Failure Probability and Safety Gain of Super-Strong Biomimetic Nacreous Materials
Abstract
Major Goals: The basic objective is the mathematical modeling of the failure probability, Pf, with focus on the low probability tail up to one in a million (i.e. <1.E-6), and assessment of safety advantages of the nacreous, biomimetic and similar architected quasibrittle materials. Prior to this grant, there existed only two probability models of material strength - 1) the weakest link chain, or series coupling (leading to Weibull statistics), and 2) the fiber bundle, or parallel coupling (leading to the normal, or Gaussian, distribution). These are nearly identical in the central probability range, but their extrapolations to probability 1.E-6, the maximum tolerable in engineering design, can differ as 2 : 1. The objective has been to model, for the first time, materials exhibiting regular alternations of both parallel and series couplings. This is important for nacreous biomimetic materials whose microstructure network connectivity resembles a fishnet pulled diagonally, and for other similar architected materials such as the printed octet material microstructures, which offers the highest strength-to-weight ratio for a given printing material. Special emphasis is placed on ensuring the failure probability, Pf, to be less than one in a million, which is a degree of reliability generally required of engineering structures, including most of those for Army applications. This objective requires overcoming four main challenges.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 06, 2022
- Accession Number
- AD1221354
Entities
People
- Zdeněk Bažant
Organizations
- Northwestern University