ANSYS Workbench五种接触类型浅析

Workbench中提供了5种接触类型,单从字面上很难理解这几种接触的区别,下面将帮助中关于这几个接触类型的描述翻译出来,供参考:

  1. Bonded(绑定):这是AWE中关于接触的默认设置。如果接触区域被设置为绑定,不允许面或线间有相对滑动或分离。可以将此区域看做被连接在一起。因为接触长度/面积是保持不变的,所以这种接触可以用作线性求解。如果接触是从数学模型中设定的,程序将填充所有的间隙,忽略所有的初始渗透。

  2. No Separation(不分离):这种接触方式和绑定类似。它只适用于面。不允许接触区域的面分离,但是沿着接触面可以有小的无摩擦滑动。

  3. Frictionless(无摩擦):这种接触类型代表单边接触,即,如果出现分离则法向压力为零。只适用于面接触。因此,根据不同的载荷,模型间可以出现间隙。它是非线性求解,因为在载荷施加过程中接触面积可能会发生改变。假设摩擦系数为零,因此允许自由滑动。使用这种接触方式时,需注意模型约束的定义,防止出现欠约束。程序会给装配体加上弱弹簧,帮助固定模型,以得到合理的解。

  4. Rough(粗糙的):这种接触方式和无摩擦类似。但表现为完全的摩擦接触,即没有相对滑动。只适用于面接触。默认情况下,不自动消除间隙。这种情况相当于接触体间的摩擦系数为无穷大。

  5. Frictional(有摩擦):这种情况下,在发生相对滑动前,两接触面可以通过接触区域传递一定数量的剪应力。有点像胶水。模型在滑动发生前定义一个等效的剪应力,作为接触压力的一部分。一旦剪应力超过此值,两面将发生相对滑动。只适用于面接触。摩擦系数可以是任意非负值。

以上描述可能有点长,如果难以理解,下面有其他朋友总结的:

Bonded:无相对位移,如同共用节点。

No Separation:法向不分离,切向可以有小位移。

后面三种为非线性接触。

Frictionless:法向可分离,但不渗透,切向自由滑动。

Rough:法向可分离,不渗透,切向不滑动。

Frictional:法向可分离,不渗透,切向滑动,有摩擦力。

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默认 最新
最后附上ANSYS Help中的原文,这是最权威的解释啦: The differences in the contact settings determine how the contacting bodies can move relative to one another. This is the most common setting and has the most impact on what other settings are available. Most of these types only apply to contact regions made up of faces only. Bonded: This is the default configuration and applies to all contact regions (surfaces, solids, lines, faces, edges). If contact regions are bonded, then no sliding or separation between faces or edges is allowed. Think of the region as glued. This type of contact allows for a linear solution since the contact length/area will not change during the application of the load. If contact is determined on the mathematical model, any gaps will be closed and any initial penetration will be ignored. No Separation: This contact setting is similar to the bonded case. It only applies to regions of faces (for 3-D solids) or edges (for 2-D plates). Separation of faces in contact is not allowed, but small amounts of frictionless sliding can occur along contact faces. [Not supported for Explicit Dynamics analyses.] Frictionless: This setting models standard unilateral contact; that is, normal pressure equals zero if separation occurs. It only applies to regions of faces (for 3-D solids) or edges (for 2-D plates). Thus gaps can form in the model between bodies depending on the loading. This solution is nonlinear because the area of contact may change as the load is applied. A zero coefficient of friction is assumed, thus allowing free sliding. The model should be well constrained when using this contact setting. Weak springs are added to the assembly to help stabilize the model in order to achieve a reasonable solution. Rough: Similar to the frictionless setting, this setting models perfectly rough frictional contact where there is no sliding. It only applies to regions of faces (for 3-D solids) or edges (for 2-D plates). By default, no automatic closing of gaps is performed. This case corresponds to an infinite friction coefficient between the contacting bodies. [Not supported for Explicit Dynamics analyses.] Frictional: In this setting, two contacting faces can carry shear stresses up to a certain magnitude across their interface before they start sliding relative to each other. It only applies to regions of faces. This state is known as "sticking." The model defines an equivalent shear stress at which sliding on the face begins as a fraction of the contact pressure. Once the shear stress is exceeded, the two faces will slide relative to each other. The coefficient of friction can be any non-negative value. Choosing the appropriate contact type depends on the type of problem you are trying to solve. If modeling the ability of bodies to separate or open slightly is important and/or obtaining the stresses very near a contact interface is important, consider using one of the nonlinear contact types (Frictionless, Rough, Frictional), which can model gaps and more accurately model the true area of contact. However, using these contact types usually results in longer solution times and can have possible convergence problems due to the contact nonlinearity. If convergence problems arise or if determining the exact area of contact is critical, consider using a finer mesh (using the Sizing control) on the contact faces or edges.
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