified surface and the

length of the perimeter surrounding that surface.

What are the two things mass properties depend on?

The geometry of the part and its density

What is a common place where you need to check interferences and clearances?

between shafts and circular holes

bounding box

A square box used to sketch circles or

ellipses.

sketch line

from top to bottom

Isometric pictorial

shows the 3 planes and can be : 120 degrees all around or 2 60 deg and one 240 degrees

Oblique pictorial

the three dimensions of the object are shown, two (height and width) must be at a 90 degrees angle and last (depth) receding off at an angle

Advantage of Oblique over Isometric

when one face of the object is placed in the plane of the paper, the object will appear in its

true shape and size in that plane—it will be undistorted

Diametric view

two of the three visible surfaces have angles equal to each other and not equal to 120

Trimetric view

all angles are different :)

Are orthographic views considered formal?

no, they are informal therefore you would not use them for a formal engineering design unless used for design clarification/ reference

Disadvantage of oblique pictorials

they tend to be distorted and appear elongated when viewed because they are not a "true projection"

Advantage of Oblique pictorials

one surface appears as its true size and shape and its not distorted

What are the two types of Oblique Drawings

Cavalier and Cabinet

difference between cavalier and cabinet

the difference lies in the measurement made along the receding depth axes

Perspective drawings and sketches

are some of the most lifelike pictorials created

Why is two point perspective drawing better?

the one and three point perspective are limited in their use and do not convey an image that the eye would be likely to perceive

center of mass

origin of the coordinate axes for which the moments are zero

displacements

change in the location of points on an object after it has been subjected to external loads

constraints

boundary condition applied to a finite element model to prevent it from moving through space

line

Shortest distance between two points

circle

A closed curved figure where all points on it are equidistant from its center point

ellipse

A closed curved figure where the sum of the distance between any point on the figure and its two foci is constant

3-d coordinate system

A set of mutually perpendicular axes used to define 3-D space

isometric grid paper

Paper used for sketching purposes that includes grid lines at 120 degrees relative to one another

oblique pictorial

A sketch of an object that shows one face in the plane of the paper and the third dimension receding off at an angle relative to the face

oblique axes

A set of three coordinate axes that are portrayed on the paper as two perpendicular lines, with the third axis meeting them at an angle, typically 45 degrees

receding dimension

The portion of the object that appears to go back from the plane of the paper in an oblique pictorial.

construction line

A faint line used in sketching to align items and define shapes

elevation view

In the construction of a perspective view, the object as viewed from the front, as if created by orthogonal projection

horizontal line (hl)

In the construction of a perspective view, the line represents the horizon, which is the separation between the earth and the sky at a long distance. The left and right vanishing points are located on the HL. The PP and the HL are usually parallel to each other.

ground line (gl)

In the construction of a perspective view, a line on the elevation view that represents the height of the ground.

diametric drawing

An axonometric drawing in which the scaling factor is the same for two of the axes