A statistical framework proposed for estimating fracture resistance of additively manufactured PLA components considering crack tip plasticity effects

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2025-09-18 DOI:10.1016/j.tafmec.2025.105246

Hossein Ahmadian , Borhen Louhichi , Hadi Sadeghian , Majid R. Ayatollahi

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引用次数: 0

Abstract

This study presents a statistical framework for assessing the fracture behavior of Polylactic Acid (PLA) specimens fabricated using the Fused Filament Fabrication (FFF) technique. Specifically, the model is developed to predict the fracture load of a specimen under predominant bending conditions, based on the tensile properties of the base material and the fracture resistance of a pre-cracked specimen subjected to predominantly tensile loading. To achieve this, tensile tests were first conducted on dogbone specimens, and the corresponding material properties were determined using the Digital Image Correlation (DIC) technique. Fracture tests were then performed on pre-cracked Semi-Circular Bending (SCB) and Single Edge Notched Tension (SENT) specimens to collect the fracture data. These experiments were conducted at two environmental temperatures (−10 °C and 25 °C) to further assess the efficacy of the proposed framework in predicting fracture loads under different levels of plasticity. The results of fracture tests were statistically analyzed using the Weibull model. Fracture mechanics criteria within the Theory of Critical Distances (TCD), especially the Point Method (PM) and the Line Method (LM), were then combined with the Weibull model to predict the fracture loads of target specimens (SCBs). Additionally, the Fictitious Material Concept (FMC) was employed to account for the plastic deformation around the crack tip in the SENT specimens. The results show that the proposed framework provides accurate predictions under both environmental conditions, with maximum discrepancy of 6.3 % at −10 °C and 2.7 % at 25 °C. Beyond the primary objective, this study also investigates the geometry effects on fracture behavior of the tested specimens. This analysis was conducted by examining the fracture surfaces and performing elastic-plastic Finite Element (FE) analyses to compare the size of their plastic zones. The findings from this investigation indicate that SENT specimens exhibited more pronounced plastic deformation compared to SCB counterparts.

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提出了一种考虑裂纹尖端塑性影响的增材制造聚乳酸构件抗断裂性能估算的统计框架

本研究提出了一个统计框架，用于评估使用熔融长丝制造（FFF）技术制造的聚乳酸（PLA）试样的断裂行为。具体来说，该模型的开发是为了预测主要弯曲条件下试样的断裂载荷，基于基材的拉伸性能和预裂试样在主要拉伸载荷下的断裂抗力。为了实现这一目标，首先对狗骨样品进行拉伸试验，并使用数字图像相关（DIC）技术确定相应的材料性能。然后对预开裂的半圆弯曲（SCB）和单边缘缺口拉伸（SENT）试件进行断裂试验，以收集断裂数据。这些实验在两种环境温度（- 10°C和25°C）下进行，以进一步评估所提出的框架在预测不同塑性水平下断裂载荷方面的有效性。断裂试验结果采用Weibull模型进行统计分析。然后将临界距离理论（TCD）中的断裂力学准则，特别是点法（PM）和线法（LM）与Weibull模型相结合，预测目标试件（scb）的断裂载荷。此外，采用虚拟材料概念（FMC）来解释SENT试样中裂纹尖端周围的塑性变形。结果表明，所提出的框架在两种环境条件下都能提供准确的预测，在- 10°C和25°C的最大误差分别为6.3%和2.7%。除了主要目的之外，本研究还研究了几何形状对试件断裂行为的影响。该分析是通过检查断口表面并进行弹塑性有限元（FE）分析来比较其塑性区的大小来进行的。本研究结果表明，与SCB相比，SENT试件表现出更明显的塑性变形。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.