PCONTHT

Bulk Data Entry

PCONTHT – Define Contact Conductance in Heat Transfer Analysis

Description

Defines conductance for CONTACT elements in heat transfer analysis.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
PCONTHT	PID	KCHTC	KOHTC	TPID	TCID

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
PCONTHT	2	200.0

Contact with automatic determination of KCHTC:

PCONTHT

AUTO

Minimum data required to request pressure based contact HTC:

PCONTHT

Clearance and pressure based contact HTC (see comments 3 and 4):

PCONTHT

150.0

Field	Contents
PID	Property identification number. Must match with a PID of a PCONT bulk data entry. See comment 1. No default (Integer > 0)
KCHTC	Contact Heat Transfer Coefficient (HTC) for the closed contact. See comment 2. No default (Real ≥ 0.0 or AUTO)
KOHTC	Contact Heat Transfer Coefficient (HTC) for the open contact. See comment 2. Default = 10-14 * KCHTC (Real > 0.0). This default is also set when KOHTC =0.
TPID	Identification number of a TABLED# entry. This table specifies conductance per unit contact area (Contact HTC) based on contact pressure. See comments 3 and 4. Default = 0 (Integer > 0)
TCID	Identification number of a TABLED# entry. This table specifies conductance per unit contact area (Contact HTC) based on contact clearance. See comments 3 through 5. Default = 0 (Integer > 0)

Comments

1.	PCONTHT provides Conductance per unit area for CONTACT elements. The PID of a PCONTHT bulk data entry should match the PID of an existing PCONT bulk data entry.

Conductance per unit area is in the same unit as heat transfer coefficients, which is also called contact HTC. Total conductance is calculated by the product of contact HTC and contact area.

KCHTC and KOHTC represent Contact HTC values for closed and open contacts. Theoretically, while higher Contact HTC values enforce a perfect conductor, excessively high values may cause poor conditioning of the conductance matrix. If such conditions are observed, it may be beneficial to reduce the value of Contact HTC, or use clearance and pressure based Contact HTC via TCID and TPID.

To facilitate reasonable values for KCHTC, automatic calculation is supported, specifically:

•	Option KCHTC=AUTO determines the value of KCHTC for each contact element using the contact HTC values of surrounding elements.

TPID points to a TABLED# entry that specifies conductance per unit contact area (Contact HTC) based on contact pressure. Total conductance is the product of table value and actual contact area. TPID is used when Thermal Contact Analysis uses STATSUB(STRUCTURE) to reference the Contact status from a static subcase. TPID overrides KCHTC for coupled thermal contact analysis.

TCID points to a TABLED# entry that specifies conductance per unit contact area based on contact clearance. TCID overrides KOHTC for coupled thermal contact analysis, where nonlinear static subcase provides contact status for thermal contact. TPID can be specified together with TCID. When TPID is specified together with TCID, contact HTC is determined from the table with TCID for open contact (overrides KOHTC), and from the table with TPID for closed contact. TCID overrides KCHTC for closed contact if TPID is not present.

5.	For clearance-based Contact HTC table look-up, Contact HTC is linearly interpolated within the table range (which should start from zero clearance), and it becomes zero when extrapolated outside the table range.

6.	PCONTHT is not supported for surface-to-surface contact (DISCRET=S2S on CONTACT/TIE).

7.	For CONTACT interfaces without PCONT, PCONTHT is not required. Thermal Contact HTC values based on KCHTC=AUTO will be utilized in such cases.

8.	Thermal-structural analysis problems involving contact are fully coupled since contact/gap status changes thermal conductivity. Refer to Contact-based Thermal Analysis in the User’s Guide for more information.

9.	This card is represented as a property in HyperMesh.