Strength and fatigue calculations cockpit seat aircraft pilots of general purpose transport category aircraft
The purpose of the calculations : the analysis of the stress-strain states designs chairs under static and dynamic loads.
List of normative documents.
1. SAEAS8049a «Technical general purpose performance requirements chairs civil helicopters, airplanes and transport category aircraft."
SAE - Society of US self-propelled Transport Engineers (SAE- SocietyofAutomotiveEngineers, Inc.).
AS - AviatsionnyystandartSShA (AS - Aerospace Standard).
2. FAATSOC127a «standardized specifications. Systems seats helicopters and transport planes, normal and multi-purpose category "
FAA - US Federal Aviation Administration (FAA- Federal Aviation Administration).
TSO - Technical Standard Order (TSO- Technical Standard Order).
Material security elements in the designs of seats.
1. Aluminum alloy D16T.
2. Steel alloy 30KhGSA.
- modulus of elasticity = 71 000 MPa;
- Poisson's ratio = 0.34;
- density = 2700 kg / m 3 ;
- yield strength = 325 MPa;
- tensile strength = 450 MPa.
- modulus = 210,000 MPa;
- Poisson's ratio = 0.3;
- density = 7850 kg / m 3 ;
- yield strength = 835 MPa;
- tensile strength = 1080 MPa.
Structural load circuit on the system "+ man chair."
- Pressures on the seat of the pilot efforts by the controls of the aircraft.
- Operating load.
- Loadings auxiliary chair design (armrests, the headrest).
- Static overload during the crash landing of the aircraft.
- Dynamic overload during the crash landing of the aircraft.
In addition analysis of stress-deformed state estimated further:
- strength fasteners seats to the aircraft structure;
- the strength of fastening means fixing the upper and lower portions of human body to the seat.
Overload acting on the person as a concentrated mass system: (F h = nm h g).
Overload acting on the seat, as a system with distributed mass: (F = n (m k1 + m k2 + ... + m to i ) g).
Summary: F = n (m h + m in ) g.
n- overload factor;
g - acceleration of gravity;
m h - Pilot weight 80 kg .;
m h - weight of the operator 77 kg .;
m to - pilot seat weight 30 kg.
m to - weight 25 kg operator seat.