8/3/2019 Soar to New Heights C2R Spring-Summer

1/3www.altair.com/c2Concept To Reality Spring/Summer 2009Concept To Reality Spring/Summer 2009 4 www.altair.com/c2

T

he next time you enter an airplane, check out the interior. The key compo-

nent is the seating package.

With a focus on attracting customers and competing in tight economic

times, more airlines are promoting seat size, ergonomic design and value-

added features as part of their marketing strategy.Their seats must not only appeal to passengers but also adhere to various certification

and safety regulations, including those related to crash impact.

French aircraft seat manufacturer Sicma Aero Seat SA, a subsidiary of Zodiac SA,

closely collaborates with airlines and aircraft manufacturers in the custom design

of airplane, pilot, helicopter and cabin attendant seats. We develop products to our

customers specifications and use a combination of virtual and physical testing to meet

appropriate regulations. In fact, we are increasing the amount of virtual testing we

perform to improve our seating products, cut certification costs and reduce our product

development and delivery cycles.

French manufacturer Sicma Aero Seat SA

relies on virtual dynamic testing in the

evaluation of its custom aircraft seats.

byJeremy Cailleteau

Airline Seat Testing

SoarstoNew Heights

8/3/2019 Soar to New Heights C2R Spring-Summer

2/3www.altair.com/c2r Concept To Reality Spring/Summer 2009

D E S I G N S T R A T E G I E S

5

16 g impact analysis simulating an emergency landing

Take a SeatSicma offers customers a standard set of seats as

well as custom-designed seats. For example, whenairlines order economy seats, they typically select a

model from our catalog. We then make modifications

to the seat such as adjusting for comfort or recon-

figuring the size of the TV screen on the backrest

taking into account regulations that are independent

of the airline class.

Business and first-class seats are designed from

scratch and based on customers requirements and

regulations imposed by various government agencies.

Customer specifications for such seats typically

require more strength to ensure the comfort of

passengers. Product development time for new seats

is very short, about one year from concept to delivery.

There are essentially three phases in our evalu-

ation process. At Sicma Aero Seat, we develop an

initial prototype for new seats to ensure that it meets

customers specifications. Then, we conduct virtual

and physical tests. Finally, we address certification

requirements on the pre-series seats. Depending on

test results, simulations are performed to quickly eval-

uate design modifications to achieve certification.

Safety FirstUnless airline seats pass government regulations,

they cannot be installed on the aircraft. Seats mustbe designed for the safety of passengers and their

rescue. To address safety concerns, we conduct static

and dynamic tests, some of which include passenger

dummies.

For example, to evaluate the strength of the seat

legs and their connection to the floor, we perform

virtual static tests, applying gravity load cases. Virtual

body blocks, which are rigid body representations

of a passenger sitting in the seat, are secured on the

basic seat frame, and static loads are applied in the

up, down, fore and aft directions. The 3D results are

then reviewed to ensure that the seat base frameremains intact to facilitate rescue efforts.

One dynamic test that we perform relates to floor

deformation in emergency landing conditions. Here,

the structure of the seat needs to resist impact. In this

scenario, we apply a sudden deceleration of 16 g to

a seat and dummy, which are moving at a given

velocity. To design for the worst-case scenario, we

deliberately deform the floor before the application

of the deceleration taking into account a pre-

existing damage situation. Failure is not allowed.

The lumbar test is an important dynamic evalu-

ation that measures seat sturdiness. Criteria include

velocity, seat pitch angle, seat yaw angle, peak

deceleration, time-to-peak and floor deformation.

We apply a 60-degree angle load to the floor

(representing the load in an emergency landing

without wheels) as well as a deceleration equal

to 14 g. To pass this test, the measured load in a

passengers lumbar area cannot exceed 1,500 lbs.

In addition, we conduct physical tests to minimize

passenger head injuries. With one dummy placed in

a seat, and another seat positioned in front of the

first, we apply a deceleration of 16 g. During decel-

eration, we want to check the head injuries for the

dummy in the back seat. The seats are designed toavoid passenger impact with sharp or hard objects as

well as to prevent seat deformations that can block

evacuation.

Simulating Real-Word PerformanceEight years ago, all of our seat testing was physical.

Initially, we started to use CAE software to simulate

some static tests on seats, such as passenger push/

pull loads on backrests and armrests. Over time, we

8/3/2019 Soar to New Heights C2R Spring-Summer

3/3www.altair.com/c2Concept To Reality Spring/Summer 2009

For more information about Sicma and RADIOSS, visit

www.altair.com/c2ror check 01 or 02 on the reply card.

D E S I G N S T R A T E G I E S

6

continued to increase and broaden our use of simulation.

A little less than a year ago, we expanded into simulatingdynamic events. Today, we primarily employ simulation

to redesign the seats when the physical tests fall short

of safety government regulations.

The true value of simulation is that it has reduced

the percentage of seats that initially fail. However,

when a new seat does fail a test, simulation allows us

to find the best solution faster by providing us with

a better understanding of the failure phenomena.

In addition, we can avoid lengthy and costly

prototyping and physical testing processes to evaluate

design alternatives.

Altair HyperWorks is the simulation platform that

we predominantly use for our static and dynamic seat

analyses. For example, we use Altair HyperMesh to

support all of our finite element (FE) meshing activities

and HyperView to visualize FE and multi-body systems

results, video and engineering data. For our dynamic

analyses, we use Altairs HyperCrash pre-processing

technology to quickly execute our crash and safety

modeling tasks.

We also use Altairs RADIOSS solver for static and

dynamic simulation and optimization. An advantage

of selecting RADIOSS is that it has tightly integrated

and accurate dummy models to support our safetyevaluations. Further, we were able to customize

Altairs HII_FAA RADIOSS dummy by introducing

some deformable entities and connections to aid

in our testing and evaluation efforts.

We believe that we have a distinct advantage over

our competition by using HyperWorks. The quality

of the CAE tools, the value-based software licensing

model and Altairs technical customer support are

key differentiators over other software providers.

Sicma sees simulation as an important aspect of

our business and for customers. We have an

aggressive pass rate goal for new seat concepts of

90%. By continuing to leverage HyperWorks and

RADIOSS to improve our pass rate, we will eliminate

the need to perform multiple physical tests and

rework. This, in turn, will reduce development costs

and time for both Sicma and our customers.

Jeremy Cailleteau is the Senior FEA Stress Analyst atSicma Aero Seat SA, France.

S

icma Aero Seat SA operates as a subsidiary of

Zodiac SA, a French company that has been in

business since 1909. Sicma is headquartered inFrance with operations in Germany, Brazil, Dubai, Hong Kong

and the United States.

The company is well-known for the manufacture of airline

passenger seats, convertible passenger seats, passenger

seats for low-cost companies, crew and pilot seats, and

helicopter seats. It counts the worlds premier airlines as

well as Airbus and Boeing among its customers.

The company offers new generations of competitive,

16 g-compliant seats,

which require cabinet-

equipment materialsto be able to withstand a crash impact 16 times the force of

gravity. This translates into tougher design, manufacturing

and maintenance constraints.

Seats range from the simplest model to the most

sophisticated, incorporating complex electrical and electronic

features, control and accessories. These include head and

leg rests, video screens, electronic games, Internet access

and telephone sets. Whats more, the company is focused

on innovative designs and concepts such as

the 180-degree seat, the bed-seat and the

Sky Lounge.

Sicma participates in the SAE Technical

Committee, SAE Aircraft SEAT, whichaddresses all facets of aircraft seat design,

maintenance and in-service experience.

The group is responsible for aircraft seat

systems design and performance standards

development.

Business seat (left) andeconomy seat (right)

Innovation in Cabin Interiors