{"id":454217,"date":"2026-03-11T20:49:20","date_gmt":"2026-03-11T20:49:20","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/explicit-thermal-solver-crash-with-s-ale-mesh-setid-amp-phase-change\/"},"modified":"2026-03-11T20:49:20","modified_gmt":"2026-03-11T20:49:20","slug":"explicit-thermal-solver-crash-with-s-ale-mesh-setid-amp-phase-change","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/explicit-thermal-solver-crash-with-s-ale-mesh-setid-amp-phase-change\/","title":{"rendered":"Explicit Thermal Solver Crash with S-ALE Mesh \u2013 SETID & Phase Change"},"content":{"rendered":"

<div class=”text-neutral-content”><div class=”mb-sm mb-xs px-md xs:px-0 overflow-hidden” data-post-click-location=”text-body”><div id=”t3_1rr5r9z-post-rtjson-content” class=”md text-14-scalable pb-2xs [–emote-size:20px]” dir=”auto”><p>Hi,<\/p><p>I’m modeling hypervelocity impact (2.22 km\/s tungsten carbide sphere on HSLA-100 steel) with coupled thermal-structural analysis using S-ALE (Structured ALE) mesh.<\/p><p>Initial Attempt & Issue:<\/p><p>I first tried the implicit thermal solver using:<\/p><p>- *CONTROL_SOLUTION (Thermal-Structural Analysis)<\/p><p>- *CONTROL_THERMAL_NONLINEAR<\/p><p>- *CONTROL_THERMAL_SOLVER<\/p><p>- *CONTROL_THERMAL_TIMESTEP<\/p><p>However, I observed physically unrealistic temperature rates (dT\/dt on the order of billions of °K), which is physically impossible. I switched to the Explicit Thermal Solver (*CONTROL_EXPLICIT_THERMAL_* cards) as an alternative, but encountered a fatal initialization error.<\/p><p>Current Error:<\/p><p><\/code><\/p><p>forrtl: severe (164): Program Exception - integer divide by zero<\/p><p>Image PC Routine Line Source<\/p><p>lsdyna_mpp_dp_imp 00007FF731E6B4CC XPLCTH_INIT 1148 dyn20x.F<\/p><p>...<\/p><p><\/code><\/code><\/p><p>The crash occurs during initialization (XPLCTH_INIT<\/code>), suggesting a division by zero in the thermal data setup.<\/p><p>Specific Questions:<\/p><\/p>\n

    \n
  1. <p>Explicit Thermal Setup with S-ALE:<\/p><p>For cards like *DATABASE_ALE<\/code>, *CONTROL_EXPLICIT_THERMAL_INITIAL<\/code>, and *CONTROL_EXPLICIT_THERMAL_OUTPUT<\/code>, the manual states SETID can be left blank for “all parts,” but LS-PrePost\/LS-DYNA requires an integer. Since S-ALE mesh elements are generated internally at runtime (not predefined in *ELEMENT_SHELL<\/code>), I cannot reference them via traditional *SET_SHELL_LIST<\/code>.<\/p><p>- How do I properly define SETID for S-ALE domains in these cards? Should I use *SET_MULTI_MATERIAL_GROUP<\/code> instead?<\/p><\/li>\n
  2. <p>Phase Change Modeling:<\/p><p>My material definition includes *MAT_THERMAL_ISOTROPIC_PHASE_CHANGE<\/code> for the steel target (solid-to-liquid). Does the Explicit Thermal Solver support phase change energy (latent heat), or is this capability restricted to the implicit thermal solver? If supported, are there specific considerations for S-ALE multi-material groups?<\/p><\/li>\n
  3. <p>Divide-by-Zero Cause:<\/p><p>The error trace points to XPLCTH_INIT<\/code> (dyn20x.F:1148). This typically indicates zero thermal mass (density × specific heat) in a thermal part definition. Given that my vacuum\/void material (*MAT_ALE_VACUUM<\/code>) has near-zero thermal properties, could this be triggering the crash? Should vacuum regions be excluded from the thermal solver via *SET_PART_LIST<\/code>, or is there a minimum non-zero thermal density requirement?<\/p><\/li>\n<\/ol>\n

    <p>Model Context:<\/p><p>- 2D Axisymmetric S-ALE mesh (fine resolution)<\/p><p>- 3 ALE Multi-Material Groups: HSLA-100 Steel, Tungsten Carbide, Vacuum<\/p><p>- Thermal properties defined via *MAT_THERMAL_ISOTROPIC and *MAT_THERMAL_ISOTROPIC_PHASE_CHANGE<\/p><p>- Using MPP R14.1.1 on Windows<\/p><p>Keyword file attached for reference:<\/p><p><a class=”relative pointer-events-auto a cursor-pointer<\/p>\n

    underline” href=”https:\/\/buffalo.box.com\/s\/y7rz3bqg4xsvuir6z94b50mcg2g3jp1s” target=”_blank” rel=”noopener”>https:\/\/buffalo.box.com\/s\/y7rz3bqg4xsvuir6z94b50mcg2g3jp1s<\/a><\/p><p>Any guidance on proper explicit thermal initialization with S-ALE and phase change setup would be greatly appreciated.<\/p><p>Thanks,<\/p><p>Amrith<\/p><\/div><\/div><\/div><div> <\/div><\/p>\n","protected":false},"template":"","class_list":["post-454217","topic","type-topic","status-publish","hentry","topic-tag-explicit","topic-tag-thermal-gradient","topic-tag-thermal-model"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["454217"],"_bbp_subscription":["270765","58821","21501"],"_bbp_author_ip":["128.205.116.177"],"_bbp_last_reply_id":["454327"],"_bbp_last_active_id":["454327"],"_bbp_last_active_time":["2026-03-12 20:48:18"],"_bbp_reply_count":["4"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["3"],"_bbp_engagement":["270765","58821","21501"],"_btv_view_count":["115"],"_bbp_topic_status":["unanswered"],"_bbp_notification_enabled":["270765"]},"test":"amrithmabuffalo-edu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/454217","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/454217\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=454217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}