Extreme weight reduction using expanded aluminum mesh

FEA analysis of a structural member

8/31/2016

Don Blanchet

3B Associates

dwb3298@verizon.net

Goals

Reduce the weight of a small but critical motor mount component for a light single person aircraft.

Due to cost limitations a graphite fibrestructure was ruled out.

Trade study of original solid machined design with metal mesh design.

Location of critical component a part of the engine mount assembly

Solid plate design 6061-t6 aluminum

~ 7 x 4 x 0.5 inches Weight = 0.62 lbs

FEA mesh

Fixed boundary conditions

First resonant frequency920 hz

Static stress = 15,750 psi

Oposing 100 lb loads

Elastic twist deformation= .080 inch

Aluminum mesh core design – vacuum brazed

.010 thick expanded metal mesh

.010 thick cover platesBrazed to mesh both sides

Total Weight = 0.23 lbs

FEA mesh with covers

FEA mesh without covers

First resonant frequency= 1329 hz

Static stress = 32,330 psi

Elastic twist deformation= .150 inch

Results summary

Analysiscase

ResonantFrequency

hz

MaximumStress

psi

Maximumelastic

Deflectioninch

Weightlbs

Factor of SafetyYield

strength = 42,000 psi

Solidmachined

plate920 15,750 0.080 0.62 2.7

Expandedaluminum

core1329 32,330 0.150 0.23 1.3

Conclusions

There is a 63% weight savings using the vacuum brazed expanded metal core design.

The stress design margin will be reduced to 30%.

Very critical weight savings can be attained a at reasonable cost increase.