Purpose

The purpose of this paper is to study the mechanical property of three-dimensional (3D) Printed photopolymer (Vero Yellow and Tango Black) with different constant strain rate. According to the experimental results, three constitutive models are used to describe the stress-strain and stress-time relation in the tension and stress relaxation process.

Design/methodology/approach

The Stratasys Objet 260 was used to prepare the four groups of samples with different photopolymers (Vero Yellow and Tango Black). The stress-strain and stress-time relations are obtained by the uniaxial tensile tests and relaxation tests performed at room temperature with different constant strain rates. The generalized Kelvin model (GKM), standard linearized model (SLM) and fractional order model (FOM) are used to describe experimental data by means of the curve-fitting approach.

Findings

Experimental results show that the tension stress increases faster at a higher strain-rate for tensile tests. Relaxation stress is influenced by the preload strain-rate for relaxation tests. For the theoretical fitting, the error comparison between three constitutive models and experimental data are calculated to demonstrate the high accuracy in describing the stress-strain relationship for tension. For stress relaxation, the error comparison confirms higher accuracy of FOM with the largest error within 3%, while the error of GKM and SLM up to 10%.

Originality/value

The paper confirms the viscous-elastic mechanical property of 3D printed photopolymer composites (Vero Yellow and Tango Black) for Stratasys PolyJet. As FOM shows high accuracy both in describing stress-strain and stress-time relation for tension and stress relaxation process, it can be directly used as a constitutive model to predict mechanical properties for engineering application.

中文翻译：

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3D打印光敏聚合物的粘弹性力学性能和本构模型

目的

本文的目的是研究具有不同恒定应变率的三维（3D）印刷光敏聚合物（Vero Yellow和Tango Black）的机械性能。根据实验结果，采用三个本构模型来描述拉应力和应力松弛过程中的应力-应变和应力-时间关系。

设计/方法/方法

Stratasys Objet 260用于制备四组具有不同光敏聚合物的样品（Vero Yellow和Tango Black）。应力-应变和应力-时间关系是通过在室温下以不同的恒定应变速率进行的单轴拉伸试验和松弛试验获得的。广义开尔文模型（GKM），标准线性化模型（SLM）和分数阶模型（FOM）通过曲线拟合方法来描述实验数据。

发现

实验结果表明，在拉伸试验中，拉伸应力在较高的应变速率下增加得更快。松弛应力受松弛试验中预紧应变率的影响。为了进行理论拟合，计算了三个本构模型与实验数据之间的误差比较，以证明在描述拉应力-应变关系时具有很高的准确性。为了消除应力，误差比较确认了FOM的准确性较高，最大误差在3％以内，而GKM和SLM的误差高达10％。

创意/价值

该论文证实了Stratasys PolyJet的3D打印光敏聚合物复合材料（维洛黄色和探戈黑）的粘弹性机械性能。由于FOM在描述张力和应力松弛过程的应力-应变和应力-时间关系方面均显示出很高的准确性，因此可以直接用作本构模型来预测机械性能，以用于工程应用。