Implementation of an Organic Database Structure for Population-Based Structural Health Monitoring

Abstract

Population-based Structural Health Monitoring (PBSHM) considers grouping multiple structures into a single population, thus allowing additional insight to be gained from SHM feature data as a whole, compared to insights gained for any individual structure. Current data storage methodologies for SHM often operate from a single structure point of view. Different types of data can often be stored in different systems, files, structures and languages. This approach means that bespoke methodologies must be developed for any new SHM application, making analysing and processing of SHM data costly. The advantage of the proposed unified approach is the facilitation of information sharing across populations of structures, a key principle in PBSHM. A generic pool of methodologies can then be developed, allowing any set of PBSHM data to be quickly and efficiently analysed and processed, bringing down the total cost of running a system.

In this paper a PBSHM schema is defined to store multiple populations of PBSHM data inside a NoSQL database via a Time First approach. The schema allows a single database that organically grows as more data/knowledge about the population becomes available. As everything is grouped by Time, the approach allows previously unknown data relationships to be easily viewed. In this paper the PBSHM schema is implemented in a MongoDB database and sensor data are added into the system to show the ease of use of a standardised data schema.

Appendices

Appendix 1: Non-organic Basic Schema

Please note that the example below uses the MongoDB bsonType instead of the JSON

Appendix 2: Organic Basic Schema

Please note that the example below uses the MongoDB bsonType instead of the JSON

Appendix 3: Accepted Channel Objects Within the v1.0 Schema

Types	Units	Values
acceleration	m/s 2, g, v, other	int, double, object
velocity	m/s, v, other	int, double, object
displacement	mm, cm, m, km, other	int, double, object
angularAcceleration	degrees/s 2, radians/s 2, other	int, double, object
angularVelocity	degrees/s, radians/s, other	int, double, object
angularDisplacement	degrees, radians, other	int, double, object
tilt	degrees, radians, other	int, double, object
strain	nd, other	int, double, object
tension	fN, pN, nN, μN, mN, cN, dN, N, daN, hN, kN, MN, GN, TN, PN, other	int, double, object
load	fN, pN, nN, μN, mN, cN, dN, N, daN, hN, kN, MN, GN, TN, PN, other	int, double, object
structuralPotentialHydrogen	pH, other	int, double, object
temperature	C, F, K, other	int, double, object
humidity	%, other	int, double, object
speed	mph, ft/s, km/h, m/s, kn, other	int, double, object
direction	degrees, radians, other	int, double, object
pressure	fPa, pPa, nPa, μPa, mPa, cPa, dPa, Pa, daPa, hPa, kPa, MPa, GPa, TPa, PPa, at, atm, bar, psi, other	int, double, object
altitude	mm, cm, m, km, feet, other	int, double, object
pitch	degrees, radians, other	int, double, object
yaw	degrees, radians, other	int, double, object
roll	degrees, radians, other	int, double, object
pitchRate	degrees/s, radians/s, other	int, double, object
yawRate	degrees/s, radians/s, other	int, double, object
rollRate	degrees/s, radians/s, other	int, double, object
current	fA, pA, nA, μA, mA, cA, dA, A, daA, hA, kA, MA, GA, TA, PA, other	int, double, object
charge	fC, pC, nC, μC, mC, cC, dC, C, daC, hC, kC, MC, GC, TC, PC, other	int, double, object
power	fW, pW, nW, μW, mW, cW, dW, W, daW, hW, kW, MW, GW, TW, PW, other	int, double, object
voltage	fV, pV, nV, μV, mV, cV, dV, V, daV, hV, kV, MV, GV, TV, PV, other	int, double, object
resistance	fΩ, pΩ, nΩ, μ Ω, mΩ, cΩ, dΩ, Ω, daΩ, hΩ, kΩ, MΩ, GΩ, TΩ, PΩ, other	int, double, object
capacitance	fF, pF, nF, μF, mF, cF, dF, F, daF, hF, kF, MF, GF, TF, PF, other	int, double, object
inductance	fH, pH, nH, μH, mH, cH, dH, H, daH, hH, kH, MH, GH, TH, PH, other	int, double, object
frequency	fHz, pHz, nHz, μHz, mHz, cHz, dHz, Hz, daHz, hHz, kHz, MHz, GHz, THz, PHz, other	int, double, object
conductance	fS, pS, nS, μS, mS, cS, dS, S, daS, hS, kS, MS, GS, TS, PS, other	int, double, object
magneticFlux	fWb, pWb, nWb, μWb, mWb, cWb, dWb, Wb, daWb, hWb, kWb, MWb, GWb, TWb, PWb, other	int, double, object
magneticFieldStrength	fT, pT, nT, μT, mT, cT, dT, T, daT, hT, kT, MT, GT, TT, PT, other	int, double, object
integer	n/a	int
double	n/a	double
text	n/a	string
date	n/a	long

Appendix 4: PBSHM Schema Installation

An example python script for installing the PBSHM Schema into a collection.

Appendix 5: Single vs Multiple File Channel Data

A JSON example showing equal Channel Data on a single file vs multiple files.

Appendix 6: PBSHM Database Querying

An example python script for querying the PBSHM Database.