# Altair HyperXtrude 2022.1 Release Notes

Altair HyperXtrude is a suite of finite element solvers for simulating the following manufacturing processes.
• Binder Jet Sintering
• Metal Extrusion
• Polymer Extrusion
• Quenching
• Calibration
• Metal Rolling
• Friction Stir Welding
• Resin Transfer Molding

## Highlights

Highlights of this release include:
• Arrhenius-type grain growth models are added to the sintering solver
• The sintering solver now predicts cracking during the debinding stage

## Binder Jet Sintering

### New Features

Grain size - Arrhenius Type1 grain growth models
A new grain size model belonging to the class of Arrhenius type functions is implemented. This is a function of:(1) $\frac{dG}{dt}\text{\hspace{0.17em}}=\text{\hspace{0.17em}}\frac{A}{G}\text{ }\mathrm{exp}\text{ }\left(-\frac{Q}{RT}\right)$ Where,
$G$
Grain size
$A$
Pre-exponential factor (Coefficient_A)
$Q$
Activation energy
$R$
Universal gas constant
$T$
Temperature
The solver supports two versions of the above model. The first version (ArrheniusType1 model) requires $A$ and $Q$ as the input and computes the grain growth for a given oven temperature curve. (HXT-526)
Another variation of the grain growth model (ArrheniusType1-Modified) requires $Q$ and grain growth factor (the ratio of the final grain size and the initial grain size) as the inputs. The solvers compute $A$ to ensure that the grain size grows by a factor specified in the grain growth factor during the sintering simulation. (HXT-528)
Crack prediction during the debinding stage
A new feature is implemented in the sintering solver to predict cracking during the debinding stage considering both inter-laminar and intra-laminar shear and tensile stresses. The limits used for predicting this are a function of both the material, the debinding agent, and process conditions. The solver allows component level specification of these limiting stresses used in the Hashin crack criteria. (HXT-525)

### Enhancements

Self-contact is turned off for models with high aspect ratio
Self-contact determination is automatically turned off for models containing elements with a high aspect ratio (greater than 100.0). (HXT-532)
Improvements to Contact Stop Criteria
The solver is improved to avoid false positives in determining self-contact and prematurely stopping the solution. (HXT-527)
STL file of the Compensated Part
The final compensated green part is automatically renamed as CompensatedGreenPart.STL to help identify it easily from the STL files written every compensated iteration. (HXT-520)

## Metal Extrusion

### Enhancements

Improvements to bearing optimization results
The solver is improved to add more details and a summary of bearing optimization runs and results. As a part of this enhancement, a new CSV summarizing the results is created. The OUT file now includes additional details about the bearing optimization run and iterations. (HXT-175)

### Resolved Issues

Bearing Optimization runs all 20 iterations
This is not an issue as the solver looks for a strong convergence and expects every bearing control point to be within the specified tolerance. However, to improve computational efficiency, now the solver uses RMS-based criteria for determining convergence. If the old behavior of a stronger check is needed, you can turned it on by setting the parameter BOStrongConvergenceCheck to yes. The default value of this parameter is no. (HXT-245)
Variable time steps sometimes lead to a solver crash
The solver computes the time step using the variable time step command specified in the input file. Due to an error in implementation which was triggered by rounding off issues, especially the zonal transitions, the time steps were estimated incorrectly at these transitions. This was leading to excessive consumption of the billet during the cycle and hence, a solver crash. The resolution of this issue is applicable only for a single billet cycle or multiple billet cycles with the same billet length in every cycle. (HXT-490)
Solver crashes with error AVERAMPRESS when the press is selected
The solver no longer throws errors while computing average ram pressure for Metal extrusion problems. (HXT-511)
Error in the CSV files
Minor errors from missing commas in the CSV file, which were making files unusable, are now corrected. (HXT-473, HXT-479, HXT-487)

## Quenching

### Resolved Issues

Immersion quenching results diverge from experimental results
The implementation for the heat transfer coefficient computation was enhanced for the immersion quench. Now the solver uses various correlations to model the different regimes of the boiling curve, which includes the nucleate boiling and the membrane (film) boiling. (HXT-523)
Air fan quenching not working in version 2022
The solver now uses the computed values of heat transfer coefficients, so temperature change due to air fan quenching is correctly calculated. (HXT-516)
Center walls cool faster than the outer walls exposed to air fans
All the surfaces in an air fan quench zone were getting quenched even if the surfaces were not directly exposed to the air fans. The solver is now enhanced to consider visibility calculations for computing the cooling effect of an air fan. This helps to treat the surfaces in the quench zone which are exposed to air fans differently from those which are not directly exposed to air fans. Also, now the solver ignores the fan cooling at the points which are outside the impingement width of the fan. (HXT-517)