Mechanical performance modeling and failure prediction of Fiber Reinforced Additively Manufactured (FRAM) composites under static, dynamic, cyclic, and long-term loading conditions

为了实现将增材制造复合材料作为功能工程应用的最终用途部件的最终目标，本研究追求以下两个长期目标：1-建立微观力学模型来研究纤维增强增材制造（FRAM）复合材料，旨在了解失效机制，以防止/延迟失效并提高性能。2-建立基于连续损伤力学（CDM）的渐进损伤模型，利用从上述微力学模型中获得的洞察力和信息，预测FRAM复合材料部件在静态、动态、循环和长期加载条件下的失效。本研究旨在提供一种经过实验验证的数值替代方法，以替代一些昂贵且耗时的FRAM复合材料实验。它的目的是特别检查失效机制，以及这些机制是如何受到增材制造参数的影响。本研究的短期目标分解如下：1-开发具有代表性体积单元（RVE）的微观力学模型，该模型可以代表3d打印的纤维增强复合材料，而不是用于传统制造复合材料的RVE。将粘弹性和粘塑性纳入纤维和热塑性基体的本构行为。3-纤维和基体成分材料特性的实验测试程序。4-使用微观力学模型预测3D打印复合材料零件的有效性能。5-利用微观力学模型确定破坏机制以及微观组织与力学性能之间的关系。开发CDM模型来预测3D打印复合材料的失效。对各种3D打印复合材料进行实验测试，并使用测试结果验证所提出的损伤模型。将提出的损伤模型应用到基于商业有限元的软件中。据加拿大航空航天工业协会称，先进复合材料是对加拿大航空航天工业未来具有战略重要性的三大“优先技术”之一。该领域尚未开发的潜力是使用增材制造的复合材料部件。最近的研究表明，增强3D打印的热塑性部件可以大大提高机械性能，从而提高这些部件的功能。考虑到增材制造技术的各种优势，如低成本、生产时间短、材料浪费少，使用3D打印复合材料将是将这些材料用作最终用途、功能性承重部件的重要一步。

Towards the ultimate goal of using additively manufactured composites as end-use parts for functional engineering applications, this research pursues the following two long-term objectives: 1- Develop a micromechanical model to study Fiber Reinforced Additively Manufactured (FRAM) composites aimed at understanding the failure mechanisms in order to prevent/delay failure and enhance performance. 2- Establish a progressive damage model based on Continuum Damage Mechanics (CDM) using the insight and information obtained from the afore-developed micromechanical model to predict the failure of FRAM composite parts under static, dynamic, cyclic, and long-term loading conditions. The research effort seeks to present an experimentally validated numerical substitute for some of the costly and time-consuming experiments on FRAM composite materials. It aims in particular to examine the failure mechanisms and how these mechanisms are influenced by the additive manufacturing parameters. The break-down of the short-term objectives of this study is as follows: 1- Development of a micromechanical model with a Representative Volume Element (RVE) that can represent a 3D-printed fiber reinforced composite as opposed to the RVE used for conventionally manufactured composites. 2- Implementation of viscoelasticity and viscoplasticity into the constitutive behaviour of the fiber and thermoplastic matrix. 3- Experimental test program for material characterization of the fiber and matrix constituents. 4- Using the micromechanical model to predict the effective properties of 3D printed composite parts. 5- Using the micromechanical model to determine failure mechanisms and the correlation between the microstructure and the mechanical properties. 6- Development of a CDM model to predict the failure of 3D printed composites. 7- Experimental test program on various 3D printed composites and using the test results to validate the proposed damage model. 8- Implementation of the proposed damage model into a commercial Finite element- based software. According to the Aerospace Industries Association of Canada, advanced composites are one of three "priority technologies" of strategic importance to the future of the Canadian Aerospace Industry. An untapped potential in this area is the use of additively manufactured composite parts. Recent studies have shown that reinforcing 3D printed thermoplastic components can greatly enhance the mechanical properties and thus the functionality of these parts. Considering the various advantages of the additive manufacturing technology such as low cost, short production time, and minimal waste of material, the use of 3D printed composites will be a great step towards employing these materials as end-use, functional load- bearing components.