{"id":13446,"date":"2020-04-30T05:47:10","date_gmt":"2020-04-30T09:47:10","guid":{"rendered":"https:\/\/blogs.sw.siemens.com\/simcenter\/?p=13446"},"modified":"2026-03-26T06:09:51","modified_gmt":"2026-03-26T10:09:51","slug":"simrod-experience-mode-shapes-in-modal-analysis-need-test-calibration","status":"publish","type":"post","link":"https:\/\/blogs.sw.siemens.com\/simcenter\/simrod-experience-mode-shapes-in-modal-analysis-need-test-calibration\/","title":{"rendered":"SimRod experience: Mode shapes in modal analysis need test-calibration"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3-1024x683.jpg\" alt=\"SimRod\" class=\"wp-image-13450\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3-1024x683.jpg 1024w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3-600x400.jpg 600w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3-768x512.jpg 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3-1536x1024.jpg 1536w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3-1110x740.jpg 1110w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3.jpg 1600w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption>SimRod: Pure driving fun! Very true, but how far does it take you?<\/figcaption><\/figure>\n\n\n\n<p>Ever heard of \u201c<em>Range anxiety<\/em>\u201d?&nbsp;The Wikipedia definition of this new term is <em>\u201c<a href=\"https:\/\/en.wikipedia.org\/wiki\/Fear\" target=\"_blank\" rel=\"noopener\">fear<\/a>&nbsp;that a vehicle has insufficient range to reach its destination and would thus strand the vehicle&#8217;s occupants.\u201d<\/em> The battle is on: car manufacturers all over the world are looking for ways to increase the range of their vehicles. Obviously, a lot of effort is spent on optimizing the drivetrain. But this is just one of the many battlefronts. Learn more how mode shapes in modal analysis can be your collaborative partners.  &nbsp;   <\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Put your car body on a diet!<\/strong><\/h2>\n\n\n\n<p>Another important factor is total vehicle weight, aka <a href=\"https:\/\/en.wikipedia.org\/wiki\/Curb_weight\" target=\"_blank\" rel=\"noopener\">curb weight<\/a>. Consequently, lightweight body design is high on the priority list. But weight also plays a crucial role in other performance characteristics of the vehicle. A lighter design may cause unacceptable NVH or driving dynamics performance. It\u2019s all a matter of finding the right balance. The <a rel=\"noreferrer noopener\" aria-label=\"Simcenter solutions (opens in a new tab)\" href=\"https:\/\/www.plm.automation.siemens.com\/global\/en\/products\/simcenter\/\" target=\"_blank\">Simcenter solutions<\/a> help you to find that balance, combining performance prediction and testing tools in one and the same platform. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Don\u2019t accept extra range in exchange for driving fun. Go for both!<\/strong><\/h2>\n\n\n\n<p>The key  capability in the Simcenter performance prediction is to create a reliable structural dynamics model of a vehicle body. To make sure that this model represent reality, Simcenter provides you  with an end-to-end process. This includes running <a href=\"https:\/\/www.plm.automation.siemens.com\/global\/en\/products\/simulation-test\/structural-dynamics-testing.html\" target=\"_blank\" rel=\"noopener\">structural dynamic tests,<\/a> aka modal test, to derive test-based mode shapes in modal analysis, and an extensive set of methods that can be used to correlate and update the Finite Element structural dynamics model.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD-1024x576.jpg\" alt=\"Understanding the impact of weight reduction on performance attributes using modal analysis\" class=\"wp-image-13454\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD-1024x576.jpg 1024w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD-600x338.jpg 600w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD-768x432.jpg 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD-1536x864.jpg 1536w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD-1110x624.jpg 1110w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/SimRod-CAD.jpg 1920w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption> Understanding the impact of weight reduction on performance attributes   <\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"SimRod Series | Structural Dynamics Engineering | Simcenter\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/17vDSrQy614?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What does this look like in reality?<\/strong><\/h2>\n\n\n\n<p>Let\u2019s look at a practical example: the <a href=\"https:\/\/blogs.sw.siemens.com\/simcenter\/good-digital-twins-dont-lie\/\">SimRod<\/a>, a full&nbsp;electric sports car.&nbsp; It is made by <a href=\"https:\/\/kyburz-switzerland.ch\/en\/erod\" target=\"_blank\" rel=\"noopener\">KYBURZ<\/a>, an electric vehicle manufacturer in Switzerland. KYBURZ\u2019s core business is making small electric vehicles with minimal ecological footprint. To showcase our Simcenter solutions, we bought a couple of these electric sports cars.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>The SimRod \u201cBody\u201d<\/strong><\/h2>\n\n\n\n<p>Our SimRod vehicle is a bit special: the body is a frame structure. It consists of a set of welded beams. The beams are made of S235JR steel, a European standard hot rolled non-alloy structural steel grade. It features good plasticity, toughness and weldability. The material density is 7.85 g\/cm3, bringing the total frame weight to 96 kg, which is about 16 % of the total weight of the vehicle. Definitely a large fraction to consider saving a couple of kilos. And by doing so, adding a couple more kilometers of driving fun!<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers-1024x576.png\" alt=\"SimRod frame suspended for testing to obtain data for modal analysis\" class=\"wp-image-13455\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers-1024x576.png 1024w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers-600x338.png 600w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers-768x432.png 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers-1536x864.png 1536w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers-1110x624.png 1110w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/modal-test-traditional-shakers.png 1600w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption>SimRod frame suspended for testing to obtain data for modal analysis      <\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Test vs. Simulation<\/strong><\/h2>\n\n\n\n<p>An anonymous researcher once stated: <em>\u201cNobody believes the result of a   simulation, except the person who performed it, and everybody believes the   result of a test, except the one who ran the test.\u201d<\/em>&nbsp; This old proverb used to be very true, back in the days, when simulation and test were two totally different worlds. The Simcenter platform is designed to remove the boundary between these two worlds and aims to create a test-calibrated simulation model that EVERYBODY believes, simply because it is correct. <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/5-1024x576.png\" alt=\"SimRod frame test setup to define mode shapes in modal analysis\" class=\"wp-image-13456\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/5-1024x576.png 1024w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/5-600x338.png 600w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/5-768x432.png 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/5-1110x624.png 1110w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/5.png 1280w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption> SimRod frame test setup to define mode shapes in modal analysis<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>On your mark, get set, go!<\/strong><\/h2>\n\n\n\n<p>Prior to the testing, CAE engineers usually do some <a rel=\"noreferrer noopener\" aria-label=\"NX Nastran (opens in a new tab)\" href=\"https:\/\/www.plm.automation.siemens.com\/global\/en\/products\/simcenter\/simcenter-nastran.html\" target=\"_blank\">NX Nastran<\/a> runs to estimate the mode shapes. Although these models have limited fidelity, they are useful in early development phases, as they can help making design decisions. This process is much faster and more cost-effective than iterations that involve building prototypes. To close the loop and make everyone believe the prediction, test-calibration is required. <a rel=\"noreferrer noopener\" aria-label=\"Simcenter 3D (opens in a new tab)\" href=\"https:\/\/www.plm.automation.siemens.com\/global\/en\/products\/simcenter\/simcenter-3d.html\" target=\"_blank\">Simcenter 3D<\/a> Structural dynamics uses the preliminary Finite Element model to define the optimal set-up. The analysis helps to define the test wireframe geometry, shaker locations and interface conditions. It also provides a preview of the expected mode shapes in modal analysis. A good preparation is key to successful and efficient test campaign!<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video controls src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Pre-test-1.mp4\"><\/video><figcaption> Using the preliminary, \u2018non-calibrated\u2019 FE prediction to define optimal test setup <\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Simcenter Experimental Modal Analysis \u2013 industrial productivity<\/strong><\/h2>\n\n\n\n<p>Testing is expensive. That&#8217;s why Simcenter testing solutions is also designed to minimize test time. For example: to ensure validity of the setup, a tablet-based Instrumentation app helps to detect and correct potential instrumentation errors. The actual experimental modal test itself consist of suspending the structure in bungees and excite it with a number of simultaneously running shakers. During this excitation, the input forces and resulting accelerations are measured to calculate Frequency Response Functions. If you have ever done such a test, you will agree: it is not easy to ensure that the shakers are properly positioned and the stingers are well-aligned. The Siemens answer to this: self-aligning Simcenter Qsources shakers, which can be mounted directly on the relevant excitation locations.<\/p>\n\n\n\n<figure class=\"wp-block-gallery columns-2 is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\"><ul class=\"blocks-gallery-grid\"><li class=\"blocks-gallery-item\"><figure><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker-1024x576.jpg\" alt=\"\" data-id=\"13457\" data-full-url=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker.jpg\" data-link=\"https:\/\/blogs.sw.siemens.com\/simcenter\/?attachment_id=13457\" class=\"wp-image-13457\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker-1024x576.jpg 1024w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker-600x338.jpg 600w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker-768x432.jpg 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker-1536x864.jpg 1536w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker-1110x624.jpg 1110w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Traditional-shaker.jpg 1920w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"blocks-gallery-item__caption\">Traditional shaker setup with stinger<\/figcaption><\/figure><\/li><li class=\"blocks-gallery-item\"><figure><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"575\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-1024x575.jpg\" alt=\"\" data-id=\"13458\" data-full-url=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-scaled.jpg\" data-link=\"https:\/\/blogs.sw.siemens.com\/simcenter\/?attachment_id=13458\" class=\"wp-image-13458\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-1024x575.jpg 1024w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-600x337.jpg 600w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-768x431.jpg 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-1536x863.jpg 1536w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-2048x1151.jpg 2048w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_2874-1110x624.jpg 1110w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"blocks-gallery-item__caption\">Time-saving, self-aligning Qsources shaker<\/figcaption><\/figure><\/li><\/ul><figcaption class=\"blocks-gallery-caption\">Input to calibrate mode shapes in modal analysis<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Unrivalled Modal parameter estimator: Simcenter Testlab Polymax<\/strong><\/h2>\n\n\n\n<p>Once all data is acquired, modal analysis can start. Within Simcenter Testlab, a model is fit over the measured FRFs, using the well-established Polymax algorithm. The different modes are selected from the Stabilization diagram, either manually or automatically. For highly damped and complex structures, such as trimmed bodies, more advanced algorithms, such as MLMM are crucial.&nbsp; MLMM stands for \u201cmaximum likelihood modal model\u201d and iteratively improves the modal model, while at the same time preparing for better correlation with the CAE model.   <\/p>\n\n\n\n<figure class=\"wp-block-video\"><video controls src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Polymax.mp4\"><\/video><figcaption>Simcenter Testlab Polymax. Simply unrivaled. <\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Final step: make everybody believe that the simulated mode shapes in modal analysis are accurate<\/strong><\/h2>\n\n\n\n<p>The results are now ready to be accessed in Simcenter 3D, where they can be used for comparison of numerical modes, as well as to update the CAE mode. This model will serve to make further optimizations. With this true   digital twin, it now becomes possible to find the right balance between   different performance attributes.<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video controls src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/Correlation.mp4\"><\/video><figcaption>Correlate and update model, ready for accurate performance prediction!<\/figcaption><\/figure>\n\n\n\n<p>Are you interested to learn more about modal analysis process? <br>Here is a webinar explaining this technology step-by-step. <\/p>\n\n\n\n<p><a href=\"https:\/\/www.plm.automation.siemens.com\/global\/en\/webinar\/modal-analysis\/21512\" target=\"_blank\" rel=\"noopener\">WATCH THE WEBINAR<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Learn how to run structural dynamic tests, aka modal test, to derive test-based mode shapes in modal analysis to achieve test-calibrated simulation. <\/p>\n","protected":false},"author":42819,"featured_media":13450,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spanish_translation":"","french_translation":"","german_translation":"","italian_translation":"","polish_translation":"","japanese_translation":"","chinese_translation":"","footnotes":""},"categories":[182],"tags":[305],"industry":[89,132,133],"product":[584,518,588],"coauthors":[],"class_list":["post-13446","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tips-tricks","tag-simrod","industry-automotive-transportation","industry-automotive-oems","industry-automotive-suppliers","product-simcenter-scadas","product-simcenter-testing-solutions","product-simcenter-testlab"],"featured_image_url":"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2020\/04\/DSC_0037-X3.jpg","_links":{"self":[{"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/posts\/13446","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/users\/42819"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/comments?post=13446"}],"version-history":[{"count":5,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/posts\/13446\/revisions"}],"predecessor-version":[{"id":17761,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/posts\/13446\/revisions\/17761"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/media\/13450"}],"wp:attachment":[{"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/media?parent=13446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/categories?post=13446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/tags?post=13446"},{"taxonomy":"industry","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/industry?post=13446"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/product?post=13446"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/simcenter\/wp-json\/wp\/v2\/coauthors?post=13446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}