Indutch Composites Inspection Equipment List
Laser Tracker – Faro Vantage S
|Accuracy (MPE)||95μm + 5μm/m with 50mm stylus length (0.0037in + 0.00006in/ft with 1.97in stylus length) Maximum Permissible Error (MPE) is per ISO 10360-10:2016, reported as the radius of the minimum circumscribing sphere.
|Range||2.5m to 15m (8.20ft to 49.21ft)
|Data Output Rate||1,000 measurement points per second
|Battery Life||2-4 hours for continuous use, typical 8+ hours•
Differential Scanning Calorimeter – DSC 3
|Temperature range||150 to 700 °C|
|Sensor||FRS 5+ with 56 thermocouples or HSS 8+ with 120 thermocouples|
|Heating rate||0.02 to 300 K/min|
|TAWN resolution (FRS /HSS)||0.12/0.2|
|TAWN sensitivity (FRS /HSS)||11.9/56|
|Indium response ratio (FRS sensor)||>155 mW/°C|
Visual Testing is used to find slight markings, paint scrapes, surface blemishes, delamination, and trapped air.
A tap on the composite part produces a clear, sharp tone to a dull thud. By repeated tapping over an area, the points where the tone changes occur are located. These points are usually a disband or delamination.
An Ultrasonic Testing (UT) instrument typically includes a pulse/ receiver unit and a display device. The pulse unit has a transducer probe that converts an electrical signal into a high-frequency sound wave sent into the structure for testing. The defects in the structure cause density changes which reflect the sound waves to the probe, which are then converted to electrical signals and displayed. Inspection data are shown as:
A-scan – Time based waveform display
B-scan – Distance vs. Time graph
C-scan – Plan view Grayscale
Pulse-Echo – One transducer generates and receives the sound wave. Limited to detecting the first occurring defect but better at identifying the depth of the defect and thin film inclusions in composites.
Through-Transmission – Uses two transducers to generate and receive the sound waves. Less sensitive to small defects compared to pulse echo, cannot detect the depth of the defect but better at detecting abnormalities in multi-layered structures.
Phased Array – Dramatically reduces the time required for inspection while providing excellent detection of the smallest defects with their depth. Error detection is done using an array of multiple transducers aligned in a single housing. The transducer array is controlled electronically and is programmed to sweep across the composite part.
A stream of electrons is directed through a test specimen and are sensed on the other side by a detection device. X-Ray inspection is better for fiberglass and aramid fiber composites than with carbon fiber because carbon fiber and conventional matrix resins have deficient X-Ray absorption properties. X-Ray is mainly used to detect transverse cracks, inclusions, honeycomb core damage, and moisture ingression.
A heat source is used to heat the composite part for inspection, and as the part cools down, an infrared camera monitors the part using digital processing equipment. Thermal imaging is useful for detecting disbands, delamination, inclusions, and variations in thickness and density over large areas.
Shearography non-destructive testing uses an image-shearing interferometer to detect and measure local out-of-plane deformation on the test part surface in response to a change in the applied engineered load. Shearography images show only the local distortion on the target surface due to the presence of surface defects subsurface flaws, delaminations, core damage, core splice joint separations, and impact damage.
Destructive Coupon Testing
Indutch Composites uses the standard methods for testing composites developed by the American Society of Testing and Materials (ASTM) and the International Standards Organization (ISO). The testing done at Indutch will represent the composite structure throughout its operational life with all the environmental conditions in consideration. The mechanical property data for composites tests six categories: Tensile, Compressive, Shear, Flexure, Fracture Toughness, and Fatigue.
Typical Composite Material Test Matrix
|Laminate Mechanical Test||Test Method|
|0° Tension||ASTM D3039|
|90° Tension||ASTM D5450|
|0° Compression||ASTM D3410|
|90° Compression||ASTM D5449|
|In-plane Shear||ASTM D3518|
|Interlaminar Shear||ASTM D5379|
Resin, Fiber and Void Content
Matrix Ignition Loss
The test methods ASTM D2584 and ASTM D3171 use a pre-dried and weighted composite specimen, placed in a crucible of known weight. The organic resin is burned off from the sample inside a furnace. The crucible is cooled and reweighed, and the ignition loss represents the resin content of the composite.
Method I :
The matrix removed by digestion leaves the reinforcement unaffected, thus enabling calculation of the reinforcement/ matrix content/ percent void volume
Method II :
Applicable only to laminate materials of known fiber areal weight and calculates the reinforcement of matrix content as well as the cured ply thickness, based on the measured thickness of the laminate.
Fire, Smoke, and Toxicity (FST) Requirements
The properties commonly tested for FST mass transit applications are ignition times, heat release rates, the heat of combustion, flame spread, smoke density, and smoke toxicity. 14 CFR 25.853a is the vertical burn test, which measures the resistance of composites to flame. 14 CFR 25.853d is the OSU rate of heat release which tests whether the materials flashover which provides information on fire size and growth rate. ASTM E1678 examines toxic gas emissions like carbon dioxide, oxygen, hydrogen cyanide, hydrogen chloride and hydrogen bromide over 30 minutes.
Requirements to pass the Vertical Bunsen Burner Test
|Test||Flame Time (s)||Average Drip Extinguishing Time (s)||Average Burn Length|
|60 seconds||<15||<3||6in (152.4 mm)|
|12 seconds||<15||<5||8in (203.2 mm)|
Requirements to pass the Smoke Density Test
|Total Heat Release within the first 2 minutes||< 65 kW.min/m^2|
|Peak Heat Release||< 65 kW/m^2|
|4-minute Smoke Density (Ds)||< 200|