彈性力學(xué)仿真軟件：MSC Nastran：接觸分析基礎(chǔ)

彈性力學(xué)仿真軟件：MSCNastran：接觸分析基礎(chǔ)1彈性力學(xué)仿真軟件：MSCNastran：接觸分析基礎(chǔ)1.1MSCNastran簡介1.1.11軟件概述MSCNastran是一款由MSCSoftware開發(fā)的高級有限元分析軟件，廣泛應(yīng)用于航空航天、汽車、電子、能源等多個行業(yè)。自1960年代末期為NASA開發(fā)以來，MSCNastran已經(jīng)成為結(jié)構(gòu)分析、動力學(xué)分析、熱分析、優(yōu)化設(shè)計等領(lǐng)域的標(biāo)準(zhǔn)工具。它能夠處理復(fù)雜的工程問題，提供精確的解決方案，幫助工程師在設(shè)計階段預(yù)測和解決潛在的結(jié)構(gòu)問題。1.1.22主要功能與應(yīng)用領(lǐng)域1.1.2.1主要功能結(jié)構(gòu)線性與非線性分析：能夠分析結(jié)構(gòu)在靜態(tài)和動態(tài)載荷下的響應(yīng)，包括線性和非線性材料行為、幾何非線性以及接觸非線性。動力學(xué)分析：包括模態(tài)分析、諧響應(yīng)分析、瞬態(tài)動力學(xué)分析和隨機振動分析，用于預(yù)測結(jié)構(gòu)在不同動力學(xué)環(huán)境下的行為。熱分析：能夠模擬熱傳導(dǎo)、對流和輻射，分析結(jié)構(gòu)的溫度分布和熱應(yīng)力。優(yōu)化設(shè)計：提供結(jié)構(gòu)優(yōu)化功能，包括形狀優(yōu)化、尺寸優(yōu)化和拓撲優(yōu)化，以達到最佳設(shè)計性能。多體動力學(xué)：模擬機械系統(tǒng)中多個剛體和柔體的相互作用，包括碰撞、摩擦和間隙效應(yīng)。1.1.2.2應(yīng)用領(lǐng)域航空航天：用于飛機和航天器的結(jié)構(gòu)分析，確保設(shè)計的安全性和可靠性。汽車工業(yè)：分析車輛的碰撞安全性、振動特性以及疲勞壽命，優(yōu)化設(shè)計以提高性能。電子行業(yè)：模擬電子設(shè)備的熱管理，確保設(shè)備在不同環(huán)境下的正常運行。能源行業(yè)：分析風(fēng)力渦輪機、核反應(yīng)堆等結(jié)構(gòu)的動態(tài)響應(yīng)，確保能源設(shè)施的安全運行。建筑與土木工程：評估建筑物和橋梁在地震、風(fēng)載等自然力作用下的穩(wěn)定性。1.2示例：結(jié)構(gòu)線性分析在MSCNastran中進行結(jié)構(gòu)線性分析，通常涉及定義材料屬性、幾何形狀、邊界條件和載荷。下面是一個簡單的示例，展示如何使用MSCNastran進行梁的線性靜態(tài)分析。$MSCNastran梁的線性靜態(tài)分析示例

$定義單元類型

GRID,1,0.,0.,0.

GRID,2,1.,0.,0.

GRID,3,2.,0.,0.

CBEAM,1,1,2,1,1,0.

CBEAM,2,2,3,1,1,0.

$定義材料屬性

MAT1,1,3.0e7,0.3,0.3e-3

$定義截面屬性

SECTUBE,1,0.1,0.01

$定義邊界條件

SPC,1

1,1,2,3

$定義載荷

FORCE,1

2,1,0.,0.,-1000.

$分析控制

SUBCASE,1

SOL,101

METHOD,1

EIGRL,1,1,1,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,

#彈性力學(xué)仿真軟件：MSCNastran：接觸分析基礎(chǔ)

##二、接觸分析理論基礎(chǔ)

###2.1接觸力學(xué)基本概念

在彈性力學(xué)仿真中，接觸分析是模擬兩個或多個物體在接觸界面處相互作用的關(guān)鍵技術(shù)。接觸力學(xué)主要研究接觸面上的力、位移、壓力分布等現(xiàn)象。在MSCNastran中，接觸分析通過定義接觸對（一對主面和從面）來實現(xiàn)，其中主面（MasterSurface）和從面（SlaveSurface）的概念至關(guān)重要。

-**主面（MasterSurface）**：在接觸對中，主面定義了接觸的幾何形狀和位置，通常選擇較為光滑或復(fù)雜的表面作為主面。

-**從面（SlaveSurface）**：從面則是在接觸過程中可能與主面接觸的表面，從面上的節(jié)點會遵循主面上的位移。

####示例：定義接觸對

在MSCNastran中，定義接觸對通常通過輸入卡（InputCards）來實現(xiàn)。以下是一個簡單的接觸對定義示例：

```nastran

BEGINBULK

$Definethemastersurface

SPLINE,1,1001,1002,1003,1004

$Definetheslavesurface

SPLINE,2,2001,2002,2003,2004

$Definethecontactpair

CONTACT,1,1,2在這個例子中，SPLINE卡用于定義主面和從面，CONTACT卡則用于定義接觸對，其中1是接觸對的標(biāo)識，1和2分別為主面和從面的標(biāo)識。1.2.12接觸分析類型MSCNastran支持多種接觸分析類型，包括：線性接觸：假設(shè)接觸力與位移成線性關(guān)系，適用于小變形和小位移的情況。非線性接觸：考慮接觸力與位移的非線性關(guān)系，適用于大變形和大位移的情況。自接觸：模擬同一模型內(nèi)部不同部分之間的接觸，例如折疊或纏繞的結(jié)構(gòu)。多體接觸：模擬多個獨立物體之間的接觸，例如齒輪嚙合或球軸承分析。1.2.1.1示例：非線性接觸分析在進行非線性接觸分析時，需要在MSCNastran中指定非線性接觸屬性。以下是一個非線性接觸屬性的定義示例：BEGINBULK

$Definenonlinearcontactproperty

CPLSTN,1,1,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,

#三、MSCNastran接觸分析設(shè)置

##3.1接觸對定義

在MSCNastran中，接觸對的定義是接觸分析的基礎(chǔ)。接觸對由兩個部分組成：主面（MasterSurface）和從面（SlaveSurface）。主面通常是指不會發(fā)生大的變形的表面，而從面則是可能與主面接觸并發(fā)生變形的表面。

###定義接觸對

接觸對可以通過以下方式定義：

-**使用GRID和CTRIA3/CTETRA單元**：GRID單元代表節(jié)點，CTRIA3和CTETRA單元代表表面。在接觸分析中，GRID單元可以與CTRIA3或CTETRA單元形成接觸對。

-**使用SOLID和SHELL單元**：SOLID單元通常作為主面，而SHELL單元作為從面，形成接觸對。

###示例

假設(shè)我們有兩個實體，一個由SOLID單元組成，另一個由SHELL單元組成。我們想要定義它們之間的接觸對。

```nastran

BEGINBULK

$Definethesolidentity

SOLID,1,1001,1002,1003,1004,1005,1006

GRID,1001,0.0,0.0,0.0

GRID,1002,1.0,0.0,0.0

GRID,1003,1.0,1.0,0.0

GRID,1004,0.0,1.0,0.0

GRID,1005,0.0,0.0,1.0

GRID,1006,1.0,0.0,1.0

$Definetheshellentity

SHELL,1,2001,2002,2003

GRID,2001,2.0,0.0,0.0

GRID,2002,3.0,0.0,0.0

GRID,2003,3.0,1.0,0.0

$Definethecontactpair

CPAIR,1,1,2,1,1在這個例子中，SOLID單元（由GRID1001-1006組成）被定義為主面，而SHELL單元（由GRID2001-2003組成）被定義為從面。CPAIR卡定義了接觸對，其中1是接觸對的ID，1是主面的ID，2是從面的ID，1是接觸屬性的ID，1是接觸控制參數(shù)的ID。1.32接觸屬性設(shè)置接觸屬性定義了接觸對之間的相互作用特性，包括摩擦系數(shù)、接觸剛度等。1.3.1設(shè)置接觸屬性接觸屬性通過CPLSTN或CPLSTN3D卡來定義，具體取決于分析的類型（2D或3D）。1.3.2示例定義接觸屬性，包括摩擦系數(shù)和接觸剛度：$Definecontactproperty

CPLSTN3D,1,1,0.3,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0

#四、模型建立與網(wǎng)格劃分

##4.1幾何模型導(dǎo)入

在進行彈性力學(xué)仿真分析，尤其是使用MSCNastran進行接觸分析時，首先需要導(dǎo)入幾何模型。這一步驟是將設(shè)計階段的CAD模型轉(zhuǎn)換為仿真軟件可以識別和處理的格式。MSCNastran支持多種CAD文件格式的導(dǎo)入，包括但不限于IGES,STEP,Parasolid,ACIS等。

###導(dǎo)入步驟

1.**打開MSCNastran界面**：啟動MSCNastran軟件，進入預(yù)處理環(huán)境。

2.**選擇導(dǎo)入功能**：在菜單欄中選擇“File”>“Import”，或者使用快捷鍵進行操作。

3.**選擇文件類型**：在彈出的對話框中，選擇CAD模型的文件類型，例如STEP或IGES。

4.**瀏覽并選擇文件**：從計算機中選擇需要導(dǎo)入的幾何模型文件。

5.**導(dǎo)入設(shè)置**：在導(dǎo)入前，可以設(shè)置導(dǎo)入選項，如單位系統(tǒng)、坐標(biāo)系等，確保模型與仿真環(huán)境的兼容性。

6.**執(zhí)行導(dǎo)入**：點擊“導(dǎo)入”或“打開”按鈕，開始導(dǎo)入過程。

7.**檢查模型**：導(dǎo)入完成后，檢查模型是否完整，包括幾何形狀、尺寸和坐標(biāo)位置等。

###注意事項

-**單位一致性**：確保導(dǎo)入模型的單位與MSCNastran中設(shè)置的單位一致，避免因單位不匹配導(dǎo)致的仿真結(jié)果錯誤。

-**模型簡化**：在導(dǎo)入前，考慮對模型進行簡化，去除不必要的細節(jié)，以減少計算時間和資源消耗。

-**修復(fù)幾何錯誤**：導(dǎo)入的模型可能包含幾何錯誤，如重疊面、未封閉的實體等，需要在導(dǎo)入后進行修復(fù)。

##4.2網(wǎng)格類型選擇

網(wǎng)格劃分是將連續(xù)的幾何模型離散化為有限數(shù)量的單元，以便進行數(shù)值計算。在MSCNastran中，根據(jù)模型的復(fù)雜性和分析需求，可以選擇不同的網(wǎng)格類型。

###常見網(wǎng)格類型

1.**四面體網(wǎng)格**（TetrahedralMesh）：適用于復(fù)雜幾何，能夠較好地適應(yīng)不規(guī)則形狀，但可能在某些情況下精度較低。

2.**六面體網(wǎng)格**（HexahedralMesh）：提供更高的計算精度，適用于規(guī)則幾何，但在復(fù)雜模型中生成較為困難。

3.**殼單元網(wǎng)格**（ShellElements）：用于薄殼結(jié)構(gòu)的分析，能夠有效模擬殼體的彎曲和剪切行為。

4.**梁單元網(wǎng)格**（BeamElements）：適用于長細比大的結(jié)構(gòu)，如梁和桁架，能夠簡化模型，提高計算效率。

###選擇依據(jù)

-**模型幾何**：根據(jù)模型的幾何復(fù)雜度選擇網(wǎng)格類型，規(guī)則幾何適合六面體網(wǎng)格，復(fù)雜幾何則四面體網(wǎng)格更為適用。

-**分析類型**：不同的分析類型（如靜態(tài)分析、動態(tài)分析、熱分析等）可能對網(wǎng)格類型有特定要求。

-**計算資源**：六面體網(wǎng)格雖然精度高，但生成和計算可能需要更多的計算資源和時間。

###網(wǎng)格劃分步驟

1.**定義網(wǎng)格參數(shù)**：在MSCNastran中，設(shè)置網(wǎng)格尺寸、單元類型等參數(shù)。

2.**執(zhí)行網(wǎng)格劃分**：選擇“Mesh”>“Generate”，開始網(wǎng)格劃分過程。

3.**檢查網(wǎng)格質(zhì)量**：網(wǎng)格劃分完成后，檢查網(wǎng)格是否滿足分析需求，包括單元形狀、尺寸和分布等。

##4.3網(wǎng)格質(zhì)量檢查

網(wǎng)格質(zhì)量直接影響仿真結(jié)果的準(zhǔn)確性和計算效率。在MSCNastran中，提供了多種工具和指標(biāo)來檢查和評估網(wǎng)格質(zhì)量。

###檢查指標(biāo)

-**單元形狀**：檢查單元是否為理想形狀，如四面體單元應(yīng)接近正四面體。

-**單元尺寸**：確保網(wǎng)格尺寸在模型中均勻分布，避免局部過密或過疏。

-**網(wǎng)格平滑度**：檢查網(wǎng)格是否平滑，避免出現(xiàn)尖銳的角或突變的單元尺寸。

-**網(wǎng)格連通性**：確保所有單元正確連接，沒有孤立的單元或重疊的單元。

###檢查工具

-**網(wǎng)格可視化**：使用MSCNastran的圖形界面，可視化網(wǎng)格，直觀檢查網(wǎng)格形狀和分布。

-**網(wǎng)格質(zhì)量報告**：生成網(wǎng)格質(zhì)量報告，詳細列出網(wǎng)格的各項指標(biāo)，便于分析和調(diào)整。

-**網(wǎng)格優(yōu)化工具**：利用內(nèi)置的網(wǎng)格優(yōu)化工具，自動調(diào)整網(wǎng)格，提高網(wǎng)格質(zhì)量。

###優(yōu)化策略

-**局部細化**：在模型的關(guān)鍵區(qū)域或應(yīng)力集中區(qū)域，適當(dāng)增加網(wǎng)格密度，提高計算精度。

-**全局調(diào)整**：根據(jù)網(wǎng)格質(zhì)量報告，全局調(diào)整網(wǎng)格參數(shù)，如單元尺寸，以達到整體最優(yōu)。

-**使用高級網(wǎng)格技術(shù)**：如自適應(yīng)網(wǎng)格劃分，根據(jù)計算過程中的應(yīng)力分布動態(tài)調(diào)整網(wǎng)格，提高效率和精度。

###示例：網(wǎng)格質(zhì)量檢查

假設(shè)我們已經(jīng)完成了一個模型的網(wǎng)格劃分，現(xiàn)在需要檢查網(wǎng)格質(zhì)量。以下是一個使用MSCNastran進行網(wǎng)格質(zhì)量檢查的示例：

```python

#假設(shè)使用Python接口與MSCNastran交互

importpyNastran

#加載網(wǎng)格數(shù)據(jù)

bdf=pyNastran.BDF()

bdf.read_bdf('model.bdf')

#檢查單元形狀

foreleminbdf.elements.values():

ifelem.type=='CTETRA':#檢查四面體單元

shape_quality=elem.check_shape_quality()

print(f"ElementID:{elem.eid},ShapeQuality:{shape_quality}")

#檢查單元尺寸

foreleminbdf.elements.values():

ifelem.type=='CTETRA':#檢查四面體單元

size=elem.get_element_size()

print(f"ElementID:{elem.eid},Size:{size}")

#生成網(wǎng)格質(zhì)量報告

bdf.write_bdf('model_quality.bdf',size=16,is_double=False,encoding='utf-8')在上述示例中，我們首先加載了網(wǎng)格數(shù)據(jù)，然后檢查了每個四面體單元的形狀質(zhì)量和尺寸。最后，生成了一個網(wǎng)格質(zhì)量報告，便于進一步分析和優(yōu)化。通過這些步驟，可以確保模型的網(wǎng)格質(zhì)量滿足仿真分析的要求，為后續(xù)的接觸分析奠定堅實的基礎(chǔ)。2材料屬性與邊界條件2.11材料屬性定義在進行彈性力學(xué)仿真分析，尤其是使用MSCNastran進行接觸分析時，正確定義材料屬性至關(guān)重要。材料屬性包括但不限于彈性模量、泊松比、密度、熱膨脹系數(shù)等，這些屬性直接影響結(jié)構(gòu)的響應(yīng)和接觸行為。2.1.1彈性模量與泊松比彈性模量（Young’sModulus）和泊松比（Poisson’sRatio）是描述材料在彈性變形階段力學(xué)行為的基本參數(shù)。在MSCNastran中，可以通過MAT1卡片來定義這些屬性。2.1.1.1示例代碼MAT1130000.00.32.78E-04MAT1表示材料屬性定義。1是材料ID，用于后續(xù)引用。30000.0是彈性模量，單位為psi。0.3是泊松比。2.78E-04是密度，單位為lb/in^3。2.1.2密度密度是材料單位體積的質(zhì)量，對于動態(tài)分析尤為重要。在MAT1卡片中，密度通常作為第三個參數(shù)輸入。2.1.3熱膨脹系數(shù)熱膨脹系數(shù)（CoefficientofThermalExpansion,CTE）描述材料隨溫度變化而膨脹或收縮的特性。在涉及溫度變化的分析中，CTE是必須定義的參數(shù)之一。2.1.3.1示例代碼MAT1230000.00.32.78E-04

6.0E-066.0E-06是熱膨脹系數(shù)，單位為1/°F。2.22邊界條件設(shè)置邊界條件（BoundaryConditions,BCs）定義了模型的約束，包括固定點、旋轉(zhuǎn)約束、位移約束等。在接觸分析中，邊界條件的設(shè)置直接影響接觸面的相對運動。2.2.1固定點約束固定點約束通常用于模擬結(jié)構(gòu)的支撐或固定端。在MSCNastran中，使用SPC卡片來定義固定點。2.2.1.1示例代碼SPC11,2,31是網(wǎng)格ID，表示網(wǎng)格點1被固定。1,2,3分別表示在X、Y、Z方向上的位移被約束。2.2.2旋轉(zhuǎn)約束旋轉(zhuǎn)約束用于限制結(jié)構(gòu)在特定軸上的旋轉(zhuǎn)。使用RBE3卡片可以定義旋轉(zhuǎn)約束。2.2.2.1示例代碼RBE31001010.00.00.0

1020.00.00.0

1030.00.00.0100是剛體ID。101,102,103是網(wǎng)格點ID，分別用于控制剛體在X、Y、Z軸上的旋轉(zhuǎn)。2.33載荷施加方法載荷（Loads）是驅(qū)動結(jié)構(gòu)響應(yīng)的動力源，包括力、力矩、壓力、溫度等。在接觸分析中，載荷的施加方式影響接觸力的分布和大小。2.3.1力的施加力的施加通常使用FORCE卡片。在接觸分析中，力的施加點和方向需要仔細考慮，以確保模擬的準(zhǔn)確性。2.3.1.1示例代碼FORCE120.0100.00.01是施加力的網(wǎng)格點ID。2是力的方向，這里表示沿Y軸施加力。100.0是力的大小，單位為lbf。2.3.2壓力的施加壓力的施加通常使用PLOAD卡片。在接觸分析中，壓力可以模擬面接觸的載荷。2.3.2.1示例代碼PLOAD12100.00.00.01是施加壓力的網(wǎng)格點ID。2是壓力的方向，這里表示沿Y軸施加壓力。100.0是壓力的大小，單位為psi。2.3.3溫度載荷溫度載荷可以使用TEMP卡片來施加，這對于熱-結(jié)構(gòu)耦合分析尤為重要。2.3.3.1示例代碼TEMP1100.01是網(wǎng)格點ID。100.0是溫度值，單位為°F。通過上述材料屬性定義、邊界條件設(shè)置和載荷施加方法的詳細講解，可以確保在使用MSCNastran進行接觸分析時，模型能夠準(zhǔn)確反映實際工況，從而獲得可靠的仿真結(jié)果。3接觸分析前處理3.11接觸面預(yù)處理在進行MSCNastran的接觸分析前，接觸面的預(yù)處理是至關(guān)重要的步驟。接觸面預(yù)處理主要包括幾何清理、網(wǎng)格劃分、定義接觸屬性等，確保接觸分析的準(zhǔn)確性和穩(wěn)定性。3.1.1幾何清理幾何清理涉及去除模型中的小特征、銳邊、重疊面等，這些小特征可能在實際分析中并不重要，但在接觸分析中可能會導(dǎo)致網(wǎng)格問題或接觸識別錯誤。3.1.1.1示例假設(shè)我們有一個包含銳邊和小特征的模型，需要在Nastran中進行接觸分析。在進行接觸分析前，我們可以通過以下步驟進行幾何清理：去除銳邊：使用CAD軟件中的倒圓角功能，對模型的銳邊進行倒圓處理，以減少接觸分析中的應(yīng)力集中。去除小特征：對于直徑小于接觸分析中最小網(wǎng)格尺寸的小孔或凸起，可以考慮在CAD軟件中直接刪除，以簡化模型。3.1.2網(wǎng)格劃分接觸分析中，網(wǎng)格的質(zhì)量直接影響接觸識別的準(zhǔn)確性。通常，接觸面的網(wǎng)格需要比非接觸面更細，以確保接觸識別的精度。3.1.2.1示例在Nastran中，可以使用以下命令進行網(wǎng)格劃分：GRID,1,101,0.0,0.0

GRID,2,102,1.0,0.0

GRID,3,103,1.0,1.0

GRID,4,104,0.0,1.0

CQUAD4,1001,1,2,3,4這段代碼定義了四個網(wǎng)格點和一個四邊形網(wǎng)格元素。在接觸分析中，接觸面的網(wǎng)格可能需要更密集，例如，通過減小網(wǎng)格點之間的距離來實現(xiàn)。3.1.3定義接觸屬性接觸屬性包括接觸類型（如面-面接觸、點-面接觸）、摩擦系數(shù)、接觸剛度等，這些屬性的定義直接影響接觸分析的結(jié)果。3.1.3.1示例在Nastran中定義接觸屬性，可以使用以下命令：CTABLE,1,1,0.3,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0

CSTIFF,1,1,1000000.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0CTABLE定義了接觸表，其中0.3是摩擦系數(shù)。CSTIFF定義了接觸剛度，1000000.0是法向接觸剛度。3.22初始間隙設(shè)置初始間隙是指在接觸分析開始時，接觸面之間的距離。正確的初始間隙設(shè)置可以避免模型中的穿透問題，確保接觸分析的正確性。3.2.1示例在Nastran中，可以通過以下命令設(shè)置初始間隙：CGAP,1,1,2,0.001這里CGAP定義了接觸間隙，1和2是接觸面的網(wǎng)格ID，0.001是初始間隙的大小。3.33接觸對檢查接觸對檢查是確保接觸分析設(shè)置正確的重要步驟。通過檢查接觸對，可以發(fā)現(xiàn)模型中可能存在的穿透問題、接觸面定義錯誤等問題。3.3.1示例在Nastran中，可以使用以下命令進行接觸對檢查：CLOAD,1,1,0.0,0.0,0.0,0.0,0.0,0.0雖然CLOAD命令通常用于定義載荷，但在接觸對檢查中，可以使用它來施加一個非常小的力，觀察接觸面的響應(yīng)，以檢查接觸設(shè)置是否正確。然而，Nastran本身并沒有直接的命令用于接觸對檢查，通常這一步驟需要在前處理器中完成，如Patran，通過其圖形界面和工具來檢查接觸對的定義是否合理。3.3.1檢查步驟加載模型：在前處理器中加載已完成網(wǎng)格劃分和接觸屬性定義的模型。檢查接觸面：使用前處理器的工具檢查接觸面的定義，確保接觸面的網(wǎng)格質(zhì)量，沒有穿透或重疊。檢查接觸對：確認(rèn)接觸對的定義是否正確，包括接觸面和目標(biāo)面的對應(yīng)關(guān)系，以及接觸屬性的設(shè)置。通過以上步驟，可以確保接觸分析前處理的正確性，為后續(xù)的接觸分析提供堅實的基礎(chǔ)。4求解設(shè)置與后處理4.11求解器選擇在進行彈性力學(xué)仿真分析，尤其是使用MSCNastran進行接觸分析時，選擇合適的求解器至關(guān)重要。MSCNastran提供了多種求解器，包括直接求解器和迭代求解器，每種求解器都有其特定的應(yīng)用場景和優(yōu)勢。4.1.1直接求解器直接求解器，如SOL101和SOL103，適用于中小型問題，能夠提供精確的解，但可能需要較大的內(nèi)存和較長的計算時間。SOL101適用于靜態(tài)線性分析，而SOL103則適用于頻域分析。4.1.2迭代求解器迭代求解器，如SOL106和SOL111，適用于大型問題，尤其是當(dāng)內(nèi)存限制成為瓶頸時。這些求解器通過逐步逼近的方式找到解，可能犧牲一定的精度以換取計算效率。SOL106適用于非線性靜態(tài)分析，而SOL111則適用于非線性動態(tài)分析。4.22求解控制參數(shù)在MSCNastran中，求解控制參數(shù)的設(shè)置直接影響分析的精度和效率。以下是一些關(guān)鍵的控制參數(shù)：NLPCI：控制非線性分析的收斂準(zhǔn)則，較低的值意味著更嚴(yán)格的收斂要求，但可能增加計算時間。NLPCG：控制非線性分析的迭代次數(shù)，較高的值允許更多的迭代，以達到收斂。NLPCD：控制接觸檢測的精度，較高的值意味著更精確的接觸檢測，但可能增加計算復(fù)雜度。4.2.1示例：設(shè)置求解控制參數(shù)SUBCASE1

ANALYSIS=NLSTAT

SOL=106

NLPCI=1E-6

NLPCG=50

NLPCD=1E-3

LOAD=1

DISPLACEMENT=ALL

STRESS=ALL

STRAIN=ALL

CONTACT=ALL

END在上述示例中，我們選擇了SOL106作為求解器，進行非線性靜態(tài)分析。NLPCI設(shè)置為1E-6，意味著收斂準(zhǔn)則非常嚴(yán)格。NLPCG設(shè)置為50，允許求解器進行最多50次迭代以達到收斂。NLPCD設(shè)置為1E-3，提供了一個相對較高的接觸檢測精度。4.33結(jié)果可視化與分析完成求解后，結(jié)果的可視化和分析是理解仿真結(jié)果的關(guān)鍵步驟。MSCNastran通常與后處理軟件如Patran或HyperView配合使用，以提供直觀的結(jié)果展示。4.3.1Patran中的結(jié)果可視化在Patran中，可以使用以下步驟來可視化MSCNastran的分析結(jié)果：加載結(jié)果文件：首先，需要加載由MSCNastran生成的結(jié)果文件，通常是.f06或.op2格式。選擇結(jié)果類型：然后，從結(jié)果類型列表中選擇要查看的結(jié)果，如位移、應(yīng)力、應(yīng)變或接觸壓力。調(diào)整顯示設(shè)置：可以調(diào)整顏色映射、等值線、矢量顯示等設(shè)置，以更清晰地展示結(jié)果。創(chuàng)建動畫：對于動態(tài)分析，可以創(chuàng)建動畫來觀察模型在時間或頻率域內(nèi)的行為。4.3.2示例：在Patran中查看位移結(jié)果加載結(jié)果：在Patran中，通過菜單File>Load>NastranResults加載.f06或.op2文件。選擇位移結(jié)果：在結(jié)果樹中，展開Results，選擇Displacement。調(diào)整顯示：在Display面板中，調(diào)整ColorMap和ContourLevels以優(yōu)化結(jié)果的可視化。創(chuàng)建動畫：對于動態(tài)分析，使用Animation面板創(chuàng)建動畫，選擇Time或Frequency作為動畫的驅(qū)動。4.3.3結(jié)果分析結(jié)果分析不僅包括可視化，還應(yīng)包括對結(jié)果的定量評估，如最大應(yīng)力、位移或接觸壓力的計算。這些數(shù)據(jù)可以幫助工程師評估設(shè)計的性能和安全性。4.3.4示例：計算最大應(yīng)力在Patran中，可以使用Tools>Analysis>MaximumStress功能來計算模型中的最大應(yīng)力值。這一步驟通常在設(shè)計驗證階段進行，以確保模型在所有工況下都不會超過材料的強度極限。通過以上步驟，可以有效地設(shè)置MSCNastran的求解參數(shù)，并在Patran中進行結(jié)果的可視化和分析，從而深入理解模型的力學(xué)行為。5接觸分析案例研究5.11案例選擇與背景在工業(yè)設(shè)計與制造中，接觸分析是評估產(chǎn)品性能和預(yù)測潛在故障的關(guān)鍵步驟。本案例研究聚焦于汽車行業(yè)的應(yīng)用，具體是一個汽車門與車框之間的接觸分析。汽車門在關(guān)閉時與車框的接觸，不僅影響車輛的密封性和隔音效果，還直接關(guān)系到乘客的安全。因此，準(zhǔn)確模擬和分析這一接觸過程，對于優(yōu)化設(shè)計和提高車輛質(zhì)量至關(guān)重要。5.1.1背景信息產(chǎn)品設(shè)計：汽車門與車框的設(shè)計需確保在各種條件下（如高速行駛、碰撞等）的緊密接觸。工程挑戰(zhàn)：接觸面的非線性行為、材料屬性、幾何復(fù)雜性等，使得接觸分析成為一項技術(shù)挑戰(zhàn)。分析目標(biāo)：評估接觸壓力分布、接觸剛度、以及接觸對整體結(jié)構(gòu)動態(tài)響應(yīng)的影響。5.22模型建立與分析流程5.2.1模型建立幾何模型：使用CAD軟件（如CATIA或SolidWorks）創(chuàng)建汽車門和車框的精確幾何模型。網(wǎng)格劃分：在MSCNastran中，對模型進行網(wǎng)格劃分，確保接觸區(qū)域的網(wǎng)格密度足夠高，以準(zhǔn)確捕捉接觸行為。材料屬性：定義門和車框的材料屬性，包括彈性模量、泊松比等。邊界條件：設(shè)置門的鉸鏈位置為固定邊界，模擬門的關(guān)閉過程。5.2.2分析流程接觸定義：使用MSCNastran的接觸單元（如CQUAD4或CTRIA3）定義接觸對，指定接觸面和目標(biāo)面。CONTACT=1

CQUAD4,10001,1,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0

1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0上述代碼示例中，CQUAD4定義了一個四邊形接觸單元，10001是單元ID，1是材料屬性ID，后續(xù)數(shù)字代表單元的節(jié)點ID列表。載荷施加：模擬門關(guān)閉時的力，通常在門的把手位置施加一個向內(nèi)的力。求解設(shè)置：選擇適當(dāng)?shù)那蠼馄鳎ㄈ鏢OL101或SOL106），并設(shè)置求解參數(shù)，如求解精度、迭代次數(shù)等。運行分析：提交模型進行求解，生成接觸分析結(jié)果。5.33結(jié)果解釋與工程應(yīng)用5.3.1結(jié)果解釋接觸壓力分布：分析接觸面上的壓力分布，確保壓力均勻，避免局部過壓導(dǎo)致的材料損傷。接觸剛度：評估接觸區(qū)域的剛度，以優(yōu)化設(shè)計，提高車輛的結(jié)構(gòu)穩(wěn)定性和乘客舒適度。動態(tài)響應(yīng)：分析接觸對整體結(jié)構(gòu)動態(tài)響應(yīng)的影響，如振動和噪聲。5.3.2工程應(yīng)用設(shè)計優(yōu)化：基于接觸分析結(jié)果，調(diào)整門和車框的幾何形狀或材料屬性，以改善接觸性能。故障預(yù)測：識別潛在的接觸問題，如過度磨損或材料疲勞，提前進行設(shè)計修改或材料替換。性能驗證：在產(chǎn)品開發(fā)階段，通過接觸分析驗證設(shè)計是否滿足密封性、隔音性和安全性要求。通過本案例研究，我們不僅能夠深入了解MSCNastran在接觸分析中的應(yīng)用，還能掌握如何利用仿真結(jié)果進行有效的工程決策，從而提升產(chǎn)品的設(shè)計質(zhì)量和市場競爭力。6常見問題與解決方案6.11接觸分析失敗原因在使用MSCNastran進行接觸分析時，失敗可能由多種因素引起。以下是一些常見的失敗原因及其排查方法：網(wǎng)格質(zhì)量不佳：接觸面的網(wǎng)格如果過于粗糙或存在扭曲，可能導(dǎo)致接觸識別失敗。確保接觸區(qū)域的網(wǎng)格密度足夠，且網(wǎng)格質(zhì)量良好。接觸對定義錯誤：正確定義接觸對是接觸分析的關(guān)鍵。檢查是否正確指定了主從面，以及接觸屬性是否設(shè)置得當(dāng)。初始間隙設(shè)置不當(dāng)：過大的初始間隙可能導(dǎo)致接觸識別算法無法收斂。調(diào)整初始間隙，確保其合理且接近實際物理狀態(tài)。約束條件不足：接觸分析中，模型的約束條件必須足夠以防止剛體運動。檢查模型的約束，確保所有自由度都被合理限制。材料屬性不準(zhǔn)確：材料的彈性模量、泊松比等屬性對接觸分析結(jié)果有直接影響。確認(rèn)材料屬性是否準(zhǔn)確無誤。求解器設(shè)置不當(dāng)：選擇合適的求解器和求解參數(shù)對接觸分析至關(guān)重要。檢查求解器設(shè)置，確保其適合當(dāng)前的分析類型。6.22收斂性問題處理收斂性問題是接觸分析中常見的挑戰(zhàn)，處理這些問題通常需要調(diào)整模型設(shè)置或求解參數(shù)。以下是一些處理收斂性問題的策略：細化網(wǎng)格：在接觸區(qū)域增加網(wǎng)格密度，可以提高接觸識別的準(zhǔn)確性，從而改善收斂性。調(diào)整接觸參數(shù)：例如，增加接觸迭代次數(shù)，或調(diào)整接觸算法的收斂準(zhǔn)則，如PENALTY或AUGMENTEDLAGRANGE方法。使用預(yù)加載：在分析開始時施加一個小的預(yù)加載，可以幫助接觸面更好地識別和接觸，從而改善收斂性。檢查初始條件：確保模型的初始條件合理，如初始間隙、初始速度和加速度等。增加時間步長控制：在瞬態(tài)分析中，適當(dāng)?shù)臅r間步長控制可以提高求解效率和收斂性。使用子步：在關(guān)鍵的接觸階段使用更小的子步，可以更精確地捕捉接觸行為，有助于收斂。6.33結(jié)果不準(zhǔn)確的排查方法當(dāng)接觸分析的結(jié)果與預(yù)期不符時，以下步驟可以幫助排查和解決結(jié)果不準(zhǔn)確的問題：驗證模型設(shè)置：重新檢查模型的幾何、材料屬性、邊界條件和載荷，確保它們與實際物理情況一致。檢查接觸對定義：確認(rèn)接觸對的定義是否正確，包括主從面的選擇、接觸屬性和摩擦系數(shù)等。分析網(wǎng)格影響：進行網(wǎng)格敏感性分析，檢查不同網(wǎng)格密度下的結(jié)果差異，以確定網(wǎng)格是否是影響結(jié)果準(zhǔn)確性的因素。求解器設(shè)置審查：檢查求解器的設(shè)置，包括求解方法、收斂準(zhǔn)則和求解參數(shù)，確保它們適合當(dāng)前的分析需求。結(jié)果后處理：使用后處理工具仔細檢查結(jié)果