Mechanical Technology

Mechanical Technology — July 2015

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Computer-aided engineering

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While developers will typically start with

CAD, then go to engineering analysis

based on the 3D CAD model and then

onto manufacturing, we advise a process

change involving these three questions

being addressed in advance of CAD.

On the material side, composites,

aluminium or titanium are typically used

as substitute options in lightweighting ex-

ercises. Any change in material, however,

must come with an associated change

in the topology of the new component.

“The cornerstone of solidThinking

Inspire involves automatic topology

optimisation,” Smith says, opening the

software to display how solidThinking

works. “At its starting point, a part is

sketched using primitive solids (cubes,

cylinders, etc.), or an existing part can

be imported and de-featured to define the

design space. Then the fasteners, joints

and boundary contact points are defined,

before the required materials and external

structural loads are assigned.”

Once the basic shape, engineering

materials and specifications have been

assigned, solidThinking begins to gener-

ate an ideal shape. “Embedded in the

analysis tools are bio-mimicry philoso-

phies. Bones grow stronger along load-

paths where they need to. In the same

way, the geometry of a part can have

ribs, struts or thickening added where it

is needed and removed where it is not

needed. The topology of the part can,

therefore be quickly and automatically

established before doing any detailed

design,” he reiterates.

Once complete, the part performance

is verified before the resulting geometry

is smoothed using Evolve, the free-form

design software from solidThinking, or

the geometry can be exported into a CAD

package for refinement and integration.

Evolve makes use of NURBS (non-

uniform rational basis splines) – com-

monly used in computer graphics for

generating and representing curves and

surfaces. “NURBS allows for flexibility

and are widely used in free-form design

and clay modelling tools,” he explains.

Underpinning solidThinking’s optimi-

sation capability is Altair’s OptiStruct

structural optimisation technology which

is available under HyperWorks licens-

ing for more advanced simulation and

analysis, if required.

On the manufacturing side, additional

options allow part topology optimisation

that suits the preferred manufacturing

method. “We are particularly strong on

3D printing or additive manufacturing.

Designs can be exported for pre-3D

print processing to several packages

developed by the major 3D printer manu-

facturers, for example 3-maticSTL from

Materialise,” Smith continues, adding,

“3D part printing allows a high degree

of complexity and flexibility in terms part

geometry”.

But manufacturing shape controls for

processes such as casting, moulding or

stamping are also embedded into the op-

timisation constraints. If being extruded,

for example, solidThinking generates

constant cross-section topologies based

on the extrusion direction.

In spite of the power of the solidThink-

ing Inspire, “the software is very easy to

learn” and it is compatible with existing

CAD tools, such as Creo Parametric.

“Typical training for a design engineer can

be done in a single day,” Smith assures.

Niche successes include: the sup-

porting struts for satellites, a simple

basic design that is then lightweighted

to optimise dynamic performance; the

hinges on aircraft doors, which resulted

in a 64% weight saving; and advanced

bicycle frames.

“Not only is Inspire successful in the

aerospace industry, but also automotive

manufacturers, such as Daimler AG, are

officially certifying solidThinking Inspire

for company wide use,” Smith reports.

With the Daimler certification, all

design engineers within the car and

truck development departments of the

company may now use solidThinking

Inspire within their projects, giving them

an opportunity to create efficient struc-

tures with minimum weight. This works

for components, assemblies, and entire

systems. Design engineers may also use

solidThinking Inspire to apply a required

stiffness on a component where needed,

helping to avoid undesired vibrations and

contributing to overall vehicle comfort

and quality.

Standalone licences of solidThinking

products are available through the lo-

cal channel partners or as tools within

Altair’s HyperWorks suite of simulation

software.

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