PSI - Issue 17

Kristýna Čápová et al. / Procedia Structural Integrity 17 (2019) 726 – 733 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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area 1 is valid for chamber A, areas 1 – 3 are valid for chamber B).

Table 1. Parameters of climate chambers.

Chamber A 0 – 90 °C 0,5 K/min 0,2 K/min

Chamber B -42 – 180 °C

Temperature range

Temperature change rate – heating Temperature change rate – cooling

4,0 K/min 3,0 K/min

Humidity

Area 1 in Fig. 2

Area 1+2+3 in Fig. 2

With respect to the known sensitivity of optoelectronic components to temperature and humidity changes, it is necessary to define the parameters of the test cycle in order to prevent the essential components to be tested out of the manufacturer’s defined t emperature and humidity operating range. Due to the technical concept of FBG interrogators developed and manufactured by the research team (Safibra, s.r.o.), it is necessary to analyse not only components of optoelectronics but also computer hardware. The available temperature and humidity ranges for selected components and units are listed in Table 2 and Table 3.

Table 2. Temperature ranges of used PC hardware.

Operating temperature range

Storage temperature range

Motherboard SuperMicro MBD 0 – 60 °C

NA

0 – 70 °C 0 – 85 °C

-40 – 85 °C -55 – 100 °C

SSD Kingston

Operation memory Kingston

-20 – 85 °C (humidity 10 – 90 %, not condensed)

-40 – 65 °C (humidity 5 – 90 %, not condensed)

Power supply

Table 3. Temperature ranges of used optoelectronics.

Operating temperature range Storage temperature range

Temperature drift 1 (3 max) pm / °C

0 – 70 °C (not condensed)

-20 – 70 °C

Spectrometer Ibsen Photonics

2.2. First phase of testing in 2016 In the first phase of the climatic tests, two optoelectronic interrogators (see Fig. 2 (a); FBGuard, PeriGuard) with the same basic hardware mounted in a standard instrument box, used by members of the research team from Safibra for interrogator manufacturing, were place in the climatic chamber. The interrogators share essential optoelectronic parts and assemblies. Environmental parameters in the climate chamber (temperature, humidity) were measured using a combined temperature / humidity sensor installed near the interrogator located in the upper level, see Fig. 2 (b). The power cables and sensor connection cables were pulled through the openings in the side wall of the chamber (power cables through the opening on the left side, sensor cables through the opening on the right side). The connection with the sensors in the second climatic chamber was realized by means of an interconnection terminal with optical couplings. Two different groups of sensors were used during the experiment. In the second chamber, standard FBG sensors for SHM of building and transport structures were used (strain sensors, temperature sensors): • athermal_1512: FBG sensor in athermal casing • fbgs_01_1000_1554: L-bracket strain sensor with 1000 mm length (produced by Safibra) • fbgt_01_1000_1552: temperature compensation of strain sensor located in casing at the endpoint of the sensor (produced by Safibra) • Ormocer: bare optical fibre (primary protection material is Ormocer) rolled onto a spool