{"id":394170,"date":"2024-11-19T06:12:01","date_gmt":"2024-11-19T06:12:01","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/problem-with-restart-ls-dyna-amp-polyumod\/"},"modified":"2024-11-19T06:12:01","modified_gmt":"2024-11-19T06:12:01","slug":"problem-with-restart-ls-dyna-amp-polyumod","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/problem-with-restart-ls-dyna-amp-polyumod\/","title":{"rendered":"Problem with restart LS-DYNA &amp; PolyUMod"},"content":{"rendered":"<p>&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;Hello,&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;I am solving the problem of deformation of an energy-absorbing device for a railway car in two stages:&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;1st stage &#8211; static compression and a long period of relaxation&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;2nd stage &#8211; cargo drop&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;for the first stage, you need to use an implicit solver&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;for the second stage, you need to use an explicit solver&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;I tried to use the LS-DYNA program (Revision: R13.0-365-gf8a97bda2a) and the external library of materials PolyUMod.&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;This problem was solved only by using an implicit solver for the entire problem.&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;But this method turned out to be unprofitable due to the long solution time.&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;I tried to use a &#8220;full restart&#8221;, but it turned out that when the model uses the external library of materials PolyUMod, LS-DYNA cannot use the results obtained at the first step for the second step (restart).&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;LS-DYNA reads the solution results from the first step, but then they are &#8220;zeroed out&#8221;.&lt;br class=&#8221;html-br&#8221;&gt;&lt;br class=&#8221;html-br&#8221;&gt;*** I use&nbsp;&lt;span class=&#8221;html-span xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1hl2dhg x16tdsg8 x1vvkbs&#8221;&gt;&lt;strong class=&#8221;html-strong xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1hl2dhg x16tdsg8 x1vvkbs x1s688f&#8221;&gt;EFG<\/strong>&lt;\/span&gt;&nbsp;formulation&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;Maybe someone could find a way to solve similar problems?&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;*** I also tried to solve this problem using the material model 318, implemented in the LS-DYNA program (Revision: R14.1.1-4-gaf1eb871e8 | AnLicVer: 2024 R2 (20240501+dl-65-gb272478), but unfortunately I could not solve even the first stage of this problem.&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;It is very likely that the implemented material model 318 has some &#8220;disadvantages&#8221;&#8230;&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&nbsp;&lt;\/div&gt;&lt;\/div&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm xat24cr x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd&#8221; tabindex=&#8221;-1&#8243;&gt;&lt;div class=&#8221;html-div xdj266r x11i5rnm x1mh8g0r xexx8yu x4uap5 x18d9i69 xkhd6sd x1e56ztr&#8221;&gt;&lt;span class=&#8221;x193iq5w xeuugli x13faqbe x1vvkbs x1xmvt09 x6prxxf xvq8zen xo1l8bm xzsf02u&#8221;&gt;Regards Valery&lt;br&gt;<img decoding=\"async\" src=\"https:\/\/scontent-ams4-1.xx.fbcdn.net\/v\/t39.30808-6\/467308602_27486528750962050_1309721633917656516_n.jpg?stp=dst-jpg_p526x296&amp;_nc_cat=102&amp;ccb=1-7&amp;_nc_sid=aa7b47&amp;_nc_ohc=_BQ1FtDhGGwQ7kNvgEc2ziw&amp;_nc_zt=23&amp;_nc_ht=scontent-ams4-1.xx&amp;_nc_gid=A7sToaR37HkhWQqKU8MMGXL&amp;oh=00_AYBpL8nsAKCBjHodDdE9qgNlH71U1YU943EROV9wOH1oJA&amp;oe=67417ECA\" alt=\"\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u043e, \u044d\u0442\u043e \u0433\u0440\u0430\u0444\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u043e\u0431\u0440\u0430\u0437 (\u0442\u0435\u043a\u0441\u0442 &laquo;Y-displacement 7.141e-03 -3.980e+00_ -7.967e+00 -1.195e+01 -1.594e+01 -1.993e+01 -2.392e+01_ -2.790e+01 -2.7 -3.189e+01 -3. -3.588e+01 -3.986+01 -4.385e+01 -4.784e+01_ -5.183e+01 -5.581e+01 -5.980e+01 -6.379e+01 -6.777e+01_ -7.176e+01 -7.575e+01 -7.974e+01 -8.372e+01 -8.771e+01 -9.170e+01 -9.568e+01 -9.967e+01_ -1.037e+02_ -1.076e+02_ -1.116e+02_ -1.156e+02_ -1.196e+02_&raquo;)\" \/>&lt;\/span&gt;&lt;\/div&gt;&lt;\/div&gt;<\/p>\n","protected":false},"template":"","class_list":["post-394170","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["469525","480261"],"_bbp_author_ip":["46.161.0.18"],"_btv_view_count":["229"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["394170"],"_bbp_forum_id":["27814"],"_bbp_engagement":["469525","480261"],"_bbp_voice_count":["2"],"_bbp_reply_count":["10"],"_bbp_last_reply_id":["395067"],"_bbp_last_active_id":["395067"],"_bbp_last_active_time":["2024-11-23 20:53:00"]},"test":"valerym-m5gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/394170","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\/394170\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=394170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}