cohesive单元

Traction-separation-based modeling

The modeling of bonded interfaces in composite materials often involves situations where the

Inter mediate glue material is very thin and for all practical purposes may be considered to be of

zero thickness (see Figure 32.5.1–2).

基于牵引-分离建模

粘结界面的建模、经常涉及到的情况中间胶材料非常薄,实际上可能被认为是零厚度。

The behavior of the interface prior to initiation of damage is often described as linear

elastic in terms of a penalty stiffness that degrades under tensile and/or shearloading but is

unaffected by pure compression.

界面启动之前的行为损害通常被认为是线性的弹性的惩罚刚度,降低拉伸或剪切载荷作用下却不受影响由纯压缩。

You may use the cohesive elements in areas of the model where

you expect cracks to develop.However, the model need not have

any crack to begin with.

你可以用粘性元素的区域模型,你期望裂缝发展。然而,该模型不需要任何裂纹。 In fact, the precise locations (among all areas modeled with cohesive elements)

where cracks initiate, as well as the evolution characteristics of

such cracks, are determined as part of the solution. The cracks are restricted to

propagate along the layer of cohesive elements and will not deflect into the

surrounding material

事实上,(在所有的精确位置领域建模与凝聚力元素),发起、裂缝以及演化的特点

这些裂缝,决心作为解决方案的一部分。沿着层裂缝限制传播凝聚力元素和不会转移到周围的材料

Cohesive elements:

• are used to model adhesives between two components, each of which may be deformable or

rigid;

• are used to model interfacial debonding using a cohesive zone framework;

• are used to model gaskets and/or small adhesive patches;

• can be connected to the adjacent components by sharing nodes, by using mesh tie constraints,

or by

using MPCs type TIE or PIN; and

• may interact with other components via contact for gasket applications.

有凝聚力的元素:

•用于模型两个组件之间的粘合剂,其中每个可能变形或刚性;

•使用模型界面脱胶使用软熔带框架;

•使用模型垫圈和/或小胶布;

•可以连接到相邻组件通过共享节点,通过使用网格领带约束,或通过

使用mpc类型的领带或销;

•可能与其他组件的交互通过接触垫的应用程序

Cohesive elements are used to bond two different components.

Often the cohesive elements completely

degrade in tension and/or shear as a result of the deformation.

Subsequently, the components that are initially bonded together by cohesive elements may come into

contact with each other. Approaches for

modeling this kind of contact include the following:

•有凝聚力的元素用于连接两种不同的组件。通常有凝聚力元素完全

在紧张的降解和/或剪切变形的结果。随后,组件

最初由凝聚力元素结合在一起可以互相接触。的方法

建模这种联系包括以下:

Both Abaqus/Standard and Abaqus/Explicit allow modeling of

progressive damage and failure in

cohesive layers whose response is defined in terms of

traction-separation. By comparison, only

Abaqus/Explicit allows modeling of progressive damage and

failure for cohesive elements modeled

with conventional materials (“Defining the constitutive response

of cohesive elements using a

continuum approach,” Section 32.5.5). Damage of the

traction-separation response is defined within

the same general framework used for conventional materials

(see “Progressive damage and failure,”

Section 24.1.1). This general framework allows thecombination

of several damage mechanisms acting

simultaneously on the same material 有限元分析和有限元分析/标准/显式允许建模和失败的渐进破坏

粘性层的响应traction-separation方面的定义。相比之下,只有

有限元分析/显式允许建模和失败的渐进破坏凝聚力元素建模

与传统材料(“定义本构响应凝聚力元素的使用

连续介质方法,”部分32.5.5)。损坏的traction-separation响应内定义

相同的一般框架用于传统材料(见“进步的伤害和失败,”

24.1.1节)。这个总体框架允许代理相结合的损伤机制

同时在相同的材料

Each failure mechanism consists of three ingredients: a damage

initiation criterion, a damage evolution law, and a choice of

element removal (or deletion) upon reaching a completely

damaged state.

每个失败的机制包括三个成分:伤害初始标准,损伤演化准则,选择单元删除(或删除)到达一个完全破坏状态。

The initial response of the cohesive element is assumed to be

linear as discussed above. However,

once a damage initiation criterion is met, material damage can

occur according to a user-defined damage

evolution law. Figure 32.5.6–1 shows a typical

traction-separation response with a failure mechanism.

If the damage initiation criterion is specified without a

corresponding damage evolution model, Abaqus will evaluate the damage initiation criterion for output purposes

only; there is no effect on the response

of the cohesive element (i.e., no damage will occur). The

cohesive layer does not undergo damage under

pure compression.

内聚的最初反应元素被认为是线性正如上面所讨论的。然而,

一旦遇到伤害启动判据,根据用户定义的物质损失可能发生损伤

进化的法律。图32.5.6-1显示了一个典型的traction-separation响应与破坏机理。

如果指定损伤起始标准没有相应的损伤演化模型,有限元分析

将评估损伤起始标准输出的目的,对反应没有影响吗

(即凝聚力的元素。,没有损害会发生)。粘性层不进行破坏

纯压缩。

As the name implies, damage initiation refers to the beginning of

degradation of the response of a material

point. The process of degradation begins when the stresses

and/or strains satisfy certain damage initiation

criteria that you specify. Several damage initiation criteria are

available and are discussed below. Each

damage initiation criterion also has an output variable