SD card not accessible since writing image with dd

Question

I've first installed Raspbian via NOOBS (just placed the files on the SD Card using windows), which worked fine and Raspbian was start- and usable. Afterwards I wanted to set an static IP by changing cmdline.txt in boot (like described here: https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=24993 ). Because I've had some issues changing the SD cards content (first I've set the umask wrong when mounting, and after a successfull change I could not mount the boot-partition at all.

To overcome this issues, I've decided to install Raspbian manually by using the image from https://www.raspberrypi.org/downloads/raspbian/ . The sha1-Hash of the download is correct. I've installed the Raspbian via:

sudo dd bs=4M if=2015-11-21-raspbian-jessie.img of=/dev/mmcblk0

Unfortunately is it not possible to boot the Pi from the SD card (the sceen stays black, the red and green light are constantly on) Furthermore, I can not access the file system of the SD card using Ubuntu. The following partitions seem to be available on the SD card:

brw-rw---- 1 root disk 179, 0 Dez  4 13:59 /dev/mmcblk0
brw-rw---- 1 root disk 179, 1 Dez  4 13:58 /dev/mmcblk0p1
brw-rw---- 1 root disk 179, 2 Dez  4 13:58 /dev/mmcblk0p2

gparted says that the file system of both partitions is unknown.

The Raspberry is ok, as it is possible to boot it with a different SD card.

Is there something I've done wrong or something I could try? May the SD card be broken, or is there some problem in the installation process?

EDIT: fdisk -l 2015-11-21-raspbian-jessie.img seems to be right:

Platte 2015-11-21-raspbian-jessie.img: 3934 MByte, 3934257152 Byte
255 Köpfe, 63 Sektoren/Spur, 478 Zylinder, zusammen 7684096 Sektoren
Einheiten = Sektoren von 1 × 512 = 512 Bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Festplattenidentifikation: 0xea0e7380

                         Gerät  boot.     Anfang        Ende     Blöcke   Id  System
2015-11-21-raspbian-jessie.img1            8192      131071       61440    c  W95 FAT32 (LBA)
2015-11-21-raspbian-jessie.img2          131072     7684095     3776512   83  Linux

EDIT 2:

fdisk -l on the SD-card unfortunately does not return the same (and neither on the other partitions):

reichelt@reichelt-ThinkPad-T440s:~/workspaces/irpsimworkspace/backend/backend-utils$ fdisk -l /dev/mmcblk0
Konnte /dev/mmcblk0 nicht öffnen
reichelt@reichelt-ThinkPad-T440s:~/workspaces/irpsimworkspace/backend/backend-utils$ fdisk -l /dev/mmcblk0p1
Konnte /dev/mmcblk0p1 nicht öffnen
reichelt@reichelt-ThinkPad-T440s:~/workspaces/irpsimworkspace/backend/backend-utils$ fdisk -l /dev/mmcblk0p2
Konnte /dev/mmcblk0p2 nicht öffnen

(I assume the output in english would be "Could not open /dev/mmcblk0")

EDIT 3:

But the SD card does not seem to be broken. Detecting badblocks does not find anything:

reichelt@reichelt-ThinkPad-T440s:~/workspaces/irpsimworkspace/backend/backend-utils$ sudo badblocks -o ./badblocks.list -w -s -v -b 4096 -c 16 /dev/mmcblk0
Suche nach defekten Blöcken (Lesen+Schreiben-Modus)
Von Block 0 bis 7593983
Teste mit Muster 0xaa:  84.43% erledigt, 33:26 verstrichen. (0/0/0 Fehler)

EDIT 4:

I have an SD card reader on an Thinkpad T440s with Ubuntu 14.04. The card is realy accessible via /dev/mmcblk0.

After badblocks ran for a longer time, it displayed errors. I've now changed the SD-card and the Pi seems to work fine now. So all in all my lesson learned is to have much more patience for badblocks to finish.