1.Title of the invention
Static Strength Test Rig (SSTR) for structural testing of airframes of ship borne aircrafts
2. Field of invention
This invention relates to structural testing of airframe of a ship borne aircraft.
3. Use of invention his invention finds its applicability in testing the static strength of an airframe of a ship borne aircraft. SSTR provided a platform form for accurate simulation of aerodynamic loads encountered by ship borne aircraft including landing, loads arising due to arrestor hook operation on the deck of a ship.
4.Prior art Nil
5.Draw backs of prior art Not applicable
6. Comparison between prior art and present invention
Not applicable
7. Aim of the invention Aim of the invention is to design a test rig for testing airframe of a ship borne aircraft on ground which can accurately simulate the distributed aerodynamic loads encountered by the aircraft during various flight envelopes including landing loads due to landing on a ship deck with the help of arrestor hook.

Summary of the present invention
One of the mandatory requirements for final certification of any aircraft under development is the assessment of the structural integrity of its airframe. A Static Strength Test Rig (SSTR) was designed and developed for testing the airframe of a ship borne aircraft. The test rig was designed and developed for simulating severe landing loads arising out of higher sink rates like 7.1m/S. The test setup layout is shown in Figure-1. STRR was designed with a view to accurately represent loads due to arrestor hook engagement and distributed counter reactions in the longitudinal direction which balance the arrestor hook loads.
Important features of SSTR are, Modularity, accurate representation of distributed and concentrated loads over the entire airframe, rapid load changeover provisions, fully automated and centralized computer control for simulation of aerodynamic loads, computerized high speed data acquisition system, fault diagnosis and fault rectification and integrated balancing for .countering the airframe weights, loading fixtures andioading trees.
SSTR provides a platform for full aircraft structural integrity tests for various flight envelopes. The aerodynamic loads encountered by the aircraft during flight are simulated by in SSTR. Electrohyralic actuators, controlled by a computerized control algorithm, are used for applying aerodynamic loads bn to the airframe.
10.Statement of invention
This invention finds its- applicability in structural testing of static test specimen of a ship borne aircraft.. This invention can be used to simulate loads experienced by the airframe during flight and landing on the deck of a ship. This invention can be used to test the structural integrity of airframes other types of aircrafts provided the dimensions of those aircrafts matches with the test rig dimensions and highest reactions experienced by the rig.
11.Detailed description of invention
The Rig consists of Strong floor which covers area of around 200 square meters over which the overhead super structure is built. The specimen is supported on the Main and Nose Landing gears and suspended through the sling points for balancing the self weight using hydraulic actuators. The Specimen is loaded with 45 servo controlled Hydraulic actuators along with 6 instrumented reaction system to simulate statically determinant structural test condition.
The Aircraft is suspended using 2 servo controlled actuators which will simulate the flight condition on the specimen during testing. Strain Gauges are bonded oyer 1500 places on the specimen from which strain values are recorded during testing of specimen. Deflection Qf the specimen is also monitored during testing, through the displacement sensors, mounted at critical locations along the specimen. Separate reacting rig is installed to react the test loads on the specimen to maintain the equilibrium of the test specimen.
The complexity in loading the aircraft specimens in the rig, demand for multiple direction loading which runs to the order of 80 to 100 tons. Safety of Test Specimen and People working around the rig are taken care of, by incorporating various safety measures built in the rig. Available resources like Hydraulic actuators, test controllers and test data acquisition systems are being optimally used to cater for the complete loading requirements of the test cases. The test rig is developed on the strong floor and the rig can be modified to suit the different aircraft and loading configurations. The Arrestor Hook System is strength tested by an actuator of 50 ton capacity at resultant direction using simple leverage principle to cater higher loads of the order of 75 tons.
Title of the invention: Static Strength Test Rig (SSTR) for structural testing of airframes of ship borne aircrafts
Claims
We Claim that,
1. SSTR can be used for verifying the structural integrity of airframe of ship borne aircrafts.
2. SSTR accurately simulates the loads experienced by the airframe of ship borne aircraft during various types of flight envelopes including landing on the ship deck with the help of arrestor hook.
3. SSTR is a test facility comprising of static strength test rig, computerized electro hydraulic servo system for load application and a data acquisition system for measurement of strain.
4. SSTR can be used for evaluation of life of structural components.