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10
Analysis
10.1 Introduction
Analysis is one of the most fruitful requirements in computer-aided design
(CAD) after preparation or in the process of CAD modeling. Analysis can be
dened as extracting and manipulation of the needed data from a CAD model.
Designers need to analyze the model to ensure the conformance of the product
to required standards and needs. It is discussed in the previous chapter that a
CAD model comprises various features. Features might provide the direct shape
of the component. Sometimes, even a material removal feature does not provide
the component shape directly. In those cases, the CAD models are made in steps,
and the nal shape is generated through a sequence of features in order. Thus,
dimensional checking of the model in every stage of the sequence becomes man-
datory to ensure the nal produced shape being generated in the CAD model.
Sometimes, there must be limitations on the components or product that derives
the model shape. In those cases, the limitations need to be measured and con-
trolled. Mass properties like total weight, center of gravity, and so forth are some
of the major limitations one may have in his/her product.
Dimensions are one of the major criteria that a user needs to know at vari-
ous stages of preparation of a CAD model. CAD provides tools to measure the
dimensions between various entities in a CAD model. A distance between two
noncoplanar and nonintersecting lines is easily measured in CAD, whereas the
same can drive out in-hand calculations with much consumed time and effort.
CAD models are often analyzed for strength and dimension criteria to
ensure and verify the model in the required service condition. A manual
calculation for the strength and stress values of a component may be too
large and time consuming. Finite element analysis (FEA) provides an excel-
lent solution in this type of situation, which enables engineers to validate the
model with comparatively higher accuracy and in lesser time.
Kinetic analyses are among the major required analysis elds in CAD. The
various positions of any point of any part in a mechanism can be traced with
respect to variation of location of other parts. Advanced CAD software pro-
vides tools for simulation of mechanisms. Simulation includes the visualiza-
tion of mechanisms in the running condition; thus, various positions of the
374 Computer-Aided Design
parts in the running condition can be traced out easily. It also provides the
simulation of mechanisms and effects of forces at various conditions, which
enables us to identify the effect of forces in the mechanized parts.
In reality, we always do the optimization by analysis in a CAD model.
Optimization can be dened as the process of achieving the goal of limiting
some derived parameters by varying the prespecied parameters with limita-
tions. When we create a CAD model and we check the dimensions, we always
ensure the nal shape by propagating the feature’s dimensions. Thus, we do the
optimization in our mind. CAD provides tools for optimization by selection of
prespecied parameters and goals. CAD also provides the facility to visualize
the optimized parts in various iterative steps and in a graph, which assists the
designers in understanding the variations and limitations of the model.
There are various kinds of analysis of the engineering product. Most use-
ful analyses are covered in this book in accordance with subject importance.
10.2 Dimensional Analysis
Dimensional analysis includes measurement and manipulation of parameters
like distance, angles, length, and so forth of various entities of the CAD model.
These data are required to check and improve the component design.
10.2.1 Measurements
1. Distance: Distance can be measured between various entities with
or without project references. When no project reference is selected,
the minimum distances between the two entities are shown. If the
distance on a projected plane is to be ensured, a project reference is
required. Figure 10.1 shows an example of dimension measurement.
FIGURE 10.1
3-D view of expansion joint.
375Analysis
When two axes are selected for measurement between them, a mini-
mum diagonal dimension is shown. However, when the projected
dimension with the respective front plane is required, the project
reference shall be selected.
Hands-On Exercise, Example 10.1: Linear Distance
Measurement (Software Used: Creo Parametric; Figure 10.1)
LINEAR DISTANCE MEASUREMENT
Steps:
Open the assembly le HINGE_EXPANSION_JOINT from
Chapter 7.
Click on Tree lters, as shown in Figure 10.2.
Check the boxes of features to display in the model tree.
Click OK to close the box of model tree items.
The linear boundary dimension will be measured, as shown in
Figure 10.3.
FIGURE 10.2
Model tree lter.
FIGURE 10.3
An example of maximum distance measurement.

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